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Increasing the seed germination potential and seedling growth rates play a pivotal role in increasing overall crop productivity. Seed germination and early vegetative (seedling) growth are critical developmental stages in plants. High-power microwave (HPM) technology has facilitated both the emergence of novel applications and improvements to existing in agriculture. The implications of pulsed HPM on agriculture remain unexplored. In this study, we have investigated the effects of pulsed HPM exposure on barley germination and seedling growth, elucidating the plausible underlying mechanisms. Barley seeds underwent direct HPM irradiation, with 60 pulses by 2.04 mJ/pulse, across three distinct irradiation settings: dry, submerged in deionized (DI) water, and submerged in DI water one day before exposure. Seed germination significantly increased in all HPM-treated groups, where the HPM-dry group exhibited a notable increase, with a 2.48-fold rise at day 2 and a 1.9-fold increment at day 3. Similarly, all HPM-treated groups displayed significant enhancements in water uptake, and seedling growth (weight and length), as well as elevated levels of chlorophyll, carotenoids, and total soluble protein content. The obtained results indicate that when comparing three irradiation setting, HPM-dry showed the most promising effects. Condition HPM seed treatment increases the level of reactive species within the barley seedlings, thereby modulating plant biochemistry, physiology, and different cellular signaling cascades via induced enzymatic activities. Notably, the markers associated with plant growth are upregulated and growth inhibitory markers are downregulated post-HPM exposure. Under optimal HPM-dry treatment, auxin (IAA) levels increased threefold, while ABA levels decreased by up to 65 %. These molecular findings illuminate the intricate regulatory mechanisms governing phenotypic changes in barley seedlings subjected to HPM treatment. The results of this study might play a key role to understand molecular mechanisms after pulsed-HPM irradiation of seeds, contributing significantly to address the global need of sustainable crop yield. [Display omitted] • Pulsed high power microwaves (HPM) generated with main frequency 3.5 GHz. • Seed germination significantly increased in all HPM-treated groups. • HPM-treated groups displayed enhancements in water uptake and seedlings growth. • Growth markers upregulated and growth inhibitory markers downregulated by HPM. • Auxin (IAA) levels 3-fold increase, while ABA levels decreased up to 65 % by HPM. [ABSTRACT FROM AUTHOR]

The involvement of the ABA INSENSITIVE 5 (ABI5) binding protein family (AFPs), closely related to NOVEL INTERACTOR OF JAZ (NINJA) proteins, has been revealed in several aspects of plant development related to multifaceted plant abscisic acid (ABA) responses. The abundance of AFP proteins is tightly regulated, and they function as a rheostat for ABA responses through several nonmutually exclusive molecular mechanisms. AFP proteins regulate important biological processes in plants, which are tightly controlled by transcriptional repressors and phytohormone-mediated pathways, specifically ABA, gibberellic acid (GA), and jasmonic acid. In today's world, the most pressing concerns are food security and dynamic climatic conditions. Enriching our knowledge regarding plants' survival and growth strategies through addressing the inherent voids in plant AFP research might foster improvements in various crop species through genetic manipulation. During the course of terrestrial evolution, plants have developed complex networks that involve the coordination of phytohormone signalling pathways in order to adapt to an ever-changing environment. Transcription factors coordinate these responses by engaging in different protein complexes and exerting both positive and negative effects. ABA INSENSITIVE 5 (ABI5) binding proteins (AFPs), which are closely related to NOVEL INTERACTOR OF JAZ (NINJA)-like proteins, are known for their fundamental role in plants' morphological and physiological growth. Recent studies have shown that AFPs regulate several hormone-signalling pathways, including abscisic acid (ABA) and gibberellic acid (GA). Here, we review the genetic control of AFPs and their crosstalk with plant hormone signalling, and discuss the contributions of AFPs to plants' growth and development. [ABSTRACT FROM AUTHOR]

• MgONPs were synthesized through green approach using trichoderma fungus. • Myco-synthesized NPs exhibited strong nematicidal activity. • Soil application of NPs improved plant growth under nematode infection. • Soil application of NPs reduced nematode population and development. Meloidogyne incognita is believed to be the most devastating pest causing severe damage to crops, and hence, innovative and effective means of controlling the nematode is the need of the day. The focus of the current study is to devise an effective and innovative myco-fabrication of MgO nanoparticles (NPs) along with melatonin for efficient management of M. incognita infecting tomatoes. Fungal extracts were used to synthesize the myco-fabricated NPs through a green synthesis pathway and were verified using different spectroscopic means. The nanoparticles exhibited appreciable nematicidal potential, such as drastic egg hatch inhibition and juvenile mortality under in vitro assays. Evaluation of NPs and melatonin in planta, alone or combined form, was investigated on tomato plants already inoculated with M. incognita. The alterations in the nematode population on roots of plants as well as in soil, growth parameters, and biochemical attributes of plants were recorded. A significant reduction in nematode population was revealed on the application of melatonin and myco-fabricated nanoparticles, hence exhibiting an improvement in the plant's biochemical (glutathione, phenolic, flavonoid, and antioxidant enzymes) and growth parameters. A synergistic impact was shown on the combined application of the treatments. Furthermore, an enhancement in the expression as well as activities of antioxidant enzymes was also observed. Increased resistance of plants against nematodes resulted in connection with the improved antioxidant status of plants due to this combined treatment. The significantly improved growth of plants under M. incognita stress conditions reveals the potential of the proposed treatments having synergistic interaction to manage phyto-parasitic nematodes effectively. This presents innovative means of agricultural biotechnologies that have the potential to contribute to the efficient management of nematodes infecting plants. [ABSTRACT FROM AUTHOR]

• Neomarica longifolia is a commercially important ornamental iris plant. • Silicon nanoparticles (SiNPs) along with plant hormones in the medium improved the rate of shoot amplification. • Silicon NPs had a positive impact on the morpho-structural differentiation of leaves. • Silicon NPs also increased chlorophyll contents, rooting efficiency, and acclimatization of plantlets. Neomarica longifolia (Link & Otto) Sprague is a commercially important ornamental iris plant. This study aimed to explore in vitro regeneration and the relevance of silicon nanoparticles during the shoot amplification phase and their impact on the subsequent development of plants, structural differentiation, and rooting efficiency of N. longifolia. A maximum number of shoots (4.3 per explant) from node explants was recorded on Murashige and Skoog's (MS) medium augmented with 1.5 mg L−1 6-benzylaminopurine (BAP). However, lower concentration of BAP (0.5 mg L−1) combined with 0.2 mg L−1 Indole-3-acetic acid (IAA) were optimal for multiple shoot production (9.3 shoots). The foliages of such shoots were structurally weak and underdeveloped with reduced photopigments. The incorporation of 2.0 mg L−1 SiNPs in the nutrient solution showed a positive impact on the rate of amplification (15.0 shoots per explant) and well differentiation of mechanical and vascular tissues and photopigments. The increased concentrations of SiNPs (beyond optimum) decreased the above-studied parameters. The shootlets obtained from optimized concentrations of SiNPs along with optimum plant growth regulators (PGRs) rooted maximum (94.5 % response, 13.0 roots per shoot) on ½ MS medium + 0.5 mg L−1 Indole-3-butyric acid (IBA) and survived well in the greenhouse. We, therefore, hypothesize that the incorporation of optimal SiNPs (2.0 mg L−1) along with optimal PGRs at the shoot proliferation phase is important for upregulating the rate of shoot amplification, differentiation of foliar architecture, synthesis of photopigments, root development, and survival of the plantlets during hardening. Furthermore, the present study addressed the limitations of in vitro -induced morpho-structural disorders by introducing SiNPs in the medium. [ABSTRACT FROM AUTHOR]

Strigolactones (SLs) are structurally diverse and divided into canonical and non-canonical subgroups. SLs are generally considered as plant hormones, best known for inhibiting shoot branching/tillering. SLs are rhizospheric signals important for arbuscular mycorrhizal symbiosis, which may be their ancestral function that is conserved from liverworts to flowering plants. Recent results have revealed functional specificity, indicating that canonical SLs are not the tillering/branching inhibitory hormone in rice or tomato. Increasing the content of 4-deoxyorobanchol in rice by interrupting its hydroxylation affects root, shoot, and panicle growth, suggesting that this canonical SL has hormonal functions. Reducing the levels of canonical SLs by genome editing or applying specific inhibitors is a promising strategy for reducing Striga parasitism. Strigolactones (SLs) act as regulators of plant architecture as well as signals in rhizospheric communications. Reduced availability of minerals, particularly phosphorus, leads to an increase in the formation and release of SLs that enable adaptation of root and shoot architecture to nutrient limitation and, simultaneously, attract arbuscular mycorrhizal fungi (AMF) for establishing beneficial symbiosis. Based on their chemical structure, SLs are designated as either canonical or non-canonical; however, the question of whether the two classes are also distinguished in their biological functions remained largely elusive until recently. In this review we summarize the latest advances in SL biosynthesis and highlight new findings pointing to rhizospheric signaling as the major function of canonical SLs. [ABSTRACT FROM AUTHOR]

• Salicylic acid (SA) has encouraging effects on the growth and development of plants. • SA stimulates signalling in plants via several stress proteins and genes. • SA positively interacts with other phytohormones. • SA enhances plant tolerance towards abiotic stress. Drastic change in global climatic conditions has significantly increased the frequency of abiotic stresses, such as different temperature regimes (high, low, or freezing stress), uneven precipitation leading to flooding or drought, soil salinization, cyclones and hurricanes which pose a major challenge to the crop productivity and food security. Therefore, it becomes imperative for the global science community to engineer stress tolerance in crop plants to ensure enough food for the globe. Plant growth regulators play an important function in stress management. One putative plant hormone that aids plants in coping with biotic and abiotic stressors is salicylic acid (SA). SA also cooperates with other phytohormones, such as gibberellins, auxins, abscisic acid, jasmonic acid, ethylene, polyamines, nitric oxide, and to counter the negative effects of environmental perturbations. Moreover, SA shields plants from oxidative stress by reducing the production of reactive oxygen species in challenging circumstances. Additionally, SA stimulates gas exchange, photosynthesis, and osmolyte synthesis in plants, which counteract the damage caused by ROS. Exogenous application of SA to agricultural crops including medicinal and aromatic plants improves their abiotic stress tolerance, either individually or in combination with other phytohormones. SA can stimulate the production of secondary metabolites by controlling the expression of stress-related genes, activating or regulating several key enzymes, and balancing the ion content. The present review summarizes the various mechanisms by which SA confers abiotic stress tolerance in plants through homeostasis, signalling, and crosstalk with other phytohormones. [ABSTRACT FROM AUTHOR]

