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The plant hormone ABA (abscisic acid) plays an extremely important role in plant growth and adaptive stress, including but are not limited to seed germination, stomatal closure, pathogen infection, drought and cold stresses. Reactive oxygen species (ROS) are response molecules widely produced by plant cells under biotic and abiotic stress conditions. The production of apoplast ROS is induced and regulated by ABA, and participates in the ABA signaling pathway and its regulated plant immune system. In this review, we summarize ABA and ROS in apoplast ROS production, plant response to biotic and abiotic stresses, plant growth regulation, ABA signal transduction, and the regulatory relationship between ABA and other plant hormones. In addition, we also discuss the effects of protein post-translational modifications on ABA and ROS related factors. [ABSTRACT FROM AUTHOR]

A tobacco chloroplast hypothetical open reading frame 4 (YCF4) has been reported as a non-essential assembly factor for photosynthesis based on an incomplete knockout of YCF4, just 93 of 184 amino acids from the N-terminus were knocked out. On the other hand, we removed the complete sequence of YCF4 from tobacco chloroplasts and observed that DYCF4 plants were unable to survive photoautotrophically as their growth was hampered in the absence of an external carbon supply, clearly showing that the YCF4 is essential for photosynthesis. Initially, the aadA gene was introduced into the tobacco plastome replacing the complete YCF4 gene through homologous recombination events. The replacement of YCF4 with aadA was confirmed by PCR and Southern blot analysis in DYCF4 plants. Homoplasmic DYCF4 plants had a light green phenotype, and the leaves became pale yellow as the plants grew older. The structure of chloroplasts of DYCF4 mutants of light green phenotype was studied using a transmission electron microscope (TEM), and the micrographs demonstrated structural anomalies in the chloroplasts; including shape, size, and grana stacking compared to the wild-type plants. Further, transcriptome analysis revealed that the expression of PSI, PSII, and ribosomal genes remained unchanged in ΔYCF4 plants. On the other hand, transcriptome levels of rbcL (Ribulose 1,5-bisphosphate carboxylase/oxygenase large subunit), LHC (Light-Harvesting Complex), and ATP Synthase (atpB and atpL) decreased, indicating that the YCF4 has the function(s) in addition to assembling the photosynthetic complex. This was confirmed by in-silico protein-protein interactions of full-length YCF4 as well as 93 and 91 of 184 amino acids from N- and C-termini of the full-length protein, which revealed that the C-terminus (91 aa) of YCF4 is important in interacting with other chloroplast proteins. These findings provide genetic support for the plastid YCF4 gene's critical role in regulating the plastid gene expression and assembling the photosynthetic complex. [ABSTRACT FROM AUTHOR]

Soil salinity is a major constraint adversely affecting agricultural crops including wheat worldwide. The use of plant growth promoting rhizobacteria (PGPR) to alleviate salt stress in crops has attracted the focus of many researchers due to its safe and eco-friendly nature. The current study aimed to study the genetic potential of high halophilic Bacillus strains, isolated from the rhizosphere in the extreme environment of the Qinghai–Tibetan plateau region of China, to reduce salt stress in wheat plants. The genetic analysis of high halophilic strains, NMCN1, LLCG23, and moderate halophilic stain, FZB42, revealed their key genetic features that play an important role in salt stress, osmotic regulation, signal transduction and membrane transport. Consequently, the expression of predicted salt stress-related genes were upregulated in the halophilic strains upon NaCl treatments 10, 16 and 18%, as compared with control. The halophilic strains also induced a stress response in wheat plants through the regulation of lipid peroxidation, abscisic acid and proline in a very efficient manner. Furthermore, NMCN1 and LLCG23 significantly enhanced wheat growth parameters in terms of physiological traits, i.e., fresh weight 31.2% and 29.7%, dry weight 28.6% and 27.3%, shoot length 34.2% and 31.3% and root length 32.4% and 30.2%, respectively, as compared to control plants under high NaCl concentration (200 mmol). The Bacillus strains NMCN1 and LLCG23 efficiently modulated phytohormones, leading to the substantial enhancement of plant tolerance towards salt stress. Therefore, we concluded that NMCN1 and LLCG23 contain a plethora of genetic features enabling them to combat with salt stress, which could be widely used in different bio-formulations to obtain high crop production in saline conditions. [ABSTRACT FROM AUTHOR]

Autophagy is a highly conserved self-degradation mechanism in eukaryotes. Excess or harmful intracellular content can be encapsulated by double-membrane autophagic vacuoles and transferred to vacuoles for degradation in plants. Current research shows three types of autophagy in plants, with macroautophagy being the most important autophagic degradation pathway. Until now, more than 40 autophagy-related (ATG) proteins have been identified in plants that are involved in macroautophagy, and these proteins play an important role in plant growth regulation and stress responses. In this review, we mainly introduce the research progress of autophagy in plant vegetative growth (roots and leaves), reproductive growth (pollen), and resistance to biotic (viruses, bacteria, and fungi) and abiotic stresses (nutrients, drought, salt, cold, and heat stress), and we discuss the application direction of plant autophagy in the future. [ABSTRACT FROM AUTHOR]

C2H2 zinc finger (C2H2-ZF) transcription factors participate in various aspects of normal plant growth regulation and stress responses. C1-2i C2H2-ZFs are a special subclass of conserved proteins that contain two ZnF-C2H2 domains. Some C1-2i C2H2-ZFs in Arabidopsis (ZAT) are involved in stress resistance and other functions. However, there is limited information on C1-2i C2H2-ZFs in Populus trichocarpa (PtriZATs). To analyze the function and evolution of C1-2i C2H2-ZFs, eleven PtriZATs were identified in P. trichocarpa, which can be classified into two subgroups. The protein structure, conserved ZnF-C2H2 domains and QALGGH motifs, showed high conservation during the evolution of PtriZATs in P. trichocarpa. The spacing between two ZnF-C2H2 domains, chromosomal locations and cis-elements implied the original proteins and function of PtriZATs. Furthermore, the gene expression of different tissues and stress treatment showed the functional differentiation of PtriZATs subgroups and their stress response function. The analysis of C1-2i C2H2-ZFs in different Populus species and plants implied their evolution and differentiation, especially in terms of stress resistance. Cis-elements and expression pattern analysis of interaction proteins implied the function of PtriZATs through binding with stress-related genes, which are involved in gene regulation by via epigenetic modification through histone regulation, DNA methylation, ubiquitination, etc. Our results for the origin and evolution of PtriZATs will contribute to understanding the functional differentiation of C1-2i C2H2-ZFs in P. trichocarpa. The interaction and expression results will lay a foundation for the further functional investigation of their roles and biological processes in Populus. [ABSTRACT FROM AUTHOR]

