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Plant hormones are a group of small signaling molecules produced by plants at very low concentrations that have the ability to move and function at distal sites. Hormone homeostasis is critical to balance plant growth and development and is regulated at multiple levels, including hormone biosynthesis, catabolism, perception, and transduction. In addition, plants move hormones over short and long distances to regulate various developmental processes and responses to environmental factors. Transporters coordinate these movements, resulting in hormone maxima, gradients, and cellular and subcellular sinks. Here, we summarize the current knowledge of most of the characterized plant hormone transporters with respect to biochemical, physiological, and developmental activities. We further discuss the subcellular localizations of transporters, their substrate specificities, and the need for multiple transporters for the same hormone in the context of plant growth and development.

Optimal plant development requires root uptake of 14 essential mineral elements from the soil. Since the bioavailability of these nutrients underlies large variation in space and time, plants must dynamically adjust their root architecture to optimize nutrient access and acquisition. The information on external nutrient availability and whole-plant demand is translated into cellular signals that often involve phytohormones as intermediates to trigger a systemic or locally restricted developmental response. Timing and extent of such local root responses depend on the overall nutritional status of the plant that is transmitted from shoots to roots in the form of phytohormones or other systemic long-distance signals. The integration of these systemic and local signals then determines cell division or elongation rates in primary and lateral roots, the initiation, emergence, or elongation of lateral roots, as well as the formation of root hairs. Here, we review the cascades of nutrient-related sensing and signaling events that involve hormones and highlight nutrient-hormone relations that coordinate root developmental plasticity in plants., (Copyright © 2021 The Author. Published by Elsevier Inc. All rights reserved.)

Plants retain the ability to produce new organs throughout their life cycles. Continuous aboveground organogenesis is achieved by meristems, which are mainly organized, established, and maintained in the shoot apex and leaf axils. This paper will focus on reviewing the recent progress in understanding the regulation of shoot apical meristem and axillary meristem development. We discuss the genetics of plant meristems, the role of plant hormones and environmental factors in meristem development, and the impact of epigenetic factors on meristem organization and function.

Plant development is different from animals by many fundamental aspects; as they have immobilized cells, a rigid cell wall, and the large central vacuole. Plant growth and cell division are restricted to the specific area of the shoot and root called meristems. Plants have the ability to carry out differentiation, dedifferentiation and redifferentiation. In plants, the growth and differentiation processes are controlled by hormonal and genetic factors. Phytohormones can exert independent/ dependent actions on plant growth and development. A pool of stem cells is placed at the niche of the apex meristem, which is the source of self-renewal of the cell system and its maintenance to provide cells to differentiated tissues. A complex interaction network between hormones and other factors maintains a balance between cell division and differentiation. Auxins promote the growth, gibberellins' function in seed germination, cytokinin's influence on cell division and delay leaf senescence; abscisic acid promotes the stomatal closure and bud dormancy, while salicylic acid promotes resistance against different diseases. Plants are often exposed to different abiotic and biotic stresses, for example, heat, cold, drought, salinity etc., whereas biotic stress arises mainly from fungi, bacteria, insect, etc. Phytohormones play a critical role in well-developed mechanisms that help to perceive the stress signal and enable the plant's optimal growth response. In this review, we studied both the intrinsic and extrinsic factors which govern growth and differentiation of plants under normal and stress condition. This review also deals with genetic modifications occurring in the cell and cell signaling during growth and differentiation., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: The presence of a polar auxin transport stream has long been correlated with the differentiation and patterning of vascular cells across vascular plants. As our understanding of auxin transport and vascular development has grown, so too has evidence for the correlation between these processes. However, a clear understanding of the cellular and molecular mechanisms driving this correlation has not been elucidated., Scope: This article examines the hypothesis that canalization via polar auxin transport regulates vascular reconnection and patterning in the stem after wounding or grafting. We examine the evidence for the causal nature of the relationship and the suggested role that other hormones may play. Data are presented indicating that in grafted plants the degree of auxin transport may not always correlate with vascular reconnection. Furthermore, data on grafting success using plants with a range of hormone-related mutations indicate that these hormones may not be critical for vascular reconnection., Conclusions: In the past, excellent work examining elements of auxin synthesis, transport and response in relation to vascular development has been carried out. However, new experimental approaches are required to test more directly the hypothesis that auxin transport regulates stem vascular reconnection after wounding or grafting. This could include studies on the timing of the re-establishment of auxin transport and vascular reconnection after grafting and the influence of auxin transport mutants and inhibitors on these processes using live imaging., (© The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Phytohormones are natural chemical messengers that play critical roles in the regulation of plant growth and development as well as responses to biotic and abiotic stress factors, maintaining plant homeostasis, and allowing adaptation to environmental changes. The discovery of a new class of phytohormones, the brassinosteroids (BRs), almost 40 years ago opened a new era for the studies of plant growth and development and introduced new perspectives in the regulation of agronomic traits through their use in agriculture. BRs are a group of hormones with significant growth regulatory activity that act independently and in conjunction with other phytohormones to control different BR-regulated activities. Genetic and molecular research has increased our understanding of how BRs and their cross-talk with other phytohormones control several physiological and developmental processes. The present article provides an overview of BRs' discovery as well as recent findings on their interactions with other phytohormones at the transcriptional and post-transcriptional levels, in addition to clarifying how their network works to modulate plant growth, development, and responses to biotic and abiotic stresses.