Arsenic (As) toxicity in crops is a major global concern, adversely affecting sustainable agricultural practices, and serving as a potential carcinogenic pollutant. As contamination in soil poses a significant threat to plant health and productivity, adversely impacting growth, photosynthesis, and the antioxidant system. To address this issue, plants endogenously regulate the levels of various phytohormones, and the exogenous application of phytohormones to mitigate As-induced stress has gained significant attention. Phytohormones act as secondary (2°) messengers, participating in diverse signaling cascades under As stress. As uptake in plants leads to the As-accumulation and generation of excessive reactive oxygen species (ROS) which can be alleviated by phytohormones. Numerous studies have highlighted the role of phytohormones, such as auxins, methyl jasmonates, salicylic acid, brassinosteroids, and Mel, in regulating pathways that enhance plant growth, biomass accumulation, ROS scavenging, antioxidative enzyme and photosynthesis under As stress. This review summarizes the detailed mechanism of As phytotoxicity, its detoxification mechanism, and the exogenous application of phytohormones to alleviate As stress. Additionally, we provide insights into recent findings on the possible roles of various genes, proteins, transgenic factors, and genome editing approaches in phytohormone-mediated As-stress tolerance. [Display omitted] [ABSTRACT FROM AUTHOR]

Root architecture has a key role in influencing plant growth and yield. In recent years, the agriculture sector has gained interest in harnessing the potential of plant growth-promoting rhizobacteria (PGPR) that possess the competence to produce phytohormones, with the aim of enhancing these desirable traits. Phytohormone-producing PGPR exert their influence on root development through the modulation of phytohormone production and distribution, encompassing auxins, cytokinins, and gibberellins. These beneficial bacteria stimulate lateral root proliferation, elongate root hairs, and promote the accumulation of root biomass, ultimately leading to heightened nutrient uptake and enhanced water absorption. Moreover, the phytohormones synthesized by PGPR serve to activate stress signalling pathways, thereby strengthening plant resilience against an abiotic stressor, viz., drought, heavy metal, salinity, and toxicity. This comprehensive review article highlights the role of these PGPR and their significant impact on augmenting root architecture in plants. The development of roots is often vulnerable to several abiotic factors, which in turn adversely affects the initial growth and overall health of the plants. This review thoroughly explores the complex interaction of phytohormones in mitigating abiotic stresses through their modulation of root development. Additionally, the interaction between phytohormone-producing PGPR and nanoparticles (NPs) has emerged as a significantly promising approach to reinforce plant growth and an ability to improve the colonization and activity of PGPR in the rhizosphere, further expanding their beneficial effects on root architecture and stress tolerance. Within this context, we have discussed the stimulating dynamics of PGPR interaction with NPs in sustaining root architecture to optimize plant health and effectively mitigate abiotic stresses. [Display omitted] • Root architecture shapes plant growth, and harnessing phytohormone-producing PGPR holds promise for enhancing desirable traits. • Phytohormone-producing PGPR modulates root development, promoting lateral root proliferation and enhanced nutrient uptake. • This review explores how phytohormones mitigate abiotic stress by influencing root development in plants. • Interaction of phytohormone-producing PGPR with nanoparticles amplifies their effects on root architecture and stress tolerance. [ABSTRACT FROM AUTHOR]

• Topping induces redistribution of potassium ions among different tissues of tobacco. • Topping-induced potassium redistribution is closely related to plant hormones. • IAA and CBL-CIPK pathway play key roles in the regulation of potassium metabolism. Topping is typically used in tobacco production to reduce reproductive consumption. However, following topping, declines in potassium content in tobacco leaves often have adverse effects on leaf growth, development, and quality. In this study, the mechanism of the topping-induced redistribution of potassium in the tobacco was studied based on physiological and ecological theories and molecular biology techniques. Our findings showed that the changes in potassium content in different parts of the tobacco after topping were closely correlated to the content of endogenous hormones, and the gray relational coefficient between potassium content and indole-3-acetic acid (IAA) content was the highest. Transcriptome sequencing and qRT-PCR analysis verified that the redistribution of potassium in tobacco plants induced by topping was mediated by the IAA signaling pathway and the CBL-CIPK signaling pathway. In addition, the genes of the NtPIN, NtPOT, NtSKOR , and NtCIPK families were found to play a significant role in the regulation of endogenous hormones and potassium metabolism in tobacco plants. Our study provides an important theoretical basis and data for elucidating the mechanism by which potassium metabolism is regulated in plants. The study also proposes a new approach for balancing the yield and quality of tobacco leaves using appropriate topping methods. [ABSTRACT FROM AUTHOR]

Maize is an important food crop that is affected by salt stress during growth, which can hinder plant growth and result in a significant decrease in yield. The application of plant growth-promoting rhizobacteria can improve this situation to a certain extent. However, the gene network of rhizosphere-promoting bacteria regulating the response of maize to salt stress remains elusive. Here, we used metabolomics and transcriptomics techniques to elucidate potential gene networks and salt-response pathways in maize. Phenotypic analysis showed that the Bacillus atrophaeus treatment improved the plant height, leaf area, biomass, ion, nutrient and stomatal indicators of maize. Metabolomic analysis identified that differentially expressed metabolites (DEMs) were primarily concentrated in the arginine, proline and phytohormone signaling metabolic pathways. 4-Hydroxyphenylacetylglutamic acid, L-histidinol, oxoglutaric acid, L-glutamic acid, L-arginine, and L-tyrosine were significantly increased in the Bacillus atrophaeus treatment. Weighted gene coexpression network analysis (WGCNA) identified several hub genes associated with salt response: Zm00001eb155540 and Zm00001eb088790 (ABC transporter family), Zm00001eb419060 (extra-large GTP-binding protein family), Zm00001eb317200 (calcium-transporting ATPase), Zm00001eb384800 (aquaporin NIP1–4) and Zm00001eb339170 (cytochrome P450). Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that genes related to plant hormone signal transduction and the MAPK signaling pathway were involved in the response to the effect of Bacillus atrophaeus under salt stress. In the plant hormone signal transduction pathway, 3 differentially expressed genes (DEGs) encoding EIN3/EILs protein, 3 DEGs encoding GH3, 1 DEG encoding PYR/PYL and 6 DEGs encoding PP2C were all upregulated in Bacillus atrophaeus treatment. In the MAPK signaling pathway, 2 DEGs encoding CAT1 and 2 DEGs encoding WRKY22/WRKY29 were significantly upregulated, and the expression of DEGs encoding RbohD was downregulated by the application of Bacillus atrophaeus. In conclusion, the application of Bacillus atrophaeus under salt stress regulated key physiological and molecular processes in plants, which could stimulate the expression of genes related to ion transport and nutrients in maize, alleviate salt stress and promote maize growth to some extent, deepening our understanding of the application of Bacillus atrophaeus under salt stress to improve the salt-response gene network of maize growth. [Display omitted] • Bacillus atrophaeus significantly enhanced maize seedling growth and physiological indexes under salt stress. • WGCNA identified several hug genes associated with the salt response. • Plant hormone transduction and MAPK signaling pathways were involved in the response of Bacillus atrophaeus to salt stress. [ABSTRACT FROM AUTHOR]

• Salt stress damages chlorophyll, gas exchange, and the growth of nasturtium. • Phytohormones decrease the harmful effects of salt stress in nasturtium. • Phytohormones may be a strategy to alleviate the damage caused by salt stress. Salt stress constitutes a significant challenge in contemporary agriculture, particularly in arid and semi-arid regions. The utilization of cytokinins, jasmonic acid, and salicylic acid has been employed as a strategy to mitigate the damage induced by this stress in horticultural crops. Nasturtium (Tropaeolum majus L.) is an edible flower native to South America and cultivated throughout the world. The objective of this work was to evaluate the effects of the application of salicylic acid, jasmonic acid, and cytokinin on chlorophyll fluorescence, gas exchange, and dry mass of nasturtium grown under salt stress. Salt stress promoted damage to the photosynthetic apparatus, which caused a decrease in gas exchange and, consequently, in the phytomass of nasturtium plants. The application of phytohormones mitigated damage to the photosynthetic apparatus and gas exchange. As a result, plant growth (phytomass) was less affected by stress when cytokinin and salicylic acid were administered. Therefore, these phytohormones may serve as a viable strategy to ameliorate the damage caused by salt stress in nasturtium. [ABSTRACT FROM AUTHOR]

Sitobion avenae F. is a highly prevalent and devastating pest in wheat crops, leading to significant yield losses. Silicon (Si) has been widely recognized as an effective inducer of plant resistance against aphids. Nevertheless, the underlying mechanisms governing the physiological and biochemical responses of plants induced by Si defense against S. avenae F. remain incompletely understood. In this study, we conducted experiments by treating wheat leaves with varying concentrations of Tetraethyl orthosilicate (TEOS) spray under aphid infestation. We meticulously observed and recorded the life cycle of S. avenae F. and measured the content of plant hormones, secondary metabolites, and the activity of defense enzymes in wheat leaves. Furthermore, we utilized structural equation modeling to discern the causal correlation between aphid performance and the physiological-biochemical responses of wheat under TEOS sprays. Our findings revealed that a concentration of 3 mmol/L TEOS significantly shortened the net reproductive rate, intrinsic rate and finite rate of increase, and mean generation time of S. avenae F., while simultaneously prolonging the population doubling time. Additionally, the content of lignin, total phenolics, flavonoids, alkaloids, tannin, jasmonic acid (JA), and salicylic acid in wheat leaves exhibited a substantial increase. Furthermore, the activity of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), catalase, and lipoxygenase in wheat leaves was significantly enhanced. Our results suggest that TEOS spray reduced the survival and population growth of S. avenae F. while enhancing the defense response of wheat against aphids by activating the activity of PAL and PPO in wheat, and increasing the content of total phenolic and JA. This work provides valuable insights for the development of appropriate Si fertilizers for effective pest management and offers robust theoretical support for wheat aphid control through agricultural fertilization strategies. [ABSTRACT FROM AUTHOR]