Background. Alfalfa (Medicago sativa L.) is a kind of forage with high relative feeding value in farming and livestock breeding, and is of great significance to the development of animal husbandry. The growth of the aboveground part of alfalfa is an important factor that limits crop yield. Clarifying the molecular mechanisms that maintain vigorous growth in alfalfa may contribute to the development of molecular breeding for this crop. Methods. Here, we evaluated the growth phenotypes of five cultivars of alfalfa (WL 712, WL 525HQ, Victoria, Knight 2, and Aohan). Then RNA-seq was performed on the stems of WL 712, chosen as a fast growing cultivar, and Aohan, chosen as a slow growing cultivar. GO enrichment analysis was conducted on all differentially expressed genes (DEGs). Result. Among the differentially expressed genes that were up-regulated in the fast growing cultivar, GO analysis revealed enrichment in the following seven categories: formation of water-conducting tissue in vascular plants, biosynthesis and degradation of lignin, formation of the primary or secondary cell wall, cell enlargement and plant growth, cell division and shoot initiation, stem growth and induced germination, and cell elongation. KEGG analysis showed that differentially expressed genes were annotated as being involved in plant hormone signal transduction, photosynthesis, and phenylpropanoid biosynthesis. KEGG analysis also showed that up-regulated in the fast growing cultivar were members of the WRKY family of transcription factors related to plant growth and development, members of the NAC and MYB gene families related to the synthesis of cellulose and hemicellulose, and the development of secondary cell wall fibres, and finally, MYB family members that are involved in plant growth regulation. Our research results not only enrich the transcriptome database of alfalfa, but also provide valuable information for explaining the molecular mechanism of fast growth, and can provide reference for the production of alfalfa. [ABSTRACT FROM AUTHOR]

Copyright of Anadolu Tarım Bilimleri Dergisi is the property of Ondokuz Mayis Universitesi, Ziraat Fakultesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Drought is one of the most important factors that limit crop yield. In this study, the growth promotive activity of terrein, a microbial metabolite, on four selected agricultural plants (Vigna radiata, Brassica chinensis, Triticum aestivum and Sorghum bicolor) under drought conditions was assessed via pot experiment. Terrein effectively stimulated the seedling growth of tested species and increased their fresh and dry weight at low concentrations (2 and 10 μg/mL), either applied as a seed soaking agent or a spray solution, especially on root growth. The maximum stimulatory effect on root growth was observed on B. chinensis seedlings (99.20%), on fresh weight was found on T. aestivum seedlings (97.23%), and on dry weight was discovered on V. radiata seedlings (58.33%), implying that this stimulatory effect was species-specific. Further study revealed that the application of terrein significantly raised the contents of GA3, IAA and CTK; meanwhile, MDA content declined significantly, whereas the activity of POD, CAT and SOD was boosted significantly, suggesting that terrein can stimulate plant growth by reducing the production of ROS. Our work is the first study focusing on terrein’s plant growth promotive activity, indicating terrein has the potential to be further explored as an environment-friendly growth regulator.

The article discusses the process of somatic embryogenesis, which involves regenerating whole plants from cultured somatic cells. The researchers focused on the effectiveness of the synthetic auxin 2,4‐dichlorophenoxyacetic acid (2,4‐D) in inducing somatic embryogenesis and found that it accumulates to higher levels within plant cells and exhibits lower efficiency as a substrate for auxin efflux carriers compared to other auxins. They also discovered that inhibiting auxin efflux enhances the effectiveness of natural auxins in somatic embryogenesis. The researchers suggest that using efflux-inhibited natural auxins instead of 2,4-D could lead to substantial improvements in plant regeneration procedures. [Extracted from the article]

Arabidopsis cyclic nucleotide-gated channels (CNGC) 2 and 4 are shown to negatively regulate disease resistance and heat tolerance and to positively regulate plant growth. Whether or not their functions in these processes are interdependent is largely unknown. Here, using the mutation of phytoalexin deficient 4 (PAD4) to inhibit the enhanced defense response and programmed cell death (PCD), we assessed the contribution of the altered defense response to the heat tolerance and plant growth in the cngc2 and cngc4 single and double mutants. The pad4 mutation reverted the enhanced disease resistance of the cngc2 and cngc4 mutants at the normal temperature (22 °C) but not at the elevated temperature (28 °C). The pad4 mutation slightly alleviated the dwarfism of the cngc2 and cngc4 mutants at 22 °C but not at 28 °C, indicating a small contribution from the defense response to plant growth regulation. The pad4 mutation also reduced the enhanced heat tolerance in the cngc mutants, suggesting an involvement of PCD in heat tolerance. In addition, a higher heat tolerance was correlated with more opened stomata under heat treatment among the wild type and mutants of the PAD4, CNGC2 and CNGC4 genes. In sum, this study suggests that the regulation of heat tolerance and plant growth by CNGC2 and CNGC4 is almost independent of their regulation of disease resistance. It also reveals a PAD4-dependent role of CNGC2 and CNGC4 in stomatal aperture regulation and heat tolerance. [ABSTRACT FROM AUTHOR]

The red alga Neopyropia yezoensis undergoes polarized elongation and asymmetrical cell division of the apical stem cell during tip growth in filamentous generations of its life cycle: the conchocelis and conchosporangium. Side branches are also produced via tip growth, a process involving the regeneration and asymmetrical division of the apical stem cell. Here, we demonstrate that auxin plays a crucial role in these processes by using the auxin antagonist 2-(1H-Indol-3-yl)-4-oxo-4-phenyl-butyric acid (PEO-IAA), which specifically blocks the activity of the auxin receptor TRANSPORT INHIBITOR RESPONSE1 (TIR1) in land plants. PEO-IAA repressed both the regeneration and polarized tip growth of the apical stem cell in single-celled conchocelis; this phenomenon was reversed by treatment with the auxin indole-3-acetic acid (IAA). In addition, tip growth of the conchosporangium was accelerated by IAA treatment but repressed by PEO-IAA treatment. These findings indicate that auxin regulates polarized tip cell growth and that an auxin receptor-like protein is present in N. yezoensis. The sensitivity to different 5-alkoxy-IAA analogs differs considerably between N. yezoensis and Arabidopsis thaliana. N. yezoensis lacks a gene encoding TIR1, indicating that its auxin receptor-like protein differs from the auxin receptor of terrestrial plants. These findings shed light on auxin-induced mechanisms and the regulation of tip growth in plants. [ABSTRACT FROM AUTHOR]

Cys2/His2-type Zinc Finger Proteins (C2H2-ZFPs) are known to play vital roles in the regulation of growth and development in plants. Nevertheless, the underlying molecular network is yet to be established. In this review paper, we elaborate on the structure, classification and biological functions of C2H2-ZFPs, and focus on the molecular mechanism of C2H2-ZFPs in regulating plant growth and development, to provide theoretical support for crop cultivation and breeding. [ABSTRACT FROM AUTHOR]

The article presents alternatives for the use of additional components of cultivation technology for lentil that are aimed at increasing tolerance to a water deficiency at the early stages of growth and development, namely: (i) soil amendment with moisture-retaining polymers; (ii) seed treatment with a growth regulator contributing to a better formation of the root system; (iii) the use of biological product providing for the formation of the soil mycorrhizal biota; and (iv) foliar application of micro fertilizers. The best in terms of the effect on the growth and development of plants appeared the following treatments: seed treatment with the growth regulator Kelpak SC (3 l/t), soil amendment with moisture-retaining polymers Aquasorb (200 kg/ha) and mycorrhizal bio preparation Mycofriend (1 l/ha), followed by the treatment of plants with micro fertilizer Reakom-SP-Legumes (3 l/ha, BBCH 14) or Quantum-Legumes (1.0 l/ha, BBCH 14). These treatments contributed to an increase in the number of stems of the 2nd and 3rd orders by 1.8 and 2.0, leaves by 8.6 and 8.8, and nods by 15.3 and 16.1, respectively, compared to the control treatment. In addition, a combination of these plant products had a positive impact on the formation of filled beans, and the plants formed 23.5−23.7 filled beans. Also, these treatments provided 1.6−1.8 times increase in the number of seeds per bean compared to the control. Pre-sowing seed treatment with the growth regulator Kelpak SC (3 l/t), application of moisture-retaining polymers Aquasorb (200 kg/ha) and mycorrhizal bio preparation Mycofriend (1 l/ha), followed by foliar application of fertilizers Reakom SC Legumes (3 l/ha, BBCH 14) or Quantum-Legumes (1.0 l/ha, BBCH 14) contributed to the formation of lentil yield of 3.15 and 3.17 t/ha, respectively, over the years of the experiment. The integral action of these plant products contributed to obtaining seeds with a higher content of proteins, fats, and carbohydrates, as well as vitamins, macro and microelements. Moreover, young lentil sprouts can resist adverse environmental factors due to the richer biochemical stocks formed in a seed. [ABSTRACT FROM AUTHOR]