Mitophagy is a conserved cellular process that is important for autophagic removal of damaged mitochondria to maintain a healthy mitochondrial population. Mitophagy also appears to occur in plants and has roles in development, stress response, senescence, and programmed cell death. However, many of the genes that control mitophagy in yeast and animal cells are absent from plants, and no plant proteins marking defunct mitochondria for autophagic degradation are yet known. New insights implicate general autophagy-related proteins in mitophagy, affecting the senescence of plant tissues. Mitophagy control and its importance for energy metabolism, survival, signaling, and cell death in plants are discussed. Furthermore, we suggest mitochondrial membrane proteins containing ATG8-interacting motifs, which might serve as mitophagy receptor proteins in plant mitochondria., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The phytohormone cytokinin plays diverse roles in plant development, influencing many agriculturally important processes, including growth, nutrient responses and the response to biotic and abiotic stresses. Cytokinin levels in plants are regulated by biosynthesis and inactivation pathways. Cytokinins are perceived by membrane-localized histidine-kinase receptors and are transduced through a His-Asp phosphorelay to activate a family of transcription factors in the nucleus. Here, and in the accompanying poster, we summarize the current understanding of cytokinin metabolism, transport and signaling, and discuss how this phytohormone regulates changes in gene expression to mediate its pleiotropic effects., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2018. Published by The Company of Biologists Ltd.)

The development of plant leaves follows a common basic program that is flexible and is adjusted according to species, developmental stage and environmental circumstances. Leaves initiate from the flanks of the shoot apical meristem and develop into flat structures of variable sizes and forms. This process is regulated by plant hormones, transcriptional regulators and mechanical properties of the tissue. Here, we review recent advances in the understanding of how these factors modulate leaf development to yield a substantial diversity of leaf forms. We discuss these issues in the context of leaf initiation, the balance between morphogenesis and differentiation, and patterning of the leaf margin., (© 2014. Published by The Company of Biologists Ltd.)

Leaf senescence is a very important trait that limits yield and biomass accumulation of agronomic crops and reduces post-harvest performance and the nutritional value of horticultural crops. Significant advance in physiological and molecular understanding of leaf senescence has made it possible to devise ways of manipulating leaf senescence for agricultural improvement. There are three major strategies in this regard: (i) plant hormone biology-based leaf senescence manipulation technology, the senescence-specific gene promoter-directed IPT system in particular; (ii) leaf senescence-specific transcription factor biology-based technology; and (iii) translation initiation factor biology-based technology. Among the first strategy, the P SAG12 -IPT autoregulatory senescence inhibition system has been widely explored and successfully used in a variety of plant species for manipulating senescence. The vast majority of the related research articles (more than 2000) showed that crops harbouring the autoregulatory system displayed a significant delay in leaf senescence without any abnormalities in growth and development, a marked increase in grain yield and biomass, dramatic improvement in horticultural performance, and/or enhanced tolerance to drought stress. This technology is approaching commercialization. The transcription factor biology-based and translation initiation factor biology-based technologies have also been shown to be very promising and have great potentials for manipulating leaf senescence in crops. Finally, it is speculated that technologies based on the molecular understanding of nutrient recycling during leaf senescence are highly desirable and are expected to be developed in future translational leaf senescence research., (© The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Peptide hormones regulate plant development, growth, and stress responses. Sulfated peptides represent a class of proteins that undergo posttranslational modification by tyrosylprotein sulfotransferase (TPST), followed by specific enzymatic cleavage to generate mature peptides. This process contributes to the formation of various bioactive peptides, including PSKs (PHYTOSULFOKINEs), PSYs (PLANT PEPTIDE CONTAINING SULFATED TYROSINE), CIFs (CASPARIAN STRIP INTEGRITY FACTOR), and RGFs (ROOT MERISTEM GROWTH FACTOR). In the past three decades, significant progress has been made in understanding the molecular mechanisms of sulfated peptides that regulate plant development, growth, and stress responses. In this review, we explore the sequence properties of precursors, posttranslational modifications, peptide receptors, and signal transduction pathways of the sulfated peptides, analyzing their functions in plants. The cross-talk between PSK/RGF peptides and other phytohormones, such as brassinosteroids, auxin, salicylic acid, abscisic acid, gibberellins, ethylene, and jasmonic acid, is also described. The significance of sulfated peptides in crops and their potential application for enhancing crop productivity are discussed, along with future research directions in the study of sulfated peptides. [ABSTRACT FROM AUTHOR]