• Calcium (Ca) exhibits encouraging effects on the growth and development of plants. • Ca stimulates signalling in plants via several stress proteins and genes. • Ca regulates a wide range of fundamental processes. • Ca enhances plant tolerance towards abiotic stress. The impact of environmental stresses like drought, salinity, extreme temperatures, and high salinity on plants is evident in various physiological, biochemical, and molecular processes. These stressors lead to reduced growth and yield potential. They produce the accumulation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in cells, causing stomatal closure and a decrease in photosynthetic activity. This ultimately results in a loss of crop productivity. Calcium (Ca) serves as a secondary messenger in plants, detected by cellular proteins such as CaM-CAMTAs, CBL1-CIPK, and CDPKs. It plays a crucial role in regulating stress-related genes like RD29A/B and KIN1/2. Calcium is considered a key player in enhancing stress tolerance in plants. Whether applied independently or in conjunction with exogenous plant hormones like salicylic acid, ethylene, abscisic acid, jasmonic acid, and polyamines, it significantly contributes to mitigating abiotic stress. There are various methods to deliver Ca to plants, including seed priming, seed hardening, soil application, and foliar feeding. This review emphasizes the role of Ca, its transportation, sensing mechanisms by cellular proteins (such as CaMs, CBLs, and CDPKs), and the underlying molecular processes in plants under abiotic stress conditions. [ABSTRACT FROM AUTHOR]

The production of horticulture crops is severely restricted by abiotic stress factors such as salinity, drought, temperature fluctuation (low and high), and heavy metals (HMs). Abiotic stress causes metabolic changes in horticultural plants that impair growth and productivity. In this era of global climate change, extreme environmental conditions reinforce the situation and severely limit plant growth and productivity. Researchers have been investigating for a long time to determine how resilience and response to environmental stress elements. The use of phytohormones to mitigate the adverse effects of abiotic stresses on horticultural plants has been widely acknowledged as a powerful strategy. Salicylic acid (SA) has been extensively studied for its importance in improving plant abiotic stress tolerance. However, the processes that may underlie SA-induced plant tolerance to significant abiotic stressors are still poorly understood. Based on recent reports, this paper provides an overview of the role of SA in horticultural plants under both optimal and stressful conditions; critically evaluates the role of SA in plants exposed to key abiotic stresses; discusses potential mechanisms potentially governing SA-induced plant abiotic stress-tolerance; and briefly highlights significant aspects that have yet to be explored in the current context. [Display omitted] • Abiotic stresses significantly hindered plant growth and development. • Salicylic acid is a phenolic molecule that regulates plant growth and development. • Salicylic acid efficiently protected leaf photosynthetic efficiency under stress environment. • Salicylic acid reduced oxidative damage and increased antioxidant enzymes activity. [ABSTRACT FROM AUTHOR]

Abiotic stressors threaten the survival mechanism of plant life on Earth. Phytohormones are one of the defensive molecules produced by plants to counteract destructive effects elicited by abiotic stresses. In recent years, melatonin has gained prime importance in plant research because of its regulatory role in abiotic stress tolerance. Melatonin plays a central role in interacting with other phytohormones such as auxin, gibberellin, cytokinin, abscisic acid, ethylene, brassinosteroids, jasmonic acid, salicylic acid and plant growth regulators like nitric oxide, polyamines, γ-aminobutyric acid and serotonin to regulate stress alleviation for maintaining basal growth under harsh environmental conditions. The precise understanding of intricate web of crosstalk mechanisms among different phytohormones and their interconnected networks in terms of synergistic and antagonistic actions is crucial for maintaining cellular dynamics under unfavorable conditions. Therefore, in the present review, we mainly focused on crosstalk regulatory circuits operated by melatonin with other phytohormones at both physiological and molecular levels and their responses under known abiotic stress environment. The biosynthesis, signaling pathway and efficacy of melatonin in various stress avoidance are also enumerated in this review. Indeed, it would not be presumptuous to hope that this review will be helpful for designing climate-smart crop cultivars in the forthcoming years using melatonin as the major stress mitigator and endogenous signaling molecule during stressful situations. [Display omitted] • Biosynthesis of melatonin in plants is more complex than in animals. • Melatonin receptor CAND2/PMTR1 participates in melatonin-mediated signal perception, involving mitogen activated protein kinase-signaling cascades to enhance stress tolerance. • Melatonin interacts with different phytohormones for conferring stress protection. • Melatonin and phytohormones crosstalk operates synergistically or antagonistically, depending on the nature and complexity of stress, plant type and surrounding environment. [ABSTRACT FROM AUTHOR]

Plant hormones are small molecules that regulate plant growth, development, and responses to biotic and abiotic stresses. They are specifically recognized by the binding site of their receptors. In this work, we resolved the binding pathways for eight classes of phytohormones (auxin, jasmonate, gibberellin, strigolactone, brassinosteroid, cytokinin, salicylic acid, and abscisic acid) to their canonical receptors using extensive molecular dynamics simulations. Furthermore, we investigated the role of water displacement and reorganization at the binding site of the plant receptors through inhomogeneous solvation theory. Our findings predict that displacement of water molecules by phytohormones contributes to free energy of binding via entropy gain and is associated with significant free energy barriers for most systems analyzed. Also, our results indicate that displacement of unfavorable water molecules in the binding site can be exploited in rational agrochemical design. Overall, this study uncovers the mechanism of ligand binding and the role of water molecules in plant hormone perception, which creates new avenues for agrochemical design to target plant growth and development. [ABSTRACT FROM AUTHOR]

• The integrated analysis of metabolome and transcriptome in Z. planispinum var. Dintanensisin grown at different altitude are first reported within this study. • The altitude significantly affects the gene expression, and composition of secondary metabolites in leaves, and flavonoid metabolism may dominate the resistance of Zanthoxylum planispinum var. Dintanensis to the adverse environmental stress in rocky desertification control areas. • More flavonoids and phenolic acids were accumulated in higher altitudinal level, while more terpenoids, aldehyde and ester were distinctly increased in lower altitudinal level. Therefore, it is much more complicated to gain maximum medicinal productions of Z. planispinum var. Dintanensis. To analyze the effects of altitude on Z. planispinum var. Dintanensisin, leaves of samples from different altitudes (H1:1054 m.a.s.l., H2:821 m.a.s.l., H3:645 m.a.s.l.) were collected for integrative analysis of the metabolome and transcriptome in the present study. According to transcriptome data, a total of 9,566 differentially expressed genes (DEGs) were identified from the three sample comparisons (H1 vs. H2, H1 vs. H3, H2 vs. H3). Fewer DEGs were observed in the H2 vs. H3 group than in the other two comparison groups, suggesting that differences in the transcriptome increased with elevation. Most genes were involved in "Biosynthesis of secondary metabolites", "Plant hormone signal transduction" and "MAPK signaling pathway-plant" based on KEGG enrichment analysis. In total, 423 differential metabolites (DAMs) were determined in the three comparisons (mentioned above) by using metabolomics analysis, of which flavonoids (14.91%) were dominant. Interestingly, more accumulation of terpenoids, aldehydes and esters was observed at higher altitudinal levels, while higher percentages of flavonoids and polyphenols were obtained at lower altitudes based upon K-Means analysis. A unique pathway (p value<0.01) linked to "flavonoid biosynthesis" appeared to have consistent expression patterns in the comparison of H1 vs. H3 based on network analyses of DEGs and DAMs. Notably, regarding the direct products of catalytic reactions, naringenin chalcone, aromadendrin, and naringenin were positively regulated by genes encoding CHS, F3H and CHI, respectively. In addition, the transcription levels of nine candidate genes, including CHI, CHS, CCoAOMT, 2ODDs, ANS, ANR, F3H, DFR and HCT , were confirmed by RT‒qPCR, which were consistent with transcriptional profile data regarding RNA-seq and further demonstrated that these genes involved in flavonoid biosynthesis contribute to the environmental adaptation of the blade in Z. planispinum var. Dintanensis. In summary, our findings represent the first integration of transcriptome data with widely targeted metabolomic data from Z. planispinum var. Dintanensis grown in rocky desertification control areas, which provides novel insights into adaptation to environmental stress. This study has the potential to improve the cultivation and management of Z. planispinum var. Dintanensis through various technologies to gain maximum medicinal production in the future. [ABSTRACT FROM AUTHOR]

Auxins are a group of pivotal hormones that regulate almost all aspects of plant growth, and synthetic auxin herbicides are broadly used in agriculture worldwide. In particular, polar auxin transmembrane transport directs patterns of development such as gravitropic and phototropic growth, as well as apical dominance, embryogenesis, organogenesis, and organ development. The PIN-FORMED (PIN) family mediates auxin export from the cytosol and controls polar auxin transport direction and strength. Recent structural studies of PIN1, PIN3, and PIN8 explain the molecular mechanism of auxin export by PINs. The results are a big step towards understanding plant development in response to environmental cues, as well as for our ability to predict and augment plant growth. Auxins are pivotal plant hormones that regulate plant growth and transmembrane polar auxin transport (PAT) direct patterns of development. The PIN-FORMED (PIN) family of membrane transporters mediate auxin export from the plant cell and play crucial roles in PAT. Here we describe the recently solved structures of PIN transporters, PIN1, PIN3, and PIN8, and also their mechanisms of substrate recognition and transport of auxin. We compare structures of PINs in both inward- and outward-facing conformations, as well as PINs with different binding configurations for auxin. By this comparative analysis, a model emerges for an elevator transport mechanism. Central structural elements necessary for function are identified, and we show that these are shared with other distantly related protein families. [ABSTRACT FROM AUTHOR]