As the most prevalent epi-transcriptional modification, m6A modifications play essential roles in regulating RNA fate. The molecular functions of YTH521-B homology (YTH) domain proteins, the most known READER proteins of m6A modifications, have been well-studied in animals. Although plants contain more YTH domain proteins than other eukaryotes, little is known about their biological importance. In dicot species Arabidopsis thaliana, the YTHDFA clade members ECT2/3/4 and CPSF30-L are well-studied and important for cell proliferation, plant organogenesis, and nitrate transport. More emphasis is needed on the biological functions of plant YTH proteins, especially monocot YTHs. Here we presented a detailed phylogenetic relationship of eukaryotic YTH proteins and clustered plant YTHDFC clade into three subclades. To determine the importance of monocot YTH proteins, YTH knockout mutants and RNAi-induced knockdown plants were constructed and used for phenotyping, transcriptomic analysis, and stress treatments. Knocking out or knocking down OsYTHs led to the downregulation of multicellular organismal regulation genes and resulted in growth defects. In addition, loss-of-function ythdfa mutants led to better salinity tolerance whereas ythdfc mutants were more sensitive to abiotic stress. Overall, our study establishes the functional relevance of rice YTH genes in plant growth regulation and stress response. [ABSTRACT FROM AUTHOR]

The extensive use of synthetic chemical fertilizers is associated with environmental pollution and soil degradation. In addition, the high costs of these fertilizers necessitate the search for alternative, eco-friendly and safe natural sources of phytonutrients. The liquid extracted from moringa (Moringa oleifera Lam.) leaves has been used in agriculture to improve the growth and productivity of several crops. The efficacy of moringa leaf extract (MLE) is attributed to its high content of mineral nutrients, protein, vitamins, sugars, fiber, phenolics and free proline. In addition, MLE contains significant amounts of phytohormones, such as auxins, cytokinins and gibberellins. Furthermore, MLE is a valuable product promoting seed germination, plant growth and deeper root development, delaying fruit senescence and increasing the yield and quality of crops grown under normal or stressful conditions. Here, we review the research on MLE as a biostimulant to enhance crop growth and productivity. Moreover, we emphasize its possible introduction to smallholder farming systems to provide phytonutrients, and we further highlight research gaps in the existing knowledge regarding MLE application. Generally, MLE is an inexpensive, sustainable, eco-friendly and natural biostimulant that can be used to improve the growth and productivity attributes of various crops under non-stressful and stressful conditions. [ABSTRACT FROM AUTHOR]

(1) Background: the production of onion seeds is limited by the competition between seeds and the vegetative organs and by scape lodging. However, information on the effects of plant growth regulation on onion seed production is scarce. Aim of the present study was to evaluate the seed yield components and germination ability of onion seeds as affected by the timing and dose of an ethylene application, a plant growth regulator able to modulate shoot–flower competition; and chitosan, an elicitor of plant defense mechanisms able to increase its tolerance to various stresses. (2) Methods: Onion was treated with ethylene at the recommended dose (100% RD) of a commercial product, at 150% RD in two contrasting phenological phases or untreated (control), or 'with' or 'without' chitosan, and the seed yield components and germination trend were measured. (3) Results: 100% RD at an early phase of growth did not influence the seed yield and increased the thousand seed weight (TSW) by 3.2%. The application of 150% RD decreased the seed yield by 33.5%, and this occurred irrespective of the timing of application. Such decreases were due to a reduction in the number of seeds per flower. The application of chitosan did not affect the crop at 100% RD and increased the seed yield and slightly increased, but not significantly, the TSW under 150% RD. Germination of the fresh seed was 92%, and 17 months of aging reduced it by 14%, with no effects of the treatments on the germination pattern. (4) Conclusions: the ethylene application mostly affected TSW but not the yield, whereas high doses of ethylene reduced yields irrespective of the timing of application. Such a result may have been due to a delay in the flowering onset that occurred in a relatively dry month. Chitosan sustained its yield when the yield potential was reduced by 150% RD, and such a result was likely due to physical protection from the transpiration since the synthetic fungicides applied did not likely allow the pathogens to infections. These results have implications for establishing the timing and dose of application of plant growth regulators and elicitors in seed onions to sustain the seed quality. [ABSTRACT FROM AUTHOR]

Salicylic acid (SA) is a phenolic phytohormone with critical roles in plant growth regulation and resistance to biotic and abiotic stress. Since low SA concentrations can modulate many plant biochemical responses, innovative analytical tools are required to deeply understand its activity and to control its exogenous application in modern agricultural systems. Herein, a NIR-activated composite based on NaYF4:Yb,Er@NaYF4 core@shell upconversion nanoparticles decorated with the poly(allylamine)-Cu(II) complex [UCNPs-PAAm-Cu(II)] was developed to sensitively determine the SA molecule in plant-derived samples. Accordingly, the PAAm-Cu(II) complex grafted on the UCNPs induces a strategic charge transfer band which triggers a quenching process through a resonance energy transfer (RET) mechanism. Such process is gradually deactivated upon the addition of SA and the consequent formation of the SA-Cu(II) complex, allowing a luminescence recovery in the 1–800 nM linear range. This mechanism is promoted by the strong stability of the SA-Cu(II) complex (log β2-SA/Cu = 19.01) which is over twelve orders of magnitude stronger than the PAAm-Cu2+ counterpart. Furthermore, the equilibrium and kinetic studies on the involved mononuclear Cu2+ complexes formation permitted instantaneous analytical responses and excellent selectivity against other representative phytohormones and metallic cations. The reliability of this method was demonstrated by determining the SA content of some edible fruits and vegetables comprising apple, lemon, kiwi, tomato, and cucumber, whose concentrations ranged from 0.30 to 2.99 μg g−1, with percent recoveries between 94.6 to 102.3%. Thereby, the reported nanocomplex can help to understand the SA activity in plants with significant applications in crop yield improvement and food quality assessment. [ABSTRACT FROM AUTHOR]

Cucumber (Cucumis sativus L.) is an annual climbing herb that belongs to the Cucurbitaceae family and is one of the most important economic crops in the world. The breeding of cucumber varieties with excellent agronomic characteristics has gained more attention in recent years. The size and shape of the leaves or fruit and the plant architecture are important agronomic traits that influence crop management and productivity, thus determining the crop yields and consumer preferences. The growth of the plant is precisely regulated by both environmental stimuli and internal signals. Although significant progress has been made in understanding the plant morphological regulation of Arabidopsis, rice, and maize, our understanding of the control mechanisms of the growth and development of cucumber is still limited. This paper reviews the regulation of phytohormones in plant growth and expounds the latest progress in research regarding the genetic regulation pathways in leaf development, fruit size and shape, branching, and plant type in cucumber, so as to provide a theoretical basis for improving cucumber productivity and cultivation efficiency. [ABSTRACT FROM AUTHOR]