Graft healing involves a series of cytological and molecular events including wound responses, callus formation and vascular bundle remodelling. Hormones are important signalling molecules regulating plant development and responses to environmental stimuli. However, the detailed dynamics of phytohormones in graft healing remain elusive. In this research, internodes above and below the graft site were harvested from 0 to 168 h after grafting (HAG), and liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to determinate jasmonic acid, auxin, cytokinin, ethylene, salicylic acid, abscisic acid and gibberellin levels during the graft healing process. Uniform manifold approximation and projection (UMAP) and k-means analyses were performed to explore hormone spatio-temporal dynamics. We found the stage-specific and asymmetric accumulation of phytohormones in the tomato graft healing process. At the early healing stage (before vascular bundle reconnection), IAA, cZ, ABA, JA and SA mainly accumulated above the graft site, while tZ and ACC mainly accumulated below the graft site. MEIAA, ICAld and IP mainly accumulated at the later stage. Comminated with the healing process, we suggested that JA is mainly involved in wound responses, IAA is beneficial to the formation of callus and vascular cell development, tZ promotes cell division, and IP is linked to vascular bundle remodelling. In addition, expression of JA-related genes SlMYC2 and SlJAZ2, IAA-related gene SlIAA1, tZ-related genes SlHP2 and SlRR8, and IP-related gene SlRR9 correlated with hormone accumulation. The findings provide important information about the hormones and genes involved in the tomato graft healing process. [ABSTRACT FROM AUTHOR]

ABSTRACT Plant growth and development are governed via signal networks that connect inputs from nutrient status, hormone signals, and environmental cues. Substantial researches have indicated a pivotal role of sugars as signalling molecules in plants that integrate external environmental cues and other nutrients with intrinsic developmental programmes regulated via multiple plant hormones. Therefore, plant growth and development are controlled through complication signalling networks. However, in many studies, to obtain more obviously experimental findings, excess concentrations of applied exogenous sugars have aggravated the complexity of this signalling networks. Once researchers underestimate this complexity, a series of contradictory or contrasting findings will be generated. More importantly, in terms of these contradictory findings, more contradictory study outcomings are derived. In this review, we carefully analyze some reports, and find that these reports have confused or neglected that the sugar‐antagonism of ethylene signalling is specific or conditional. As a result, many contradictory conclusions are generated, which will in turn misdirect the scientific community. [ABSTRACT FROM AUTHOR]

Sprouts, as an edible vegetable with rich nutrients and health care efficacy, have been increasingly favored by people in recent years. Plant hormones are intrinsic mediators of plant growth and development. The impacts of plant hormone treatment on the growth and quality of sprouts were summarized, and the potential mechanisms were briefly discussed. Moreover, this review explored prospective applications and investigations to promote the sprouts industry. Proper plant hormone treatment could promote the seed germination rate, hypocotyl growth, and fresh weight of sprouts. Meantime, appropriate plant hormone treatment could enhance the bioactive compound contents (such as total phenolic, pigments, and vitamins), antioxidant capacity, and anti-adipogenic and anti-diabetic activities of sprouts. Furthermore, hormones could delay the discoloration progress and promote the antioxidant capacity in sprouts, thus maintaining the postharvest quality. Although the impact of hormones on sprout quality is mainly dependent on the kind, dose, and treatment method of the hormone, the sprout species and cultivars, the growth phase, environmental factors, and others, plant hormone treatment is still a practical and prospective strategy in sprout industry to produce sprouts with enhanced growth and quality. [ABSTRACT FROM AUTHOR]

Phytohormones promote growth in the vegetative phase, flowering and fruit development. A novel class of PGR comprises brassinosteroids (BRs) and polyamines (PAs). In fruit crops, fruit drop at the maturity stage is controlled by the external application of BRs and PAs. BRs such as brassinolide, 24-epibrassinolide and 28-homobrassinolide and PAs such as putrescine, spermidine and spermine play significant roles in plant growth and development. Brassinolide provides tolerance against biotic and abiotic stresses. 24-Epibrassinolide promotes blossoming, fruit retention, fruit set and fruit growth. 28-homobrassinolide promotes cell division and cell elongation. Putrescine enhances seed germination and adventitious root formation in seedlings. Moreover, spermidine provides tolerance against drought and salinity. Furthermore, spermine promotes flowering and fruiting and competes with ethylene precursors. It would be beneficial to apply plant growth regulators such as BRs and PAs to increase fruit yield and quality. This review discusses how phytohormone (BR and PA) application can improve the productivity, quality, physiological, biochemical and postharvest aspects of some tropical, subtropical and temperate fruits and focuses on research areas such as the mode of action and stage of application of BRs and PAs which enhance the yield and quality of these perishable fruit crops. Article highlights: The newly emerged plant growth hormones brassinosteroids and polyamines are vital PGRs for the cultivation of horticulture commodities. BRs and PAs are environmentally safe phytohormones that improve the yield and quality of fruits. These materials are effectively utilized in both fruit production and postharvest management. [ABSTRACT FROM AUTHOR]