• In the era of frequently changing global climatic conditions, abiotic stresses pose serious threat to crop production and food security. • Soil salinization becomes a major limiting factor for restricting the plant growth and development, thus crop yield. • Plant-microbe interaction especially the root endophyte, serendipita (Piriformospora) indica with broad host range have the potential for stress resilience and growth promotion in sustainable manner. Abiotic stresses come in a new form with changing global climatic conditions and make their way by disrupting the vital physiological, biochemical and molecular events of plants leading to significant yield losses. Among various abiotic stresses, salinity stress is one of the major abiotic constraints to plant growth and production globally. Salinity causes several destructive effects such as oxidative stress, osmotic stress, and imbalance in the nutrients uptake in plant system that creates difficult situation for the normal metabolic functioning. Plants are capable enough to make adjustments and adapt diverse defense approaches including stress signaling, maintenance of antioxidant machinery, ability to decrease the toxic molecule level and regulation of the plant hormone levels to sustain under stressful conditions. These strategies can be more effectively improved with the help of certain microbes in better dealing with an undesirable environment. Microbe association with the plant makes a great alliance that builds tolerance mechanism more robust and promotes the activities of various enzymes, hormonal regulation, and transport of important elements. Microbes act as a mediator agent between the stress and host plants. In the recent years, the endophytic fungus, Piriformospora (Serendipita) indica comes as a friend indeed with the ability to colonizing the roots of the wide host range of plant, fighting the stresses and enlarges the survival and performance of plants. In this review, we focused on an appropriate understanding of plant-microbe association impact in dealing with stress situations. [ABSTRACT FROM AUTHOR]

• Drought disrupts plant hormone balance, affecting growth and development. • Melatonin modulates hormone levels and regulates plant responses to drought stress. • Melatonin regulates physiological functions and boosts plant vigor during stress. • Numerous stress response pathway genes' expression is regulated by melatonin. • Omics employs understanding melatonin biosynthesis and signaling pathways. With recent global climate change, the consequences of common extreme meteorological events have attracted increasing attention worldwide. Drought is an extreme meteorological event whose duration, frequency, and spatial extent, among other abiotic stresses, exhibited an increasing trend and significantly affect agriculture production. Researchers are trying to enable different drought management strategies by developing transgenic methods and using exogenous organic and inorganic substances in agriculture. Melatonin, an indolamine molecule also present in plants, has proven its effectiveness against various abiotic stresses, including drought in several crops. The main purpose of this review is to describe the biological function of melatonin, including signaling pathways and mechanisms in plants under different stress conditions. The focus was the results suggesting the use of melatonin as a promising strategy to mitigate the negative effects of drought stress on plant biological and physiological functions. Moreover, the molecular and genetic mechanisms underlying the application of melatonin for different plant species and growth conditions are also included to provide insight into the biosynthesis and signaling pathways, functional characterization of genes, and gene expression regulation. Future perspectives are given to broaden the scope of studies on melatonin application optimization in order to understand the mechanisms involved and develop strategies to improve crop resilience to stress and the optimal dosage for agricultural settings. [ABSTRACT FROM AUTHOR]

The aim of this in vitro study was to examine the potential effect of functional food plant extracts, namely, extracts of flaxseed (Linum usitatissimum L.), chia (Salvia hispanica) and puncture vine (Tribulus terrestris L.), on basic mare ovarian cell functions and their response to the environmental contaminant toluene. Mare granulosa cells were incubated with and without toluene (0, 0.02, 0.2 or 2.0 μg/mL) in the presence or absence of flaxseed, chia and puncture vine extracts (10 μg/mL). Markers of cell proliferation (accumulation of proliferating cell nuclear antigen, PCNA) and apoptosis (accumulation of bax), viability (Trypan blue extrusion) and the release of progesterone (P), oxytocin (OT) and prostaglandin F 2 alpha (PGF) were measured. Toluene reduced all other measured parameters except OT release. All the tested plants were able to reduce cell viability and the release of P and PGF, but they did not influence other indexes. Moreover, flaxseed mitigated toluene action on ovarian cell proliferation, apoptosis, OT and PGF, whilst puncture vine prevented and inverted toluene action on P and PGF ourput. Chia extract did not modify toluene action on any parameter. On the other hand, toluene was able to promote the inhibitory action of flaxseed on cell viability and P release and to prevent the inhibitory action of all the plant extracts on PGF release. The present study (1) is the first demonstration, that flaxseed, chia and puncture vine can directly suppress mare ovarian cell functions, (2) shows that toluene can suppress basic ovarian cell functions and modify the reproductive effect of food plants and (3) demonstrates the ability of flaxseed and puncture vine, but not of chia, to prevent some toxic effect of toluene on mare ovarian cell functions. • Toluene can reduce viability, proliferation, apoptosis and hormones release by these cells and modify ovarian cell response to plants. • Flaxseed, chia and puncture vine can directly down-regulate viability, and progesterone and prostaglandin F release by mare ovarian cells. • Flaxseed and puncture vine, but not of chia can prevent the toxic effect of toluene on mare ovarian cell functions. [ABSTRACT FROM AUTHOR]

• Plant synthesized hormones are essential to counteract stress conditions. • Strigolactones (SLs), a novel phytohormones, regulate plant development and interactions. • SLs crosstalk with other phytohormones is vital for plant health. • SLs fights both biotic and abiotic stress by increasing tolerance level in plants. Plants respond to a range of abiotic stimuli in nature involving anatomical, cellular, morphological, and physiological changes. The adaptability of plants to acclimatize to different environments is greatly influenced by phytohormones, which mediate growth, development and nutrient partitioning. These signal molecules are biosynthesized by plant itself and are often known as plant growth regulators. Strigolactones (SLs) are a unique class of phytohormones that have an ecological role in overcoming multiple stress circumstances. SLs are originally found in the germinating seeds of parasitic weeds, biosynthesized from precursor carotenoids and perform widespread physiological functions in bud outgrowth, shoot branching, nodulation, and photomorphogenesis. SLs correspondingly persuade arbuscular mycorrhizal fungi's hyphal branching in germinating spores. Lately, SLs have been drawn to attention as of their role in molecular and physiological adaptations in response to abiotic stresses. The SLs demonstrate crosstalk with other phytohormones and function in mitigating stress conditions through diverse molecular pathways. The present review addresses comprehensive information about the molecular signaling, biosynthesis, and importance of SLs in providing resilience towards stress conditions in diverse plants. [ABSTRACT FROM AUTHOR]

• HP gene family contained 224 HP genes from 17 species. • The phylogenetic analysis classified HP genes into six clades. • Sequence logos exhibited a highly conserved pattern of amino acids. • GhHP genes exhibited high expression in roots. Histidine phosphotransfer (HP) genes are involved in cytokinin signaling and stress responses in Arabidopsis and rice. However, HP genes have not been reported in Gossypium species. Here, we comprehensively identified 224 HP genes in 17 plant species. The phylogenetic analysis classified HP genes into six clades. Gene structure and protein motif analysis of GhHP genes demonstrated well-conserved intron/exon and motif configuration within the same group. Chromosomal location outcomes indicated the mapping of 25 GhHP genes on 14 chromosomes, with the maximum number of genes on chromosome D06. Numerous cis- regulatory elements related to phytohormones, abiotic stress, growth, light responsiveness, meristem expression, and flavonoid biosynthesis were predicted in the promoter regions of GhHP genes. Sequence logos exhibited a highly conserved pattern of amino acids in the Gossypium species. Gene duplication depicts that gene loss or addition occurs mainly through segmental or whole-genome duplication. Further, collinearity analysis identified 90 and 33 orthologous gene pairs in G. hirsutum and G. barbadense , respectively. Ghi-miRN530, Ghi-miRN1478, and Ghi-miRN1478 targeted GhHP9, GhHP19, and GhHP23 , respectively. The GhHP genes (GhHP7, GhHP9 , and GhHP21) exhibited preferential expression in roots. Further, GhHP genes (GhHP13 and GhHP23) were significantly upregulated under abiotic stress (cold, heat, PEG, and salt) with few exceptions, indicating their significant role in the root and abiotic stress responses. Our research provides a substantial understanding of GhHP genes and offers a foundation for further investigation of HP genes for cotton breeding. [ABSTRACT FROM AUTHOR]

Salicylic acid (SA) is an aromatic plant hormone mediating plant growth, development, and immunity, including local and systemic defenses against pathogens and pests. Research for the past three decades has advanced our understanding of the SA pathway, from metabolic enzymes and receptors to signaling components and gene regulation. Key components of SA biosynthesis, signaling, metabolism, and transport are impacted by changing abiotic (e.g., temperature, water availability) and biotic factors (e.g., commensal and beneficial microbes). Temperature regulation of the SA pathway has led to the discovery of major thermosensitive nodes at various levels of gene/protein regulation. Microbiome modulation of the SA pathway at the single species and community levels are being disentangled, revealing mechanisms that rely on canonical plant hormone crosstalk. Salicylic acid (SA) is a central plant hormone mediating immunity, growth, and development. Recently, studies have highlighted the sensitivity of the SA pathway to changing climatic factors and the plant microbiome. Here we summarize organizing principles and themes in the regulation of SA biosynthesis, signaling, and metabolism by changing abiotic/biotic environments, focusing on molecular nodes governing SA pathway vulnerability or resilience. We especially highlight advances in the thermosensitive mechanisms underpinning SA-mediated immunity, including differential regulation of key transcription factors (e.g., CAMTAs, CBP60g, SARD1, bHLH059), selective protein–protein interactions of the SA receptor NPR1, and dynamic phase separation of the recently identified GBPL3 biomolecular condensates. Together, these nodes form a biochemical paradigm for how the external environment impinges on the SA pathway. [ABSTRACT FROM AUTHOR]