Key message: An alanine to valine mutation of glutamyl-tRNA reductase's 510th amino acid improves 5-aminolevulinic acid synthesis in rice. 5-aminolevulinic acid (ALA) is the common precursor of all tetrapyrroles and plays an important role in plant growth regulation. ALA is synthesized from glutamate, catalyzed by glutamyl-tRNA synthetase (GluRS), glutamyl-tRNA reductase (GluTR), and glutamate-1-semialdehyde aminotransferase (GSAT). In Arabidopsis, ALA synthesis is the rate-limiting step in tetrapyrrole production via GluTR post-translational regulations. In rice, mutations of GluTR and GSAT homologs are known to confer chlorophyll deficiency phenotypes; however, the enzymatic activity of rice GluRS, GluTR, and GSAT and the post-translational regulation of rice GluTR have not been investigated experimentally. We have demonstrated that a suppressor mutation in rice partially reverts the xantha trait. In the present study, we first determine that the suppressor mutation results from a G → A nucleotide substitution of OsGluTR (and an A → V change of its 510th amino acid). Protein homology modeling and molecular docking show that the OsGluTRA510V mutation increases its substrate binding. We then demonstrate that the OsGluTRA510V mutation increases ALA synthesis in Escherichia coli without affecting its interaction with OsFLU. We further explore homologous genes encoding GluTR across 193 plant species and find that the amino acid (A) is 100% conserved at the position, suggesting its critical role in GluTR. Thus, we demonstrate that the gain-of-function OsGluTRA510V mutation underlies suppression of the xantha trait, experimentally proves the enzymatic activity of rice GluRS, GluTR, and GSAT in ALA synthesis, and uncovers conservation of the alanine corresponding to the 510th amino acid of OsGluTR across plant species. [ABSTRACT FROM AUTHOR]

Background: Acyl carrier proteins (ACP) constitute a very conserved carrier protein family. Previous studies have found that ACP not only takes part in the fatty acid synthesis process of almost all organisms, but also participates in the regulation of plant growth, development, and metabolism, and makes plants adaptable to stresses. However, this gene family has not been systematically studied in sorghum. Results: Nine ACP family members were identified in the sorghum genome, which were located on chromosomes 1, 2, 5, 7, 8 and 9, respectively. Evolutionary analysis among different species divided the ACP family into four subfamilies, showing that the SbACPs were more closely related to maize. The prediction results of subcellular localization showed that SbACPs were mainly distributed in chloroplasts and mitochondria, while fluorescence localization showed that SbACPs were mainly localized in chloroplasts in tobacco leaf. The analysis of gene structure revealed a relatively simple genetic structure, that there were 1–3 introns in the sorghum ACP family, and the gene structure within the same subfamily had high similarity. The amplification method of SbACPs was mainly large fragment replication, and SbACPs were more closely related to ACPs in maize and rice. In addition, three-dimensional structure analysis showed that all ACP genes in sorghum contained four α helices, and the second helix structure was more conserved, implying a key role in function. Cis-acting element analysis indicated that the SbACPs might be involved in light response, plant growth and development regulation, biotic and abiotic stress response, plant hormone regulation, and other physiological processes. What's more, qRT-PCR analysis uncovered that some of SbACPs might be involved in the adaptive regulation of drought and salt stresses, indicating the close relationship between fatty acids and the resistance to abiotic stresses in sorghum. Conclusions: In summary, these results showed a comprehensive overview of the SbACPs and provided a theoretical basis for further studies on the biological functions of SbACPs in sorghum growth, development and abiotic stress responses. [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa L.) is a widely grown and important forage crop. However, alkali stress is detrimental to alfalfa yield and nutritional quality. Gamma-aminobutyric acid (GABA) is a signaling molecule, it participates in and responds to metabolic regulation related to plant growth and development and stress. In this study, we clarify the effect of spraying alfalfa seedlings with GABA on the alkali tolerance of the seedlings. We determined that exogenous application of GABA at 75 mmol/L improved the resistance of alfalfa seedlings to alkali stress caused by exposure to 100 mmol/L NaHCO3, pH 8.5. Exogenous GABA significantly increased the chlorophyll content, the accumulation of soluble sugars in the plants, significantly decreased their relative electrical conductivity, malondialdehyde (MDA), superoxide anion (O2−) and hydrogen peroxide (H2O2) contents, and significantly increased the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD). Exogenous GABA increased the activities of GAD and GABA-T, increased the content of glutamate and endogenous GABA, and regulated the expression of the genes MsGAD, MsGABA-T and MsGDH. In alfalfa plants that survived for a long time, compared to the control group, root length and fresh weight were significantly higher. Exogenous GABA had a positive effect on the resistance of alfalfa seedlings to alkali stress, and the effect was closely associated with GAD and GABA-T activity, glutamate content and the levels of endogenous GABA and antioxidants. This work provides a new method for the cultivation of early-stage alfalfa seedlings under low or moderate alkali stress conditions through the application of 75 mmol/L GABA. [ABSTRACT FROM AUTHOR]

An experiment was carried out in a nursery with 220 seedlings of Guadua angustifolia Kunth, by adding silicon (Si) in a commercial fertilizer. Eleven treatments, including the no silicon-control were applied, with concentrations progressively increasing in 600 mg Si up to 6000 mg Si kg-1-dried. We found that, Si was beneficial to the seedling's growth in terms of their stem height, stem base area, leaf area, root length, stem biomass, leaves, roots and total biomass. However, this benefit reached a peak at about 4200 mg Si kg-1, and afterthis concentration the plants did not show any benefit, but instead they stopped absorbing silicon as the inner silicon decreased when the Si in the soil was equal or higher of 2400 mg kg-1. The supplied fertilizer also contained phosphorus (P), but this mineral did not affect the previous variables, nor the absorption of Si. [ABSTRACT FROM AUTHOR]

Jasmonates (JAs) are known for their roles in plant defense and growth regulation. In recent years their roles in nutrient uptake and homeostasis have been explored. Regulation of nutrients uptake is crucial to maintain their optimum level in normal and deficient conditions. Under the deficiency of different nutrients, plants show unique responses like altered root growth, remodeling of root system architecture (RSA), induction of nutrient uptake-related genes, activation of nutrient transporters, and nutrient reallocation. JAs have been shown to regulate these responses in the variable availability of macro-and micronutrients. Emerging evidences revealed that in response to deficiency of macronutrients, such as nitrogen (N), phosphorous (P), and potassium (K+), JA biosynthesis pathway is activated. JA signaling pathway has been implicated in regulating nutrient deficiency-related transcription factors, transporters, and various facets of RSA for optimum plant development. In addition, JA pathway cross-talks with other phytohormones like auxin and ethylene for improving plant growth and adaptive response under nutrient deficiencies. In this review, emerging evidences and the latest developments on involvements of JAs in macro- and micronutrient uptakes, homeostasis, deficiency response, and plant development are discussed. [ABSTRACT FROM AUTHOR]