Seed germination is a pivotal stage in the plant life cycle, orchestrated by a myriad of internal and external factors, notably plant hormones. The underlying molecular mechanisms governing rice seed germination remain largely unelucidated. Herein, we uncover OsMBF1a as a crucial regulatory factor that employs a dual strategy to promote seed germination: positively activating genes involved in gibberellin (GA) biosynthesis pathways, while negatively regulating key genes responsible for abscisic acid (ABA) synthesis. Furthermore, OsMBF1a modulates the endogenous levels of ABA and GA in rice seeds, reinforcing its central role in the germination process. The expression of ZmMBF1a and ZmMBF1b, the homologous genes in maize, in rice seeds similarly affects germination, indicating the conserved functionality of MBF1 family genes in regulating seed germination. This study provides novel insights into the molecular mechanisms underlying rice seed germination and underscores the significance of MBF1 family genes in plant growth and development. [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]

Background: Seed hypocotyl germination signifies the initiation of the life cycle for plants and represents a critical stage that heavily influences subsequent plant growth and development. While previous studies have established the melatonin (MEL; N-acetyl-5-methoxytrytamine) effect to stimulate seed germination of some plants, its specific role in peony germination and underlying physiological mechanism have yet to be determined. This study aims to evaluate the MEL effect for the hypocotyl germination of peony seeds, further ascertain its physiological regulation factors. Methods: In this work, seeds of Paeonia ostia 'Fengdan' were soaked into MEL solution at concentrations of 50, 100, 200, and 400 µM for 48 h and then germinated in darkness in incubators. Seeds immersed in distilled water without MEL for the same time were served as the control group. Results: At concentrations of 100 and 200 µM, MEL treatments improved the rooting rate of peony seeds, while 400 µM inhibited the process. During seed germination, the 100 and 200 µM MEL treatments significantly reduced the starch concentration, and α-amylase was the primary amylase involved in the action of melatonin. Additionally, compared to the control group, 100 µM MEL treatment significantly increased the GA3 concentration and radicle thickness of seeds, but decreased ABA concentration. The promotion effect of 200 µM MEL pretreatment on GA1 and GA7 was the most pronounced, while GA4 concentration was most significantly impacted by 50 µM and 100 µM MEL. Conclusion: Correlation analysis established that 100 µM MEL pretreatment most effectively improved the rooting rate characterized by increasing α-amylase activity to facilitate starch decomposition, boosting GA3 levels, inhibiting ABA production to increase the relative ratio of GA3 to ABA. Moreover, MEL increased radicle thickness of peony seeds correlating with promoting starch decomposition and enhancing the synthesis of GA1 and GA7. [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]

The endogenous levels of plant hormones, including gibberellins (GAs), are strictly regulated and maintained during growth and development in seed plants. The regulation of endogenous levels of bioactive GAs is mediated by the mechanisms of their biosynthesis and inactivation. The moss Physcomitrium patens harbors a partial GA biosynthetic pathway from geranylgeranyl diphosphate to ent-kaurenoic acid (KA). Recently, we have identified ent-3β-hydroxy kaurenoic acid (3OH-KA) as a biologically active metabolite of KA to control the protonemal cell differentiation. In addition, ent-2α-hydroxy kaurenoic acid catalyzed by KA 2-oxidase (KA2ox) was also identified as inactive product. Although the activation and inactivation pathways from KA have been identified, the inactivation pathway of 3OH-KA remains to be elucidated. Considering the GA inactivation mechanism of flowering plants, in which GA2ox hydroxylates the C-2 position of GAs as part of the biosynthetic pathway, it was presumed that 3OH-KA was converted to 2,3-dihydroxy KA by PpKA2ox; however, this work shows that PpKA2ox undergoes hydroxylation at the C-16 position to synthesize a new compound ent-3β,16β-dihydroxy kaurenoic acid (3,16diOH-KA) from 3OH-KA. The protonemal cell differentiation activity of 3,16diOH-KA was low, and 3,16diOH-KA was detected in wild-type strains. These results indicate that 3,16diOH-KA was the major inactivating metabolite of 3OH-KA. [ABSTRACT FROM AUTHOR]