Brassinosteroids (BRs) are exceptional phytohormones: they do not undergo a long-distance transport between plant organs. However, the mechanism of short-distance (intercellular) transport of BRs remains poorly understood. Recently, Wang et al. provided a novel insight into the mutual dependence of BR homeostasis, their intercellular transport, and plasmodesmata permeability. [ABSTRACT FROM AUTHOR]

As a major environmental factor impacting the seasonal growth and geographical distribution of plants, temperature change significantly affects crop quality and productivity. Ethylene is a gaseous hormone with an important role in plant growth, development, and multiple stress responses, including heat and cold. Temperature stress affects ethylene biosynthesis and signaling pathways, with APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) transcription factors being the main node of ethylene-mediated temperature stress response. Crosstalk among different phytohormones also alters and regulates the expression of temperature stress-responsive genes. Temperature influences the seasonal growth and geographical distribution of plants. Heat or cold stress occur when temperatures exceed or fall below the physiological optimum ranges, resulting in detrimental and irreversible damage to plant growth, development, and yield. Ethylene is a gaseous phytohormone with an important role in plant development and multiple stress responses. Recent studies have shown that, in many plant species, both heat and cold stress affect ethylene biosynthesis and signaling pathways. In this review, we summarize recent advances in understanding the role of ethylene in plant temperature stress responses and its crosstalk with other phytohormones. We also discuss potential strategies and knowledge gaps that need to be adopted and filled to develop temperature stress-tolerant crops by optimizing ethylene response. [ABSTRACT FROM AUTHOR]

• Demonstrated the better suitability of F1 hybrid for gynogenesis and induction of haploids for the first time. • Flow cytometer confirms high frequency of induced haploids through gynogenesis. • This study establishes the suitability of polymorphic SSRs in detection of haploids from an F1 hybrid. • Significant heterosis for all important parameter of gynogenesis was recorded across the treatments which is first of kind information in vitro gynogenesis of any plant species. • Higher sucrose concentration and combined pre-treatment with cold and heat shock treatments were very useful for induction of large number of ELS. The present study was undertaken to develop an efficient protocol in cucumber for induction of large number haploids through gynogenesis and to understand the effects of heterosis on gynogenesis. One natural variant, DC-48 with exceptionally high shelf life along with another genotype, DC-83 with very low shelf-life and the F 1 hybrid using these contrasting parents were used donor mother plants for in vitro gynogenesis. Effects of developmental stages, plant hormones, sucrose concentration and combined cold and heat shock pre-treatment were studied. For the first time, we are reporting significant heterosis for important parameters of gynogenesis using a F 1 hybrid and their corresponding parental lines as donor genotypes. Unpollinated ovules cultured at one day prior to anthesis was most suitable developmental stage for efficient induction of embryo like structures (ELS) and haploids. Basal MS based media supplemented with 5.0 mg/L Zeatin and 0.2 mg/L NAA was most effective in induction of large number of ELS in all three genotypes. A combination of low temperature pre-treatment and high temperature heat shock treatment after culture was very useful in formation of ELS. Cold pre-treatment at 9 °C for 4–6 days followed by heat shock treatment at 32 °C for 2–4 days were ideal temperature shock treatment for high frequency direct regeneration. A large set of polymorphic and uniformly distributed SSRs were used to confirm hybridity and allelic distribution of the developed plants through gynogenesis using F 1 hybris as mother plant. The ploidy level determined through flow cytometer validated the SSR based detection of ploidy level. This novel approach was suitable in identifying the plants developed from female gametocytes. It was interesting that all the regeneration related traits exhibited significant heterosis in desirable direction across the treatments suggesting the role of heterosis in gynogenesis of cucumber. The findings of the study will facilitate development of large number haploids and doubled haploids for genetic studies and understanding the shelf-life in cucumber. Besides, this study will be instrumental to investigate the metabolic processes and organogenetic changes associated with high frequency regeneration and induction of haploids in response to combined cold and heat treatment and higher concentration of carbohydrate. [ABSTRACT FROM AUTHOR]

• Transcriptome profiles for Paulwonia terminal buds under different photoperiods provided evidence for the causes of terminal bud death and growth. • The genes of ABF, CYCD3, ERF1, and ARR-A are crucial for the regulation of terminal bud death. • TOC1 and LHY play an important role in the terminal bud growth of Paulwonia. The Paulownia is well-known for wood production and is called the tree of the future. A significant limitation of Paulownia cultivation is the "large crown and short stem" caused by the death of the terminal buds in autumn. In a previous study, we observed that the short day (SD, 8 h light and 16 h dark) results in the death of the terminal bud, whereas the long day (LD, 24 h light) results in sustained growth. To understand the molecular basis underlying this phenomenon, we conducted the RNA-Seq analysis of apical shoots in Paulownia under the SD and LD growth conditions for the three periods (2, 4, and 6 weeks). The metabolic pathways enrichment analysis was identified under the SD conditions, whereas the plant hormone signal transduction pathway plays an important regulatory role. After the cessation of growth, the ABF (a family of ABA-responsive element binding factors) in abscisic acid (ABA) signaling was downregulated. In addition, ERF1 in the ethylene (ETH) pathway, CYCD3 in the brassinosteroid (BR) pathway, and ARR-A in the cytokinin (CTK) pathway were upregulated. These may lead to reduced resistance of the terminal buds, continued cell division activity in the shoot apical meristem (SAM), and, ultimately, failure to form regular dormant buds. On the other hand, under LD conditions, TOC1 was upregulated, and LHYs were downregulated, along with genes involved in circadian rhythm, resulting in sustained growth. The findings help to elucidate the molecular mechanism of different photoperiods inducing terminal bud growth and death in the Paulownia species. [ABSTRACT FROM AUTHOR]

CuO Nanoparticles (CuO NPs) retard the plant growth but at appropriate concentration boosts shoot growth and therefore may function as nano-carrier or nano-fertilizer. To overcome the toxic effects, NPs can be capped with plant growth regulators. In this work, CuO-NPs (30 nm) were synthesized as the carrier and capped with indole-3-acetic acid (IAA) to generate CuO-IAA NPs (30.4 nm) as toxicity mitigant molecules. Seedlings of dicots, Lactuca sativa L. (Lettuce) were exposed to 5, 10 mg Kg−1/ of NPs in the soil to analyze shoot length, fresh and dry weight of shoots, phytochemicals, and antioxidant response. Toxicity to shoot length was recorded at higher concentrations of CuO-NPs, however, a reduction in toxicity was observed for CuO-IAA nanocomposite. Concentration-dependent decrease in the biomass of plants was also observed at higher concentrations of CuO-NPs (10 mg/kg). The antioxidative phytochemicals (phenolics and flavonoids) and antioxidative response increased in plants when exposed to CuO-NPs. However, the presence of CuO-IAA NPs combats the toxic response and a significant decrease in non-enzymatic antioxidants and total antioxidative response and total reducing power potential was observed. The results demonstrate that CuO-NPs can be used as a carrier of hormones for the enhancement of plant biomass and IAA on the surface of NPs reduces the toxic effects on NPs. • CuO-NPs capped with IAA were synthesized as carrier and toxicity mitigant, respectively. • Higher concentrations of NPs showed toxicity to shoot lengths. • Reduction in toxicity was observed for CuO-IAA nanocomposites. • Photochemical and antioxidant response increased upon exposure to CuO-NPs. • IAA on the surface of NPs reduces the toxic effects. [ABSTRACT FROM AUTHOR]

A healthy overall plant stature indispensably requires a firm base, and the root system must therefore be tolerant to low-temperature stress. The root system architecture is modulated by low-temperature stress, thereby affecting water and nutrient absorption. Phytohormone auxin and cytokinin signaling directly or indirectly regulate gravitropic response and root development during low-temperature stress. In addition, protective mechanisms during low-temperature stress-induced DNA damage in root stem cells involves auxin and cytokinin crosstalk. An interplay between auxin and cytokinin signaling in root tissue during low-temperature stress involving the activation or suppression of each other's signaling and transport cues, such as PIN proteins and the two-component system, determines the fate of root architecture and function. Low-temperature stress alters root system architecture. In particular, changes in the levels and response to auxin and cytokinin determine the fate of root architecture and function under stress because of their vital roles in regulating root cell division, differentiation, and elongation. An intricate nexus of genes encoding components of auxin and cytokinin biosynthesis, signaling, and transport components operate to counteract stress and facilitate optimum development. We review the role of auxin transport and signaling and its regulation by cytokinin during root development and stem cell maintenance under low-temperature stress. We highlight intricate mechanisms operating in root stem cells to minimize DNA damage by altering phytohormone levels, and discuss a working model for cytokinin in low-temperatures stress response. [ABSTRACT FROM AUTHOR]

Phytohormones are ubiquitous signaling molecules that regulate crucial aspects of plant growth, development, and environmental stress responses. Unraveling their functions and molecular mechanisms will help uncover how phytohormones balance plant growth and stress responses based on environmental cues. Comprehensively characterizing phytohormone levels and signaling network activities remains a major challenge. Technological improvements in mass spectrometry (MS) in terms of its resolution, mass accuracy and sensitivity have led to considerable biological advances. MS techniques are powerful, robust tools for uncovering phytohormone structures and signaling networks and mapping phytohormone-dependent protein interactions. Further developments in computational algorithms and multiomics approaches should provide new insights into the cooperation of these dynamic regulatory networks. Phytohormones have crucial roles in plant growth, development, and acclimation to environmental stress; however, measuring phytohormone levels and unraveling their complex signaling networks and interactions remains challenging. Mass spectrometry (MS) has revolutionized the study of complex biological systems, enabling the comprehensive identification and quantification of phytohormones and their related targets. Here, we review recent advances in MS technologies and highlight studies that have used MS to discover and analyze phytohormone-mediated molecular events. In particular, we focus on the application of MS for profiling phytohormones, elucidating phosphorylation signaling, and mapping protein interactions in plants. [ABSTRACT FROM AUTHOR]