The study attempts to investigate the presence of structural change in growth of area, production and productivity of selected horticultural crops in India from 1997-98 to 2018-19. The CGR and structural break analysis were employed to examine the growth rates and multiple break periods respectively. The CGR results show that area and production of selected horticultural crops in India grew more during post NHM period than pre NHM period, but there is not a significant growth in productivity of major crops. The structural break analysis shows that shift in growth has been reported after 2005 in selected crops implied that significant growth trend has been observed after NHM implementation. The overall performance in area, production and productivity is quite satisfactory during post-NHM period in major crops except in pepper and tapioca. [ABSTRACT FROM AUTHOR]

An experiment was conducted to evaluate onion varieties for the suitability in Dungarpur, Rajasthan, during 2017-18 and 2018-19. Six high-yielding varieties were tested with five replications in comparison to local variety. Different treatments included onion variety Agrifound Light Red, NHRDF Red, NHRDF Red-2 NHRDF Red-3, NHRDF Red-4 and local variety Udaipur 103. The NHRDF Red-3 produced maximum height of plant (56.46 cm) and number of leaves/plant (17.30). While, NHRDF Red-4 was at par in height of plant (54.24 cm) and number of leaves/plant (17.20). The NHRDF Red recorded minimum (1.04 cm) neck thickness which was at par with Agrifound Light Red (1.11 cm), Udaipur 103 and NHRDF Red-4 (1.16 cm). However, NHRDF Red-3 recorded maximum neck thickness (1.30 cm). The maximum average fresh weight of bulb (98.48 gm) and cured weight of bulb (95.81 gm) were recorded with variety NHRDF Red-3, while NHRDF Red-4 was at par for fresh bulb (92.70 g) and for cured weight of bulbs (89.72 g). The maximum polar diameter of bulb (47.05 mm) and equatorial diameter of bulbs (48.76 mm) were recorded variety NHRDF Red-3, while NHRDF Red-4 was at par for polar diameter of bulbs (44.80 mm) and for equatorial diameter of bulbs (46.56 mm). The NHRDF Red-4 and Agrifound Light Red (153) required minimum days for maturity which was at par with local variety Udaipur 103 (162), while NHRDF Red-2 and NHRDF Red-3 (160) recorded maximum days. [ABSTRACT FROM AUTHOR]

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Legumes coordinate nodulation and plant development to maximize reproductive success, but the underlying molecular mechanisms are not well understood. A recent study by Yun et al. has revealed that nodulation drives root-to-shoot movement of microRNA172 (miR172) to accelerate flowering time, thus building a new bridge between nodulation and plant growth regulation. [ABSTRACT FROM AUTHOR]

The use of biological agents offers a sustainable alternative to chemical control in managing plant diseases. In this study, Bacillus velezensis IFST-221 was isolated from the rhizosphere of a healthy maize plant amidst a population showing severe disease symptoms. The investigation demonstrated a broad-spectrum antagonistic activity of IFST-221 against eight species of pathogenic ascomycetes and oomycetes, suggesting its potential utility in combating plant diseases like maize ear rot and cotton Verticillium wilt. Additionally, our study unveiled that IFST-221 has demonstrated significant plant growth-promoting properties, particularly in maize, cotton, tomato, and broccoli seedlings. This growth promotion was linked to its ability to produce indole-3-acetic acid, nitrogen fixation, phosphate and potassium solubilization, and biofilm formation in laboratory conditions. A complete genome sequencing of IFST-221 yielded a genome size of 3.858 M bp and a GC content of 46.71%. The genome analysis identified 3659 protein-coding genes, among which were nine secondary metabolite clusters with known antimicrobial properties. Additionally, three unknown compounds with potentially novel properties were also predicted from the genomic data. Genome mining also identified several key genes associated with plant growth regulation, colonization, and biofilm formation. These findings provide a compelling case for the application of B. velezensis IFST-221 in agricultural practices. The isolate's combined capabilities of plant growth promotion and antagonistic activity against common plant pathogens suggest its promise as an integrated biological agent in disease management and plant productivity enhancement. • The whole genome of Bacillus velezensis IFST-221 was analyzed, which was obtained from a healthy maize plant in Yunnan province. • IFST-221 demonstrates the capacity to improve the growth of plant seedlings, specifically on the aboveground regions. • IFST-221 also showed potential biocontrol activity against maize ear rot and Verticillium wilt of cotton. [ABSTRACT FROM AUTHOR]

Background: Understanding the adaptive strategies of plants to phosphorus (P) deficiency, particularly the plasticity of structural and physiological responses, is crucial for predicting plant growth. Our study aimed to investigate the growth, root morphological and resistance trait responses of Pinus massoniana seedlings under a fact-based low-P range.A P manipulation experiment (0–9.299 mg·kg−1) was carried out to measure biomass, root morphological and resistance traits of P. massoniana seedlings.The root to shoot biomass ratio changed, however, the belowground biomass did not change in response to decreased P content of the growing substrate. Seedlings extended fine roots (0–2 mm in length) thus increased root surface area to enhance P uptake. The length of coarse root (> 5 mm) and root average diameter increased with P addition. A strong response was found in root resistance traits, which also exhibited higher plasticity and made greater contributions to growth. Antioxidant enzyme activities, malondialdehyde content, acid phosphatase activity, and organic acid content all decreased with P addition, but root vigor showed a more sensitive response, making it a potentially informative indicator for changes in P conditions.Physiological traits related to root resistance were more sensitive and important in plant growth regulation, while root morphological traits showed different adaptative strategies among root classes to regulate biomass and absorptive function. The combined effects of morphological and resistance traits alleviate the limitation of P on plant growth. Our findings will provide insights into the adaptive strategies of plantation growing in subtropical regions under limiting nutrient environment.Methods: Understanding the adaptive strategies of plants to phosphorus (P) deficiency, particularly the plasticity of structural and physiological responses, is crucial for predicting plant growth. Our study aimed to investigate the growth, root morphological and resistance trait responses of Pinus massoniana seedlings under a fact-based low-P range.A P manipulation experiment (0–9.299 mg·kg−1) was carried out to measure biomass, root morphological and resistance traits of P. massoniana seedlings.The root to shoot biomass ratio changed, however, the belowground biomass did not change in response to decreased P content of the growing substrate. Seedlings extended fine roots (0–2 mm in length) thus increased root surface area to enhance P uptake. The length of coarse root (> 5 mm) and root average diameter increased with P addition. A strong response was found in root resistance traits, which also exhibited higher plasticity and made greater contributions to growth. Antioxidant enzyme activities, malondialdehyde content, acid phosphatase activity, and organic acid content all decreased with P addition, but root vigor showed a more sensitive response, making it a potentially informative indicator for changes in P conditions.Physiological traits related to root resistance were more sensitive and important in plant growth regulation, while root morphological traits showed different adaptative strategies among root classes to regulate biomass and absorptive function. The combined effects of morphological and resistance traits alleviate the limitation of P on plant growth. Our findings will provide insights into the adaptive strategies of plantation growing in subtropical regions under limiting nutrient environment.Results: Understanding the adaptive strategies of plants to phosphorus (P) deficiency, particularly the plasticity of structural and physiological responses, is crucial for predicting plant growth. Our study aimed to investigate the growth, root morphological and resistance trait responses of Pinus massoniana seedlings under a fact-based low-P range.A P manipulation experiment (0–9.299 mg·kg−1) was carried out to measure biomass, root morphological and resistance traits of P. massoniana seedlings.The root to shoot biomass ratio changed, however, the belowground biomass did not change in response to decreased P content of the growing substrate. Seedlings extended fine roots (0–2 mm in length) thus increased root surface area to enhance P uptake. The length of coarse root (> 5 mm) and root average diameter increased with P addition. A strong response was found in root resistance traits, which also exhibited higher plasticity and made greater contributions to growth. Antioxidant enzyme activities, malondialdehyde content, acid phosphatase activity, and organic acid content all decreased with P addition, but root vigor showed a more sensitive response, making it a potentially informative indicator for changes in P conditions.Physiological traits related to root resistance were more sensitive and important in plant growth regulation, while root morphological traits showed different adaptative strategies among root classes to regulate biomass and absorptive function. The combined effects of morphological and resistance traits alleviate the limitation of P on plant growth. Our findings will provide insights into the adaptive strategies of plantation growing in subtropical regions under limiting nutrient environment.Conclusion: Understanding the adaptive strategies of plants to phosphorus (P) deficiency, particularly the plasticity of structural and physiological responses, is crucial for predicting plant growth. Our study aimed to investigate the growth, root morphological and resistance trait responses of Pinus massoniana seedlings under a fact-based low-P range.A P manipulation experiment (0–9.299 mg·kg−1) was carried out to measure biomass, root morphological and resistance traits of P. massoniana seedlings.The root to shoot biomass ratio changed, however, the belowground biomass did not change in response to decreased P content of the growing substrate. Seedlings extended fine roots (0–2 mm in length) thus increased root surface area to enhance P uptake. The length of coarse root (> 5 mm) and root average diameter increased with P addition. A strong response was found in root resistance traits, which also exhibited higher plasticity and made greater contributions to growth. Antioxidant enzyme activities, malondialdehyde content, acid phosphatase activity, and organic acid content all decreased with P addition, but root vigor showed a more sensitive response, making it a potentially informative indicator for changes in P conditions.Physiological traits related to root resistance were more sensitive and important in plant growth regulation, while root morphological traits showed different adaptative strategies among root classes to regulate biomass and absorptive function. The combined effects of morphological and resistance traits alleviate the limitation of P on plant growth. Our findings will provide insights into the adaptive strategies of plantation growing in subtropical regions under limiting nutrient environment. [ABSTRACT FROM AUTHOR]