Plants can experience a variety of environmental stresses that significantly impact their fitness and survival. Additionally, biotic stress can harm agriculture, leading to reduced crop yields and economic losses worldwide. As a result, plants have developed defense strategies to combat potential invaders. These strategies involve regulating redox homeostasis. Several studies have documented the positive role of plant antioxidants, including Ascorbate (Asc), under biotic stress conditions. Asc is a multifaceted antioxidant that scavenges ROS, acts as a co‐factor for different enzymes, regulates gene expression, and facilitates iron transport. However, little attention has been given to Asc and its transport, regulatory effects, interplay with phytohormones, and involvement in defense processes under biotic stress. Asc interacts with other components of the redox system and phytohormones to activate various defense responses that reduce the growth of plant pathogens and promote plant growth and development under biotic stress conditions. Scientific reports indicate that Asc can significantly contribute to plant resistance against biotic stress through mutual interactions with components of the redox and hormonal systems. This review focuses on the role of Asc in enhancing plant resistance against pathogens. Further research is necessary to gain a more comprehensive understanding of the molecular and cellular regulatory processes involved. [ABSTRACT FROM AUTHOR]

In aquatic ecological restoration projects, V. natans (Vallisneria natans (Lour.) Hara), a species of submergent plant, after being transplanted often experiences a poor growing condition and a lengthy adaption period, however, brassinolides possess considerable effectiveness of plant development and metabolism according to available research reports. In an attempt to employ a phytohormone soaking pre-treatment method to study the effect of brassinolides' effect on V. natans development, a laboratory experiment was conducted probing into the influencing factors: brassinolides dosage (0, 0.25, 0.5, 1, 2 and 4 mg/L) and soaking time (10, 20, and 40 minutes). The results showed that the pre-treatment with brassinolide facilitated the improvement to some extent of biomass, plant height, number of leaves, number of tillers, and chlorophyll of V. natans, and that the effect of soaking solution concentration was more pronounced than immersion time; it appeared that under the condition of above three soaking intervals the biomass of V. natans increased to the maximum at the solution concentration of 0.5 mg/L; however, 10 min soaking time gave rise to biggst boosting effect, and from the perspective of plant height indicator, as the soaking time was 10 min brassinolide of 0.25-2 mg/L concentration had a notable positive effect on the plant height of V. natans (P<0.05). In terms of chlorophyll indicators, it was the best condition that the content of chlorophyll a and chlorophyll b of V. natans was boosted when brassinolide concentration ranged 0.5-1 mg/L and soaking time was 10 min. In accordance with the experimental data obtained and considering economic cost and time cost, it is recommended that prior to the transplantation V. natans be soaked with brassinolide at a concentration of 0.5 mg/L for 10 min, in this way the problem of V. natans colonizationcan could be successfully solved. Finally, it is expected that the experimental results could provide theoretical references for the quick recovery of submerged macrophytes in aquatic environment. [ABSTRACT FROM AUTHOR]

Background: Small-secreted peptides are increasingly recognized as a novel class of intracellular signal molecules, playing crucial roles in plant growth and development. However, the precise role and mechanism governed by peptides containing Tyrosine Sulfation (PSY) are still under investigation. Currently, there is a lack of accessible information concerning the PSY gene family in wheat. Results: Therefore, in this investigation, we identified 29 PSY genes in Triticum aestivum, with the aim of unraveling their significance in plant development processes and their response to a variety of stress conditions. Phylogenetic analysis showed that TaPSY genes clustered into five groups. Additionally, an analysis of the gene structure of TaPSYs displayed a conserved evolutionary path. The syntenic relationship demonstrated the 69 orthologous gene pairs in T. dicoccoides, Ae. tauschii, T. turgidum, and H. vulgare, respectively. Furthermore, the Ka/Ks analysis indicated that TaPSY genes have experienced purifying selection during their evolutionary processes. The promoters of TaPSY genes were found to contain numerous CAREs, and these elements are known to perform essential functions in various development processes, phytohormone responses, as well as defense and stress mechanisms. In addition, the identification of potential miRNAs targeting TaPSY genes was followed by an examination of their expression patterns across various tissues. Among the 29 TaPSY genes, twenty miRNAs were discovered to target eighteen of them. Moreover, TaPSY genes displayed a distinct expression across different tissues and stress conditions. Conclusions: Hence, these discoveries offer a significant reference point for forthcoming molecular investigations and hold promise for bolstering wheat yield and stress resilience through targeted genetic enhancements and strategic breeding approaches. Highlights: ➢ Signaling peptides, particularly those with Tyrosine Sulfation (PSY) gene family members, have been extensively researched in Arabidopsis. However, there is scarce information available regarding PSY genes in other crops such as wheat. ➢ In this study, we have identified 29 PSY genes in wheat for the first time, shedding light on their significance in plant development and stress response. ➢ Phylogenetic analysis categorized TaPSY genes into five clusters, exhibiting conserved gene structures and notable purifying selection. ➢ Further, the presence of multiple cis-acting regulatory elements (CAREs) in TaPSY promoters and out of the 29 TaPSY genes, 18 TaPSY genes were targeting by miRNAs highlight their roles in various developmental and stress processes. ➢ These discoveries offer invaluable insights for future molecular investigations aimed at boosting wheat yield and enhancing stress tolerance through targeted genetic improvements. [ABSTRACT FROM AUTHOR]