• Members of Genus Paphiopedilum are categorised under rare and endangered of IUCN and CITES. • Conventional method of propagation is a slow process while the population of this species is reducing at an alarming rate in the wild. • Emphasis needs to be given on developing efficient protocols for in vitro mass multiplication to meet commercial and conservation strategies. • Significant observations on the response of the species on four types of cytokinins and auxins. • First report on the effect of Meta-topolin, IPA as phytohormones on growth and development of Paphiopedilum villosum. Paphiopedilum villosum Lindl. Stein , is a horticulturally important orchid as it is widely traded for its cut-flower and ornamental value, which is mainly attributed to long shelf-life of the flowers. High commercial demands of this genus have led to its extensive collection leading to the population diminution from the wild habitats. In vitro propagation technology is a prominent tool for multiplication of orchids for commercial and conservational purposes. In the present study, the effects of nutrient media composition and phytohormones in enhancing the shoot multiplication and seedling proliferation of P. villosum using in vitro technique was assessed. The optimal medium for shoot proliferation and root development was found to be Murashige and Skoog (MS, 1962) with the highest response of 70.8% in seedling development. Amongst the cytokinins, 10 µM meta -topolin (m T) supplemented in MS medium was found to be the most conducive for developing longest shoots (5.8 cm) and roots (4.5 cm). The auxin, indole-3-propionic acid (IPA) at 5 μM in MS medium resulted in 4.7 cm long shoots and 4.1 cm long roots. During acclimatization, the in vitro -raised seedlings showed 63.1% survival in compost mix substratum. The protocol described in the present study would be of immense importance in capping the over-exploitation of P. villosum from its natural habitat and to further enhance its large-scale propagation its large-scale propagation and conservation. [ABSTRACT FROM AUTHOR]

Salicylic acid (SA) is one of the potential plant growth regulators (PGRs) that regulate plant growth and development by triggering many physiological and metabolic processes. It is also known to be a crucial component of plant defense mechanisms against environmental stimuli. In stressed plants, it is documented that it can effectively modulate a myriad of metabolic processes including strengthening of oxidative defense system by directly or indirectly limiting the buildup of reactive nitrogen and oxygen radicals. Although it is well recognized that it performs a crucial role in plant tolerance to various stresses, it is not fully elucidated that whether low or high concentrations of this PGR is effective to achieve optimal growth of plants under stressful environments. It is also not fully understood that to what extent and in what manner it cross-talks with other potential growth regulators and signalling molecules within the plant body. Thus, this critical review discusses how far SA mediates crosstalk with other key PGRs and molecular components of signalling pathways mechanisms, particularly in plants exposed to environmental cues. Moreover, the function of SA exogenously applied in regulation of growth and development as well as reinforcement of oxidative defense system of plants under abiotic stresses is explicitly elucidated. • SA works with other plant hormones and signalling molecules to mitigate the effect of plant stress. • SA leads to increased H 2 O 2 to trigger varied processes to modulate the antioxidant status. • SA upraised GSH levels in heavy metal-stressed plants by regulating sequestration, making them nontoxic. • More research needs to be conducted to uncover the genetic network of SA. [ABSTRACT FROM AUTHOR]

Trypsin has a new activity of scavenging superoxide anion and generating hydrogen peroxide. Trypsin can significantly improve the storage quality of C. sativus. To illustrate the mechanism of trypsin-induced resistance in fruits and vegetables, an integrated analysis of widely targeted metabolomics and transcriptomics was carried out. Transcriptomic results showed that 1068 genes highly related to phenylpropanoid biosynthesis gathered in the brown module were obtained by WGCNA. In KEGG analysis, differentially expressed genes (DEGs) were also highly enriched in EIP (Environmental Information Processing) pathways "Plant hormone signal transduction (map04075)" and "MAPK signaling pathway-plant (map04016)". Next, 87 genes were identified as the leading edge by GSEA analysis. So far, CsMYC2 was highlighted as a key transcription factor that regulates phenylpropanoid biosynthesis identified by GSEA and WGCNA. Furthermore, the major route of biosynthesis of phenylpropanoid compounds including coumarins, lignins, chlorogenic acid, flavonoids, and derivatives regulated by trypsin was also illustrated by both transcriptomic and metabolomic data. Results of O2PLS showed that CsMYC2 was positively correlated with Rosmarinic acid-3-O-glucoside, Epigallocatechin, Quercetin-3-O-sophoroside (Baimaside), and so on. Correlation between CsMYC2, phenylpropanoid related genes, and metabolites in C. sativus was illustrated by co-expression networks. Roles of CsMYC2 were further checked in C. sativus by VIGS. The results of this study might give new insight into the exploration of the postharvest resistance mechanism of C. sativus induced by trypsin and provide useful information for the subsequent mining of resistance genes in C. sativus. [Display omitted] • CsMYC2 identified as a hub transcription factor responses to trypsin in C. sativus. • Route of phenylpropanoid biosynthesis regulated by CsMYC2 was rewired in C. sativus. • Trypsin induced C. sativus resistance through JA rather than ABA or other hormones. [ABSTRACT FROM AUTHOR]

The non-climacteric octoploid strawberry (Fragaria × ananassa Duchesne ex Rozier) was used as a model to study its regulation during fruit ripening. High performance liquid chromatography electrospray tandem-mass spectrometry (HPLC-ESI-MS/MS) was employed to profile 28 different endogenous phytohormones in strawberry. These include auxins, cytokinins (CKs), abscisic acid (ABA), ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), jasmonates, and phenolic compounds salicylic acid (SA), benzoic acid (BzA) and phenylacetic acid (PAA) together with their various metabolic forms that have remained largely unexplored thus far. ABA, ACC and CK N 6-(Δ2-isopentenyl)adenine (iP) were found to be associated with ripening while ABA catabolites 9-hydroxy-ABA and phaseic acid mimicked the pattern of climacteric decline at the turning phase of strawberry ripening. The content of other CK forms except iP decreased as fruit ripened, as also that of auxins indole-3-acetic acid (IAA) and oxo-IAA, and of jasmonates. Data presented here also suggest that both the transition and progression of strawberry fruit ripening are associated with N 6 -(Δ2-isopentenyl)adenosine-5′-monophosphate (iPRMP) → N 6 -(Δ2-isopentenyl)adenosine (iPR) → iP as the preferred CK metabolic pathway. In contrast, the ethylene precursor ACC was present at higher levels, with its abundance increasing from the onset of ripening to the red ripe stage. Further investigation of ripening-specific ACC accumulation revealed the presence of a large ACC synthase (ACS) encoding gene family in octoploid strawberry that was previously unknown. Seventeen ACS genes were found differentially expressed in fruit tissues, while six of them showed induced expression during strawberry fruit ripening. These data suggest a possible role(s) of ACC, ABA, and iP in strawberry fruit ripening. These data add new dimension to the existing knowledge of the interplay of different endogenous phytohormones in octoploid strawberry, paving the way for further investigation of their individual role(s) in fruit ripening. • Abundance of 28 endogenous phytohormones in six fruit stages of octoploid strawberry is presented. • Abscisic acid (ABA), 1-aminocyclopropane-1-carboxylic acid (ACC) and N 6-(Δ2-isopentenyl)adenine (iP) are positively associated with strawberry fruit ripening. • Cytokinin N 6 -(Δ2-isopentenyl) adenosine-5′-monophosphate (iPRMP).→ N 6 -(Δ2-isopentenyl) adenosine (iPR) → iP are identified and found associated with strawberry fruit ripening.. • Genome wide identification of 32 bonafide ACC synthase (ACS) genes were found associated with octoploid strawberry. • Expression of six ACS genes during strawberry fruit ripening corroborates with higher accumulation of ACC. [ABSTRACT FROM AUTHOR]

Xylogen-like arabinogalactan protein (XYLP) is an atypical lipid transport protein. In this study, 23 Phyllostachys edulis XYLPs were identified, and their proteins contain characteristic structures of AGP and nsLTP domain. All PeXYLPs can be divided into four clades, and their genes were unevenly distributed on 11 chromosome scaffolds. Collinear analysis revealed that segmental duplication was the main driver for PeXYLP family expansion. The c is-acting elements presented in the promoter are involved in various regulations of PeXYLPs expression. G.O. annotation revealed that PeXYLPs are mainly interested in lipid transport and synthesis and primarily function at the plasma membrane. Transcriptome analysis revealed that PeXYLPs were spatiotemporally expressed and displayed significant variability during various tissue development. Besides that, some PeXYLP s also respond to multiple phytohormones and abiotic stresses. By semi-quantitative RT-PCR, the response of some PeXYLPs to MeJA was confirmed, and the proteins were shown to localize to the plasma membrane mainly. WGCNA in defined regions of fast-growing bamboo shoots revealed that 5 PeXYLPs in 4 gene co-expression modules showed a positive module-trait relationship with three fast-growing regions. This systematic analysis of the PeXYLP family will provide a foundation for further insight into the functions of individual PeXYLP in a specific tissue or organ development, phytohormone perception, and stress responses in the future. • Twenty-three XYLP genes (PeXYLPs) were identified in the genome of Phyllostachys edulis and were classified into four evolutionary clades. • Segmental duplication plays a dominant role in expanding the PeXYLP family in Phyllostachys edulis. • Large-scale expansion of the XYLP family could have occurred after the segregation of monocotyledons and dicotyledons and then expanded independently. • Expression of some PeXYLP genes showed positive correlations with fast growth and elongation of internode in Phyllostachys edulis. [ABSTRACT FROM AUTHOR]