Phosphatidylserine (PS) is an important lipid signaling required for plant growth regulation and salt stress adaptation. However, how PS positively regulate plant salt tolerance is still largely unknown. In this study, IbPSS1 -overexpressed sweetpotato plants that exhibited overproduction of PS was employed to explore the mechanisms underlying the PS stimulation of plant salt tolerance. The results revealed that the IbPSS1 -overexpressed sweetpotato accumulated less Na+ in the stem and leaf tissues compared with the wild type plants. Proteomic profile of roots showed that lignin synthesis-related proteins over-accumulated in IbPSS1 -overexpressed sweetpotato. Correspondingly, the lignin content was enhanced but the influx of Na + into the stele was significantly blocked in IbPSS1 -overexpressed sweetpotato. The results further revealed that ethylene synthesis and signaling related genes were upregulated in IbPSS1 -overexpressed sweetpotato. Ethylene imaging experiment revealed the enhancement of ethylene mainly localized in the root stele. Inhibition of ethylene synthesis completely reversed the PS-overproduction induced lignin synthesis and Na+ influx pattern in stele tissues. Taken together, our findings demonstrate a mechanism by which PS regulates ethylene signaling and lignin synthesis in the root stele, thus helping sweetpotato plants to block the loading of Na+ into the xylem and to minimize the accumulation of Na+ in the shoots. • IbPSS1 -overexpressed sweetpotato exhibited enhanced K+/Na+ homeostasis. • PS enhances lignin synthesis and blocks the Na+ loading into the xylem. • Ethylene signaling is involved in the lignin synthesis and Na+ loading into the xylem. [ABSTRACT FROM AUTHOR]

4-Cl-IAA, and not IAA, stimulates pericarp GA biosynthesis and pericarp growth ([18]), and the expression of ethylene biosynthesis and signalling genes and ethylene response was differentially modified by the two auxins ([6]; [5]). Keywords: Auxin biosynthesis; auxin receptor; 4-chloro-indole-3-acetic acid; ethylene; gibberellin; pea reproductive development; Pisum sativum EN Auxin biosynthesis auxin receptor 4-chloro-indole-3-acetic acid ethylene gibberellin pea reproductive development Pisum sativum 3831 3835 5 06/28/22 20220624 NES 220624 The growth hormone auxin has been implicated as a necessary factor in the development of different types of fruit. Auxins and gibberellins are decreased in deseeded pods, while the addition of auxin can rescue the pericarp growth phenotype, and 4-Cl gives a better response than IAA. The auxins IAA and 4-Cl-IAA differentially modify gibberellin action via ethylene response in developing pea fruit. [Extracted from the article]

Salinity, water scarcity, and nitrogen (N) deficiency are the main limiting factors for plant production. However, over-irrigation and excessive N utilization can also limit the growth and biomass yield of leafy vegetables. The aim of this study is to investigate the growth regulation of spinach (Spinacia oleracea L.) under different levels of irrigation water salinity, water utilization, and nitrogen supply. Combinations of five salinity levels (1, 4, 7, 9, and 11 dS m−1) with three levels of water consumption including deficit irrigation (W–), full irrigation (W0) and over-irrigation (W+), and four levels of N supply (0, 50, 75, and 100% of N requirement) were examined under controlled greenhouse conditions. The least plant biomass, evapotranspiration (ET), and nitrogen use efficiency (NUE) were observed when high-saline water was applied in combination of water and N deficiency. However, the osmotic/drought effect is a short-term effect of salinity that can be further exacerbated by the condition W–. With increasing the fertilizer rate up to 150 mg N kg−1 soil, the plant growth traits increased significantly for all salinity levels; however, an excessive N utilization caused no significant increase. Water stress caused a morphological adaptation in the plant by reducing leaf area and ET, resulting in improved water use efficiency (WUE). With increasing salinity, WUE increased then decreased significantly. In other words, both the relative ET and relative yield were reduced with increasing salinity; however, at intermediate salinity levels (4 and 7 dS m–1), further decline in the former than in the latter resulted in higher WUE values. The stepwise regression analysis showed that the plant yield was affected mostly by WUE, ET, and leaves number (R2 = 0.983***). The findings of this study revealed that the reduced leaf area was the main growth regulation in the spinach plant under stress conditions, which ultimately could enhance WUE. [ABSTRACT FROM AUTHOR]

The phytohormone salicylic acid (SA) not only is a well-known signal molecule mediating plant immunity, but also is involved in plant growth regulation. However, while its role in plant immunity has been well elucidated, its action on plant growth has not been clearly described to date. Recently, increasing evidence has shown that SA plays crucial roles in regulating cell division and cell expansion, the key processes that determines the final stature of plant. This review summarizes the current knowledge on the action and molecular mechanisms through which SA regulates plant growth via multiple pathways. It is here highlighted that SA mediates growth regulation by affecting cell division and expansion. In addition, the interactions of SA with other hormones and their role in plant growth determination were also discussed. Further understanding of the mechanism underlying SA-mediated growth will be instrumental for future crop improvement. [ABSTRACT FROM AUTHOR]