The GRAS gene family, responsible for encoding transcription factors, serves pivotal functions in plant development, growth, and responses to stress. The exploration of the GRAS gene family within the Orchidaceae has been comparatively limited, despite its identification and functional description in various plant species. This study aimed to conduct a thorough examination of the GRAS gene family in Cymbidum goeringii, focusing on its physicochemical attributes, phylogenetic associations, gene structure, cis-acting elements, and expression profiles under heat stress. The results show that a total of 54 CgGRASs were pinpointed from the genome repository and categorized into ten subfamilies via phylogenetic associations. Assessment of gene sequence and structure disclosed the prevalent existence of the VHIID domain in most CgGRASs, with around 57.41% (31/54) CgGRASs lacking introns. The Ka/Ks ratios of all CgGRASs were below one, indicating purifying selection across all CgGRASs. Examination of cis-acting elements unveiled the presence of numerous elements linked to light response, plant hormone signaling, and stress responsiveness. Furthermore, CgGRAS5 contained the highest quantity of cis-acting elements linked to stress response. Experimental results from RT-qPCR demonstrated notable variations in the expression levels of eight CgGRASs after heat stress conditions, particularly within the LAS, HAM, and SCL4/7 subfamilies. In conclusion, this study revealed the expression pattern of CgGRASs under heat stress, providing reference for further exploration into the roles of CgGRAS transcription factors in stress adaptation. [ABSTRACT FROM AUTHOR]

The generation of complex plant architectures depends on the interactions among different molecular regulatory networks that control the growth of cells within tissues, ultimately shaping the final morphological features of each structure. The regulatory networks underlying tissue growth and overall plant shapes are composed of intricate webs of transcriptional regulators which synergize or compete to regulate the expression of downstream targets. Transcriptional regulation is intimately linked to phytohormone networks as transcription factors (TFs) might act as effectors or regulators of hormone signaling pathways, further enhancing the capacity and flexibility of molecular networks in shaping plant architectures. Here, we focus on homeodomain-leucine zipper (HD-ZIP) proteins, a class of plant-specific transcriptional regulators, and review their molecular connections with hormonal networks in different developmental contexts. We discuss how HD-ZIP proteins emerge as key regulators of hormone action in plants and further highlight the fundamental role that HD-ZIP/hormone networks play in the control of the body plan and plant growth. [ABSTRACT FROM AUTHOR]

Clarifying the relationship between soil microorganisms and the plant-soil system is crucial for encouraging the sustainable development of ecosystems, as soil microorganisms serve a variety of functional roles in the plant-soil system. In this work, the influence mechanisms of significant soil microbial groups on the plant-soil system and their applications in environmental remediation over the previous 30 years were reviewed using a systematic literature review (SLR) methodology. The findings demonstrated that: (1) There has been a general upward trend in the number of publications on significant microorganisms, including bacteria, fungi, and archaea. (2) Bacteria and fungi influence soil development and plant growth through organic matter decomposition, nitrogen, phosphorus, and potassium element dissolution, symbiotic relationships, plant growth hormone production, pathogen inhibition, and plant resistance induction. Archaea aid in the growth of plants by breaking down low-molecular-weight organic matter, participating in element cycles, producing plant growth hormones, and suppressing infections. (3) Microorganismprinciples are utilized in soil remediation, biofertilizer production, denitrification, and phosphorus removal, e [ABSTRACT FROM AUTHOR]

Tillering directly determines the seed production and propagation capacity of clonal plants. However, the molecular mechanisms involved in the tiller development of clonal plants are still not fully understood. In this study, we conducted a proteome comparison between the tiller buds and stem node of a multiple-tiller mutant mtn1 (more tillering number 1) and a wild type of centipedegrass. The results showed significant increases of 29.03% and 27.89% in the first and secondary tiller numbers, respectively, in the mtn1 mutant compared to the wild type. The photosynthetic rate increased by 31.44%, while the starch, soluble sugar, and sucrose contents in the tiller buds and stem node showed increases of 13.79%, 39.10%, 97.64%, 37.97%, 55.64%, and 7.68%, respectively, compared to the wild type. Two groups comprising 438 and 589 protein species, respectively, were differentially accumulated in the tiller buds and stem node in the mtn1 mutant. Consistent with the physiological characteristics, sucrose and starch metabolism as well as plant hormone signaling were found to be enriched with differentially abundant proteins (DAPs) in the mtn1 mutant. These results revealed that sugars and plant hormones may play important regulatory roles in the tiller development in centipedegrass. These results expanded our understanding of tiller development in clonal plants. [ABSTRACT FROM AUTHOR]