Fusarium fujikuroi is the microorganism that used for industrial production of gibberellic acids (GAs), a commercially very important plant hormone. A stable, high-yielding F. fujikuroi strain is essential for efficient bio-production. Although, there is a quick development in molecular tools and metabolic engineering research for this microbe in the past decade, the current industrially applying strains are mostly obtained from numerous rounds of mutagenesis and screening, while the industry is still dedicating in strain improvement work based mostly on this method. However, after over half a century's effort, the yield is still maintained at a low level today. We designed an efficient strategy for strain improvement by amphotericin B resistance prescreening and evolutionary engineering. A superior strain was obtained with over 25% increased yield after testing merely 640 isolates. The superior strain was later confirmed to be genetically very stable for GA production. Minimum inhibitory concentration (MIC) assay verified its increased resistance to amphotericin B, whose target ergosterol shares a same precursor with GAs. Decreased ergosterol accumulation indicated the increased GA 3 synthesis accompanied with attenuation of metabolic branch flux. In the end, we found the increased GA 3 titer of the superior strain also accompanied with faster growing biomass. [Display omitted] • An efficient screening-evolutionary engineering method has been developed for breeding of high GA yielding strains. • The average GA yield showed increasing tendency over the evolutionary engineering process. • The selected superior strain is genetically stable. • The selected superior strain has reduced metabolic branch flux of GAs. • The reduced metabolic branch flux of GAs corresponds to amphotericin B preliminary screening. [ABSTRACT FROM AUTHOR]

SHINE (SHN) clade transcription factors (TFs) represents a subfamily of APETALA2/ethylene-responsive factor (AP2/ERF) proteins. The latter, is characterized by its responsiveness to the phytohormone ethylene and the presence of AP2 DNA-binding domain. They are involved in many biological processes and in responses to different environmental constraints. SHN TFs were among the first identified regulators of cuticle formation. Cuticle plays crucial role in plant tolerance to drought, salinity and high temperature as well as in defense against pathogens. In addition, SHN were shown to be involved in the regulation of stomatal development which influences resistance to drought and diseases. Interestingly, recent studies have also shown that SHN TFs are involved in mediating the beneficial effects of arbuscular mycorrhizal fungi (AMF) as well as disease resistance conferred by nanoparticles. To fulfill their roles, SHN TFs are controlled upstream by other TFs and they control, in their turn, different downstream genes. In this review, we highlight the role of SHN TFs in different abiotic and biotic stresses through their involvement in cuticle biosynthesis, stomatal development and molecular regulation of biochemical and physiological traits. In addition, we discuss the regulation of SHN TFs by plant hormones and their influence on hormone biosynthesis and signaling pathways. Knowledge of this complex regulation can be put into contribution to increase multiple abiotic stress tolerances through transgenesis, gene editing and classical breeding. • SHINE (SHN) clade role in development and abiotic and biotic stress responses is focused on. • SHN clade is regulated upstream by different transcription factors and regulates, in its turn, downstream genes. • SHN clade is involved in beneficial effects conferred by nanoparticles and arbuscular mycorrhizal fungi. • SHN clade is a promising candidate for improvement of multiple stresses without yield penalty. [ABSTRACT FROM AUTHOR]

In 1998, Bill Gray and colleagues showed that warm temperatures trigger arabidopsis hypocotyl elongation in an auxin-dependent manner. This laid the foundation for a vibrant research discipline. With several active members of the 'thermomorphogenesis' community, we here reflect on 25 years of elevated ambient temperature research and look to the future. [ABSTRACT FROM AUTHOR]

High temperatures cause physiological and biochemical changes and significantly affect young panicle development of rice (Oryza sativa L.). Brassinosteroids play important roles in enhancing crop stress resistance. In this study, we subjected rice cultivars Huanghuazhan (heat-resistant) and IR36 (heat-sensitive) to high temperature (HT, 40 ºC) or normal temperature (NT, 33 ºC) for 7 d at the panicle initiation stage, in conjunction with application of 24-epibrassinolide [EBR, a synthetic brassinolide (BR)] or brassinazole (BRZ, a BR biosynthesis inhibitor) at the beginning of the treatments. HT exacerbated spikelet degeneration and inhibited young panicle growth, which were partially prevented by EBR application, while BRZ application aggravated the reduction in spikelet number. HT decreased the contents of BR, active cytokinins (aCTK), active gibberellins (aGA) and indole-3-acetic acid (IAA), but increased the content of abscisic acid (ABA) in young panicles. The activities of key enzymes involved in sucrose hydrolysis, glycolysis and the tricarboxylic acid cycle in young panicles were decreased with the change of endogenous hormone levels under HT. In addition, the contents of H 2 O 2 and malondialdehyde (MDA) were increased and the activities of antioxidant enzymes were decreased in young panicles. Exogenous application of EBR induced the expression of phytohormone biosynthesis-related genes and down-regulated the expression of phytohormone catabolism-related genes to increase the contents of endogenous BR, aCTK, aGA and ABA, thus promoting the decomposition and utilization of sucrose in young panicles, enhancing the activities of superoxide dismutase, catalase and peroxidase, and reducing the accumulation of H 2 O 2 and MDA in young panicles, whereas application of BRZ had the opposite physiological effects. These results showed that brassinosteroids mediate endogenous phytohormone metabolism to alleviate HT injury at the panicle initiation stage in rice. [ABSTRACT FROM AUTHOR]

Consistent climatic perturbations have increased global environmental concerns, especially the impacts of abiotic stresses on crop productivity. Rice is a staple food crop for the majority of the world's population. Abiotic stresses, including salt, drought, heat, cold and heavy metals, are potential inhibitors of rice growth and yield. Abiotic stresses elicit various acclimation responses that facilitate in stress mitigation. Plant hormones play an important role in mediating the growth and development of rice plants under optimal and stressful environments by activating a multitude of signalling cascades to elicit the rice plant's adaptive responses. The current review describes the role of plant hormone-mediated abiotic stress tolerance in rice, potential crosstalk between plant hormones involved in rice abiotic stress tolerance and significant advancements in biotechnological initiatives including genetic engineering approach to provide a step forward in making rice resistance to abiotic stress. [ABSTRACT FROM AUTHOR]

Dormancy is an adaptation mechanism of plants to environmental stress. Myricaria laxiflora undergoes a long period of flooding stress every year. In order to determine whether this species escapes flooding stress through dormancy, young branches and leaves were collected at different time points before the onset of flooding, and changes in the content/activity of hormones/enzymes that are closely involved in plant growth were monitored. The inducing environmental factors of summer dormancy were identified. The branches and leaves of M. laxiflora showed the following trends as summer flooding approached: (1) gradual increase in the abscisic acid content; (2) gradual decrease in the gibberellin and cytokinin contents; and (3) a continuous decrease in the activities of malate dehydrogenase (MDH), ribulose diphosphate carboxylase (RuBisCo), and glycolate oxidase (GLO). Pearson correlation analysis revealed (1) daylight duration was highly correlated with the hormone content and enzyme activity; (2) the daily mean air temperature (DMAT) was significantly correlated with the cytokinin content. These findings suggest that daylight duration was the main environmental factor leading to changes in the phytohormone content and enzyme activity as well as leading to summer dormancy. M. laxiflora undergoes dormancy before the onset of summer flooding to escape summer flooding stress. Our data indicate that summer flooding does not impede the survival and growth of M. laxiflora. • The content of abscisic acid increased with the approach of summer flooding. • The content of cytokinin, gibberellin and enzymes decreased. • Change of daylight duration induced the variation of phytohormone and enzyme content. • M. laxiflora undergoes dormancy induced by daylight duration before summer flooding. [ABSTRACT FROM AUTHOR]

• SOS pathway is a major pathway triggered by Ca2+ under salt stress. • Silicon has a role in the improved functioning of the SOS pathway under salt stress. • Calcium signalling and ABA synthesis results in stomatal closure. • High cytosolic Ca2+ results in upregulating ROS production. Owing to the sessile nature of plants, they are at the mercy of environmental conditions and are often subject to severe abiotic stresses. Amongst these abiotic stresses, high salinity stress is one of the most common and severe stresses affecting one-third of irrigated agricultural lands worldwide. Calcium ion is well known for its essential role as a mediator of signals and in regulating and specifying the cellular responses to abiotic stresses. To adapt to salt stress, one of the main strategies developed by plants is calcium signalling responses. The excess extracellular salt is detected by specific root receptors and resulted in immediate rise of cytosolic free Ca2+. Exhaustive research has been conducted to identify the genetic identities of Ca2+channels and signalling factors, developing novel findings on such tolerance mechanisms in plants. However, the complex interconnected system of the salinity stress response by Ca2+signalling in plants has not been adequately justified. Plants employ a combination of Ca2+ integrated proteins, phytohormones, osmolytes, receptors and other signalling factors in response to salinity stress, making this a complex calcium response network. In this review, we summarise and discuss the role of calcium signalling in response to salinity stress. In contrast to other studies, we try to provide a holistic overview of both chemical and mechanical processes involved in salt stress response while expanding on gaps filled by recent research. Furthermore, based on existing knowledge, we evaluate the different types of mechanisms and pathways through which calcium signalling works. [ABSTRACT FROM AUTHOR]

[Display omitted] • Transcriptional mechanism of tobacco seed deterioration was revealed by small RNA and transcriptome sequencing. • The cleavage relationship between tobacco miRNA and mRNA was validated by degradome sequencing. • Coherent miRNA-mRNA pairs of seed deterioration were screened through combined analysis. • Rice homologous target genes found that OsARF18 and OsMBD707 were functional in seed deterioration. • Transcriptional multiomics provides substantial transcriptional data regarding seed deterioration for further study. Mature seeds deteriorate gradually and die eventually during long-term storage. Controlled deterioration is often used to accelerate the seed deterioration rate to assess the seed vigor and physiological quality of seed lots. Although it is well known that the process of seed deterioration produced by controlled deterioration is distinct from that caused by long-term storage, the differences in transcriptional levels have not been reported. Clarifying the mechanism of seed deterioration is critical for identifying, conserving and utilizing germplasm resources. Tobacco (Nicotiana tabacum L.) seeds were studied thoroughly using transcriptome, small RNA, and degradome sequencing after long-term storage (LS) and controlled deterioration (CD). Co-expression trend analysis identified transcripts involved in tobacco seed deterioration, while phylogenetic analysis helped to uncover comparable targets in rice (Oryza sativa L.) for further verification and utilization. In LS and CD, a total of 2,112 genes and 164 miRNAs were differentially expressed, including 20 interaction miRNA-mRNA pairs with contrasting expression. Transcriptional multiomics found that the main causes of LS were plant hormone signal transduction and protein processing in the endoplasmic reticulum, whereas the primary cause of CD was nucleotide excision repair dysfunction. The homeostatic balance of RNA degradation and the spliceosome occurred in both modes of seed deterioration. Additionally, co-expression trend analysis identified two coherent pairs, nta-miR160b - NtARF18 and nta-miR396c - NtMBD10 , as being significant in LS and CD, respectively. For utilization, rice homologous targets OsARF18 and OsMBD707 were verified to play similar roles in LS and CD, respectively. This study demonstrated the transcriptional mechanism of tobacco and key genes in seed deterioration. And the application of key genes in rice also verified the feasibility of the multiomics method, guiding the identification of candidate genes to precisely delay seed deterioration in other species of seed research. [ABSTRACT FROM AUTHOR]