The GRAS (derived from GAI, RGA and SCR) gene family consists of plant‐specific genes, works as a transcriptional regulator and plays a key part in the regulation of plant growth and development. The past decade has witnessed significant progress in understanding and advances on GRAS transcription factors in various plants. A notable concern is to what extent the mechanisms found in plants, particularly crops, are shared by other species, and what other characteristics are dependent on GRAS transcription factor (TFS)‐mediated gene expression. GRAS are involved in many processes that are intimately linked to plant growth regulation. However, GRAS also perform additional roles against environmental stresses, allowing plants to function more efficiently. GRAS increase plant growth and development by improving several physiological processes, such as phytohormone, biosynthetic and signalling pathways. Furthermore, the GRAS gene family plays an important role in response to abiotic stresses, e.g. photooxidative stress. Moreover, evidence shows the involvement of GRAS in arbuscule development during plant–mycorrhiza associations. In this review, the diverse roles of GRAS in plant systems are highlighted that could be useful in enhancing crop productivity through genetic modification, especially of crops. This is the first review to report the role and function of the GRAS gene family in plant systems. Furthermore, a large number of studies are reviewed, and several limitations and research gaps identified that must be addressed in future studies. [ABSTRACT FROM AUTHOR]

Brassinosteroid emerges as an essential phytohormone that helps the plant to maintain plant growth and development. It also helps the plants grow well under adverse conditions along with normal conditions. In this review article, we have discussed the functional role of brassinosteroid (BRS) in plants under salinity stress conditions. Salinity stress is one of the most devastating abiotic stresses which adversely affect plant growth by disturbing their metabolic pathway. This article also comprises the occurrence, structure and signalling pathway of the brassinosteroid. Application of brassinosteroid improves the plant status under salinity by enhancing the antioxidant enzyme activity in plants. Moreover, we also reported the different growth parameters enhanced by brassinosteroid application in plants under salinity. BRSs also maintain plant growth through the regulation of expression of various genes whose products are involved in various biochemical and physiological processes. This review is based on the various aspects in much detail which are required to understand the proper mechanism of BRS, such as i) the role of BRS signaling pathways in providing tolerance to the plants, ii) changes due to the presence or absence of BRS in plants under stress conditions, iii) BRSs application on the regulation of different genes and transcriptional factor, iv) regulation in ion homeostasis, v) reduction of oxidative stress via different mechanisms under salinity stress. However, a lot of knowledge is required to understand the role of BRS in alleviating salinity stress and needs future research work on BRS with its different derivatives in the alleviation of salt stress. [ABSTRACT FROM AUTHOR]

Vapor pressure deficit (VPD) has been identified as an increasingly important driver of plant functioning, and thus VPD regulation has been widely recognized as having the potential to improve plant growth and productivity. We monitored the trend of the VPD and observed the effect of VPD regulation by irrigating the water using VPD control equipment that automatically inserts fogging water when the VPD exceeds 1.2 kPa. Tomato crops were planted in soil, coconut fiber, and soil above poly vinyl chloride trays to observe the effectiveness of VPD regulation and the planting environment. As a result, there was no significant difference in the effect of VPD regulation on the overall growth stages of tomato crops whether they grew in soil, trays with soil, or trays with coconut fiber. However, in the case of crops grown in a tray with coconut fiber, the initial growth was similar, but the total yield and total commercial yield showed approximately 89% and 88% improvement, respectively. The number of total fruits was also improved by 49% on average. [ABSTRACT FROM AUTHOR]

The phytohormone salicylic acid (SA) not only is a well-known signal molecule mediating plant immunity, but also is involved in plant growth regulation. However, while its role in plant immunity has been well elucidated, its action on plant growth has not been clearly described to date. Recently, increasing evidence has shown that SA plays crucial roles in regulating cell division and cell expansion, the key processes that determines the final stature of plant. This review summarizes the current knowledge on the action and molecular mechanisms through which SA regulates plant growth via multiple pathways. It is here highlighted that SA mediates growth regulation by affecting cell division and expansion. In addition, the interactions of SA with other hormones and their role in plant growth determination were also discussed. Further understanding of the mechanism underlying SA-mediated growth will be instrumental for future crop improvement.

Background: Zinc finger homeodomain (ZHD) protein is a plant-specific transcription factor and a potential regulator of phosphoenolpyruvate carboxylase (PEPCase)-coding genes, and it also participates in plant growth regulation and abiotic stress responses. To study the function of MsZF-HD genes in the alkaline stress response, this paper assessed biological information and performed transcriptome analysis of the MsZF-HD gene family by using the genomes of two different varieties of alfalfa (XinJiangDa Ye and Zhongmu No. 1). Results: In total, 49 and 11 MsZF-HD genes were identified in the two different varieties respectively, including the alleles of XinJiangDa Ye. According to their phylogenetic relationships, the 60 MsZF-HD genes were divided into 5 ZHD subfamilies and 1 MIF subfamily. A total of 88.3% of MsZF-HD genes do not contain introns and are unevenly distributed among the 6 chromosomes of alfalfa. A collinearity analysis indicated that 26 genes of XinJiangDa Ye have no orthologous genes in Zhongmu No. 1, although these genes (such as ZHD-X1–2, ZHD-X3–2 and ZHD-X4–2) have homologous genes in Arabidopsis thaliana, Medicago truncatula and Glycine max. Through RNA-seq and qRT–PCR verification, it was found that MsZF-HD genes are downregulated to participate in the alkaline stress response. Conclusion: The results of this study may lay the foundation for the cloning and functional study of MsZF-HD genes and provide a theoretical basis for revealing the difference between XinJiangDa Ye and Zhongmu No. 1 at the genome level. [ABSTRACT FROM AUTHOR]

In the course of our research on the structure--activity relationship of 5,6-dihydro-2 H -pyran-2-one, (S)-6-[(R)-2-hydroxy-6-(4-fluorophenyl ) hexyl]-5,6-dihydro-2 H -pyran-2-one was found to show 2-3-fold more potent plant growth inhibitory activity against Italian ryegrass shoots ( IC50 = 95 μm ) and roots ( IC50 = 17 μm ) than compound bearing unsubstituted phenyl group. The small and electron withdrawing atom at 4-position of the benzene ring caused the higher activity. [ABSTRACT FROM AUTHOR]

Auxin, one of the first identified and most widely studied phytohormones, has been and will remain a hot topic in plant biology. After more than a century of passionate exploration, the mysteries of its synthesis, transport, signaling, and metabolism have largely been unlocked. Due to the rapid development of new technologies, new methods, and new genetic materials, the study of auxin has entered the fast lane over the past 30 years. Here, we highlight advances in understanding auxin signaling, including auxin perception, rapid auxin responses, TRANSPORT INHIBITOR RESPONSE 1 and AUXIN SIGNALING F‐boxes (TIR1/AFBs)‐mediated transcriptional and non‐transcriptional branches, and the epigenetic regulation of auxin signaling. We also focus on feedback inhibition mechanisms that prevent the over‐amplification of auxin signals. In addition, we cover the TRANSMEMBRANE KINASE‐mediated non‐canonical signaling, which converges with TIR1/AFBs‐mediated transcriptional regulation to coordinate plant growth and development. The identification of additional auxin signaling components and their regulation will continue to open new avenues of research in this field, leading to an increasingly deeper, more comprehensive understanding of how auxin signals are interpreted at the cellular level to regulate plant growth and development. [ABSTRACT FROM AUTHOR]