Exploring plant behavior at the cellular scale in a minimally invasive manner is critical to understanding plant adaptation to the environment. Phytohormones play vital regulatory roles in multiple aspects of plant growth and development and acclimation to environmental changes. Since the biosynthesis, modification, transportation, and degradation of plant hormones in plants change with time and space, their content level and distribution are highly dynamic. To monitor the production, transport, perception, and distribution of phytohormones within undamaged tissues, we require qualitative and quantitative tools endowed with remarkably high temporal and spatial resolution. Fluorescent probes are regarded as excellent tools for widespread plant imaging because of their high sensitivity and selectivity, reproducibility, real-time in situ detection, and uncomplicated mechanism elucidation. In this review, we provide a systematical overview of the progress in the sensing and imaging of phytohormone fluorescent probes and fluorescently labeled phytohormones to their receptors in plants. Moreover, forthcoming viewpoints and possible applications of these fluorescent probes within the realm of plants are also presented. We hold the conviction that the new perspective brought by this paper can promote the development of fluorescent probes, enabling them to have better detection performance in plant hormone imaging. [ABSTRACT FROM AUTHOR]

Plant growth regulators (PGRs) are a critical regulatory factor that influences plant development and against abiotic or biotic stress. The chemical synthesis of phytohormone analogues represents an effective approach for developing novel PGRs with enhanced bioactivity, reduced costs, and simplified synthesis. This review provides a comprehensive examination of artificially synthesized PGRs (phytohormone structural analogues and functional analogues) over the past five years, emphasizing the synthesis strategy, bioactivity, structure-activity relationships, and target protein. This review argues that the synthesis of functional analogues of phytohormones represents a crucial in the advancement of novel PGRs, and optimization of synthetic procedures would greatly facilitate the commercialization of these PGRs. [ABSTRACT FROM AUTHOR]

Phytohormone is a key regulator of plant growth and development. It has important effects on plant under biotic and abiotic stresses. However, the dose control of phytohormone is always a difficult problem in the application process, which limits the application range of phytohormone. Nanotechnology, because of its characteristics of controlled release, targeted therapy, non-pollution, high adsorption, lower volatilization of active substances, and low dosage of drug, comes into researchers' vision. Nanomaterials were directly applicated on crops at the early stage, and then active substances, such as pesticides, were encapsulated with nanomaterials, also achieved good results in the field. Currently, more and more attentions have been paid to nano-enabled delivery of phytohormones to plants, and formed a new field in agriculture. In present work, we reviewed the existing literatures, focused on the important regulatory roles of phytohormones in plant growth and development and their application potential, and the development and application prospect of nanomaterials combined with phytohormones were also have been discussed. [ABSTRACT FROM AUTHOR]

Abscisic acid (ABA), a plant hormone, is crucial for regulating various physiological and developmental processes in plants, including adaptation to biotic and abiotic stresses. Recent advancements have significantly contributed to our understanding of ABA's biosynthetic pathway, transport, signaling pathway, and metabolism. To overcome the limitations of natural ABA, scientists have developed broad-spectrum and highly active agonists of ABA receptors. However, the practical application of these receptor agonists as agrochemicals still faces several challenges. On the other hand, some ABA antagonists have also been developed to differentiate the functional differences among various receptors more accurately. This can help design ABA agonists that can selectively activate specific physiological responses, thereby eliminating the undesired physiological effects induced by ABA. This paper aims to provide a comprehensive overview of the current ABA receptor agonists and antagonists to assist in developing novel ABA functional analogs with improved efficacy and simpler chemical structures that are suitable for agricultural applications. [ABSTRACT FROM AUTHOR]

Plants rely upon a diverse range of metabolites to control growth and development, and to overcome stress that results from suboptimal conditions. Karrikins (KARs) are a class of butenolide compounds found in smoke that stimulate seed germination and regulate various developmental processes in plants. KARs are perceived via a plant α/β-hydrolase called KARRIKIN INSENSITIVE2 (KAI2), which also functions as a receptor for a postulated phytohormone, provisionally termed KAI2 ligand (KL). Considered natural analogues of KL, KARs have been extensively studied for their effects on plant growth and their crosstalk with plant hormones. The perception and response pathway for KAR–KL signalling is closely related to that of strigolactones, another class of butenolides with numerous functions in regulating plant growth. KAR–KL signalling influences seed germination, seedling photomorphogenesis, root system architecture, abiotic stress responses, and arbuscular mycorrhizal symbiosis. Here, we summarize current knowledge of KAR–KL signalling, focusing on its role in plant development, its effects on stress tolerance, and its interaction with other signalling mechanisms. [ABSTRACT FROM AUTHOR]