[Display omitted] • Topping promotes the outgrowth of citrus axillary bud through regulating the metabolism and signal transduction of auxin, cytokinin and abscisic acid. • The promotion of citrus axillary bud outgrowth by topping may be attributed to more sugar transport to axillary bud and signal transduction of Tre6P, glycolysis /tricarboxylic acid cycle. • Some transcription factors, such as MYB, Cyclin_c and AP2/ERF, may be involved in citrus axillary bud outgrowth. Topping, an important tree shaping and pruning technique, can promote the outgrowth of citrus axillary buds. However, the underlying molecular mechanism is still unclear. In this study, spring shoots of Citrus reticulata 'Huagan No.2′ were topped and transcriptome was compared between axillary buds of topped and untopped shoots at 6 and 11 days after topping (DAT). 1944 and 2394 differentially expressed genes (DEGs) were found at 6 and 11 DAT, respectively. KEGG analysis revealed that many DEGs were related to starch and sucrose metabolism, signal transduction of auxin, cytokinin and abscisic acid. Specially, transcript levels of auxin synthesis, transport, and signaling-related genes (SAURs and ARF5), cytokinin signal transduction related genes (CRE1, AHP and Type-A ARRs) , ABA signal responsive genes (PYL and ABF) were up-regulated by topping; while transcript levels of auxin receptor TIR1 , auxin responsive genes AUX/IAAs , ABA signal transduction related gene PP2Cs and synthesis related genes NCED3 were down-regulated. On the other hand, the contents of sucrose and fructose in axillary buds of topped shoots were significantly higher than those in untopped shoots; transcript levels of 16 genes related to sucrose synthase, hexokinase, sucrose phosphate synthase, endoglucanase and glucosidase, were up-regulated in axillary buds after topping. In addition, transcript levels of genes related to trehalose 6-phosphate metabolism and glycolysis/tricarboxylic acid (TCA) cycle, as well to some transcription factors including Pkinase, Pkinase_Tyr, Kinesin, AP2/ERF, P450, MYB, NAC and Cyclin_c, significantly responded to topping. Taken together, the present results suggested that topping promoted citrus axillary bud outgrowth through comprehensively regulating plant hormone and carbohydrate metabolism, as well as signal transduction. These results deepened our understanding of citrus axillary bud outgrowth by topping and laid a foundation for further research on the molecular mechanisms of citrus axillary bud outgrowth. [ABSTRACT FROM AUTHOR]

Sugar signal mediated by Cell wall invertase (CWIN) plays a central role in seed development. In higher plants, invertase inhibitors (INHs) suppress CWIN activities at a post-translational level. In Litchi chinensis cultivar 'Nuomici', impaired CWIN expression is associated with seed abortion. Here, the expression of LcINH1 was significantly higher in the funicle of seed-aborting cultivar 'Nuomici' than big-seeded cultivar 'Heiye'. Promoter analyses found LcINH1 contained a 404 bp repeat fragment with an endosperm regulatory element of Skn-1_motif. LcINH1 and LcCWIN2/5 were located in plasma membrane. LcINH1 was able to interact with LcCWIN5, but not with LcCWIN2. In vitro enzyme activity assay demonstrated that LcINH1 could inhibit CWIN activity. Silencing LcINH1 in 'Nuomici' resulted in normal seed development, paralleled increased CWIN activities and glucose levels. Transcriptome analysis identified 1079 differentially expressed genes (DEGs) in LcINH1 -silenced fruits. KEGG analysis showed significant enrichment of DEGs in pathways related to transporters and plant hormone signal transduction. Weighted gene co-expression network analysis indicated that the turquoise module was highly correlated with fructose content, and LcSWEET3b was closely associated with early seed development. These findings suggest that LcINH1 regulate LcCWIN5 activity at the post-translational level to alter sucrose metabolism, thereby affecting early seed development in litchi. [ABSTRACT FROM AUTHOR]

Nowadays, improving the quality of postharvest fruits has become a hot research topic. Nitric oxide (NO) is often regarded as a signaling molecule that delays the postharvest senescence of fruits. Moreover, phytohormones affect the postharvest senescence of fruits. This review mainly describes how NO improves the postharvest quality of fruits by delaying postharvest fruit senescence, mitigating fruit cold damage and controlling postharvest diseases. Furthermore, the crosstalk of NO and multiple plant hormones effectively delays the postharvest senescence of fruits, and the major crosstalk mechanisms include (1) mediating phytohormone signaling. (2) inhibiting ETH production. (3) stimulating antioxidant enzyme activity. (4) decreasing membrane lipid peroxidation. (5) maintaining membrane integrity. (6) inhibiting respiration rate. (7) regulating gene expression related to fruit senescence. This review concluded the roles and mechanisms of NO in delaying postharvest fruit senescence. In addition, the crosstalk mechanisms between NO and various phytohormones on the regulation of postharvest fruit quality are also highlighted, which provides new ideas for the subsequent research. • Nitric oxide effectively delays postharvest fruit senescence. • Nitric oxide interacts with phytohormones to improve fruit quality. • Nitric oxide reduces fruit cold damage and enhances disease resistance during postharvest. [ABSTRACT FROM AUTHOR]

Pruning is a vital agronomic strategy in the cultivation and management of tea trees, greatly affecting the growth of tea trees. In this study, the effect of pruning on tea tree growth was analyzed from transcriptome and hormone metabolome perspectives. The study concluded that pruned (SX) tea trees showed significant increases in leaf area, hundred bud weight, and yield, which were 31.82 %, 36.05 %, and 72.73 %, respectively, compared to unpruned (SC) tea trees. Analysis of gene differential expression and KEGG pathway enrichment showed that 1246 genes characterized by significant differences between SC and SX were significantly enriched in seven pathways, namely plant hormone signal transduction (ko04075), MAPK signaling pathway-plant (ko04016), biosynthesis of secondary metabolites (ko01110), plant-pathogen interaction (ko04626), alpha-linolenic acid metabolism (ko00592), metabolic pathways (ko01100), and ABC transporters (ko02010). Where all of the above pathways were significantly higher in SX than in SC, except for plant-pathogen interaction pathway. Analysis of hormone content showed that SX (21.53 ppm) had significantly higher hormone content than SC (18.85 ppm). Further analysis showed that six characteristic hormones differed significantly in SX, including significantly increased contents of L-phenylalanine and N-6-iso-pentenyladenosine-5′-monophosphate (iPAMP), and significantly decreased contents of indole, abscisic acid, jasmonoyl-L-isoleucine, and 12-hydroxyjasmonic acid in SX. In conclusion, the results showed that pruning stimulated gene expression of the ko04016 pathway, enhanced the strength of the ko01100 and ko01110 pathways, and increased the metabolism of the ko04075, ko00592, and ko02010 pathways, which then led to the increase of L-phenylalanine and iPAMP contents, and promoted tea tree growth. This study provides valuable insight into the importance of cultivating and managing tea trees, particularly those that have undergone pruning procedures. [Display omitted] • Pruning is an agronomic strategy that has a great impact on the growth of tea trees. • Pruning enhances gene expression of hormone signaling pathways in tea trees. • Pruning promotes the growth of tea trees by increasing the content of two hormones. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phytohormones in cells of IZ and strain 3005 are different at different temperatures. • Elevated endogenous JA in wild-type algae under high temperature conditions. • IBU can enhance the high-temperature tolerance and antioxidant activity of IZ. • IBU upregulate genes involved in the photosynthesis pathway of strain IZ. Phytohormones play a role in regulating microalgae cells tolerance to adversity. This paper examines the effects of different temperatures (20 °C, 25 °C, 30 °C and 35 °C) on the physiological characteristics and endogenous phytohormones of the Isochrysis Zhanjiangensis (IZ) and its mutagenic strain (3005). The results showed that the endogenous phytohormones indole acetic acid (IAA) and jasmonic acid (JA) exhibited significant differences (P <0.05) between the two strains. The addition of 0.5 mg·L-1 exogenous JA inhibitor ibuprofen (IBU) improved cell growth of IZ, and was extremely effective in the accumulation of polysaccharides, which accounted for 33.25 %. Transcriptomic analyses revealed that genes involved in photosynthesis, such as PetC and PsbO, exhibited significantly elevated expression of the strain IZ, while the pathways related to JA synthesis may be the factor affecting microalgae temperature tolerance. This study provides a theoretical foundation for elucidating the underlying mechanisms and potential applications for high temperature tolerance in IZ. [ABSTRACT FROM AUTHOR]

Plant hormones activate receptors, initiating intracellular signaling pathways. Eventually, hormone-specific transcription factors become active in the nucleus, facilitating hormone-induced transcriptional regulation. Chromatin plays a fundamental role in the regulation of transcription, the process by which genetic information encoded in DNA is converted into RNA. The structure of chromatin, a complex of DNA and proteins, directly influences the accessibility of genes to the transcriptional machinery. The different signaling pathways and transcription factors involved in the transmission of information from the receptors to the nucleus have been readily explored, but not so much for the specific mechanisms employed by the cell to ultimately instruct the chromatin changes necessary for a fast and robust transcription activation, specifically for plant hormone responses. In this review, we will focus on the advancements in understanding how chromatin receives plant hormones, facilitating the changes necessary for fast, robust, and specific transcriptional regulation. [ABSTRACT FROM AUTHOR]