Potassium (K) is an essential element for the growth and development of plants; however, its scarcity or excessive level leads to distortion of numerous functions in plants. It takes part in the control of various significant functions in plant advancement. Because of the importance index, K is regarded second after nitrogen for whole plant growth. Approximately, higher than 60 enzymes are reliant on K for activation within the plant system, in which K plays a vital function as a regulator. Potassium provides assistance in plants against abiotic stress conditions in the environment. With this background, the present paper reviews the physiological functions of K in plants like stomatal regulation, photosynthesis and water uptake. The article also focuses upon the uptake and transport mechanisms of K along with its role in detoxification of reactive oxygen species and in conferring tolerance to plants against abiotic stresses. It also highlights the research progress made in the direction of K mediated signaling cascades. • Potassium has diverse role in plant growth and development. • Potassium is responsible for activation of several vital plant enzymes. • Potassium regulate water balance in plants and protect plants from abiotic stress-induced damages. • Potassium plays a vital role in mitigating oxidative stress in plants. [ABSTRACT FROM AUTHOR]

Melatonin is an evolutionarily conserved multifunctional molecule that is widely found in different parts of plants. In addition to its role in regulating plant growth and development, melatonin plays an important role in improving plant biotic and abiotic stress tolerance, which is an important molecule for protecting plants from abiotic and biotic stresses. The role of melatonin in plant growth and development is manifested in the regulation of seed germination, root development, fruit maturation, and senescence. Melatonin primarily improves plant stress resistance by improving plant antioxidant efficiency, reducing the inhibition of photosynthesis, and changing the expression of stress resistance-related genes. This paper reviews the regulation of melatonin on plant growth and development and the molecular mechanisms by which melatonin improves plant tolerance to abiotic and biogenic stresses and analyzes the relationship between melatonin and other signaling molecules and signaling pathways. The future research direction of plant melatonin is prospected. [ABSTRACT FROM AUTHOR]

SUMMARY: Drought stress constitutes one of the major constraints to agriculture all over the world, and its devastating effect is only expected to increase in the following years due to climate change. Concurrently, the increasing food demand in a steadily growing population requires a proportional increase in yield and crop production. In the past, research aimed to increase plant resilience to severe drought stress. However, this often resulted in stunted growth and reduced yield under favorable conditions or moderate drought. Nowadays, drought tolerance research aims to maintain plant growth and yield under drought conditions. Overall, recently deployed strategies to engineer drought tolerance in the lab can be classified into a 'growth‐centered' strategy, which focuses on keeping growth unaffected by the drought stress, and a 'drought resilience without growth penalty' strategy, in which the main aim is still to boost drought resilience, while limiting the side effects on plant growth. In this review, we put the scope on these two strategies and some molecular players that were successfully engineered to generate drought‐tolerant plants: abscisic acid, brassinosteroids, cytokinins, ethylene, ROS scavenging genes, strigolactones, and aquaporins. We discuss how these pathways participate in growth and stress response regulation under drought. Finally, we present an overview of the current insights and future perspectives in the development of new strategies to improve drought tolerance in the field. Significance Statement: In this review, several molecular pathways that participate in plant growth regulation under drought stress are discussed. An overview of successful strategies and potential candidates to enhance plant growth under drought is presented. [ABSTRACT FROM AUTHOR]

Summary: The molecular mechanisms of quantitative resistance (QR) to fungal pathogens and their relationships with growth pathways are poorly understood.We identified tomato TRK1 (TPK1b Related Kinase1) and determined its functions in tomato QR and plant growth. TRK1 is a receptor‐like cytoplasmic kinase that complexes with tomato LysM Receptor Kinase (SlLYK1). SlLYK1 and TRK1 are required for chitin‐induced fungal resistance, accumulation of reactive oxygen species, and expression of immune response genes. Notably, TRK1 and SlLYK1 regulate SlMYC2, a major transcriptional regulator of jasmonic acid (JA) responses and fungal resistance, at transcriptional and post‐transcriptional levels.Further, TRK1 is also required for maintenance of proper meristem growth, as revealed by the ectopic meristematic activity, enhanced branching, and altered floral structures in TRK1 RNAi plants. Consistently, TRK1 interacts with SlCLV1 and SlWUS, and TRK1 RNAi plants show increased expression of SlCLV3 and SlWUS in shoot apices. Interestingly, TRK1 suppresses chitin‐induced gene expression in meristems but promotes expression of the same genes in leaves. SlCLV1 and TRK1 perform contrasting functions in defense but similar functions in plant growth.Overall, through molecular and biochemical interactions with critical regulators, TRK1 links upstream defense and growth signals to downstream factor in fungal resistance and growth homeostasis response regulators. [ABSTRACT FROM AUTHOR]

Late embryogenesis abundant (LEA) proteins are important for promoting the growth and stress tolerance of plants. They are widely involved in plant growth regulation and responses to hormones and environmental factors. However, knowledge of the functions of the LEA gene in ginseng species remains limited. In this study, a Panax ginseng LEA gene (PgLEA) expression vector was constructed, and stable transgenic Arabidopsis lines were established. The PgLEA protein was classified in the LEA-2 subgroup. Reverse-transcription quantitative PCR analysis showed that the expression of PgLEA increased under 300 mM NaCl or 10 % (m/v) polyethylene glycol treatments. Under salt and osmotic stresses, overexpression of PgLEA in transgenic Arabidopsis plants improved germination rate, root length, and survival rate compared to wild-type plants. In response to drought or salt stress, transgenic plants increased proline accumulation, decreased malonaldehyde content and ion leakage. Furthermore, the transgenic plants exhibited significantly increased activity of superoxide dismutase, peroxidase, and catalase, and reduced accumulation of hydrogen peroxide and superoxide. Moreover, overexpression of PgLEA affected the expression of genes related to salt/drought stress. Taken together, PgLEA is a positive regulator of drought and salinity stress, and positively functioned in pleiotropic effects through regulating osmotic balance, reactive oxygen species scavenging and inducing transcription of stress-related genes. PgLEA may enable ginseng plants to adapt to adverse environments. The data presented herein imply that PgLEA may be useful for breeding new stress-tolerant ginseng cultivars. [ABSTRACT FROM AUTHOR]

Background: Compared with other abiotic stresses, drought stress causes serious crop yield reductions. Poly-γ-glutamic acid (γ-PGA), as an environmentally friendly biomacromolecule, plays an important role in plant growth and regulation. Results: In this project, the effect of exogenous application of γ-PGA on drought tolerance of maize (Zea mays. L) and its mechanism were studied. Drought dramatically inhibited the growth and development of maize, but the exogenous application of γ-PGA significantly increased the dry weight of maize, the contents of ABA, soluble sugar, proline, and chlorophyll, and the photosynthetic rate under severe drought stress. RNA-seq data showed that γ-PGA may enhance drought resistance in maize by affecting the expression of ABA biosynthesis, signal transduction, and photosynthesis-related genes and other stress-responsive genes, which was also confirmed by RT–PCR and promoter motif analysis. In addition, diversity and structure analysis of the rhizosphere soil bacterial community demonstrated that γ-PGA enriched plant growth promoting bacteria such as Actinobacteria, Chloroflexi, Firmicutes, Alphaproteobacteria and Deltaproteobacteria. Moreover, γ-PGA significantly improved root development, urease activity and the ABA contents of maize rhizospheric soil under drought stress. This study emphasized the possibility of using γ-PGA to improve crop drought resistance and the soil environment under drought conditions and revealed its preliminary mechanism. Conclusions: Exogenous application of poly-γ-glutamic acid could significantly enhance the drought resistance of maize by improving photosynthesis, and root development and affecting the rhizosphere microbial community. [ABSTRACT FROM AUTHOR]