Cytokinin (CK) is a plant hormone that plays crucial roles in regulating plant growth and development. CK-deficient plants are widely used as model systems for investigating the numerous physiological roles of CK. Since it was previously shown that transgenic or mutant CK-deficient Arabidopsis and Centaurium plants show superior tolerance to salinity, we examined the tolerance of three CK-deficient potato lines overexpressing the Arabidopsis thaliana CYTOKININ OXIDASE/DEHYDROGENASE2 (AtCKX2) gene to 50 mM, 100 mM, 150 mM, and 200 mM NaCl applied in vitro. Quantification of visible salinity injury, rooting and acclimatization efficiency, shoot growth, water saturation deficit, and chlorophyll content confirmed that the CK-deficient potato plants were more tolerant to low (50 mM) and moderate (100 mM) NaCl concentrations, but exhibited increased sensitivity to severe salinity stress (150 and 200 mM NaCl) compared to nontransformed control plants. These findings were corroborated by the data distribution patterns according to principal component analysis. Quantification of the activity of superoxide dismutases, peroxidases, and catalases revealed an impaired ability of AtCKX2-transgenic lines to upregulate the activity of antioxidant enzymes in response to salinity, which might contribute to the enhanced sensitivity of these potato lines to severe salt stress. Our results add complexity to the existing knowledge on the regulation of salinity tolerance by CK, as we show for the first time that CK-deficient plants can exhibit reduced rather than increased tolerance to severe salt stress. [ABSTRACT FROM AUTHOR]

Plants constantly perceive and process environmental signals and balance between the energetic demands of growth and defense. Growth arrest upon pathogen attack was previously suggested to result from a redirection of the plants' metabolic resources towards the activation of plant defense. The energy sensor Target of Rapamycin (TOR) kinase is a conserved master coordinator of growth and development in all eukaryotes. Although TOR is positioned at the interface between development and defense, little is known about the mechanisms by which TOR may potentially regulate the relationship between these two modalities. The plant hormones cytokinin (CK) and gibberellin (GA) execute various aspects of plant development and defense. The ratio between CK and GA was reported to determine the outcome of developmental programmes. Here, investigating the interplay between TOR‐mediated development and TOR‐mediated defense in tomato, we found that TOR silencing resulted in rescue of several different aberrant developmental phenotypes, demonstrating that TOR is required for the execution of developmental cues. In parallel, TOR inhibition enhanced immunity in genotypes with a low CK/GA ratio but not in genotypes with a high CK/GA ratio. TOR‐inhibition mediated disease resistance was found to depend on developmental status, and was abolished in strongly morphogenetic leaves, while being strongest in mature, differentiated leaves. CK repressed TOR activity, suggesting that CK‐mediated immunity may rely on TOR downregulation. At the same time, TOR activity was promoted by GA, and TOR silencing reduced GA sensitivity, indicating that GA signalling requires normal TOR activity. Our results demonstrate that TOR likely acts in concert with CK and GA signalling, executing signalling cues in both defense and development. Thus, differential regulation of TOR or TOR‐mediated processes could regulate the required outcome of development‐defense prioritisation. Summary Statement: Target of Rapamycin (TOR) is positioned at the interface between development and defense, but little is known about the mechanisms by which TOR may regulate shifts between them. Here, we demonstrate that TOR likely acts in concert with cytokinin and gibberellin to execute signalling cues in both defense and development. [ABSTRACT FROM AUTHOR]

The International Journal of Molecular Sciences has published a special issue on phytohormones and their role in plant growth and development. The articles cover various aspects of hormonal control in plants, including flower opening and closure, fruit ripening, and seed maturation. The collection explores classical hormones like cytokinins and auxins, as well as newer regulators like strigalactones and melatonin. The articles discuss the impact of hormonal control on plant resistance to stress and highlight the importance of hormonal balance in physiological processes. The document provides a list of scientific articles on topics such as strigolactone biosynthesis, cytokinin regulation of stomatal conductance, auxin's role in plant development and stress adaptation, and electrical signaling mechanisms in plants. [Extracted from the article]

Gibberellin (GA) is an important plant hormone that is involved in various physiological processes during plant development. Sweet cherries planted in southern China have always encountered difficulty in bearing fruit. In recent years, gibberellin has successfully solved this problem, but there has also been an increase in malformed fruits. This study mainly explores the mechanism of malformed fruit formation in sweet cherries. By analyzing the synthesis pathway of gibberellin using metabolomics and transcriptomics, the relationship between gibberellin and the formation mechanism of deformed fruit was preliminarily determined. The results showed that the content of GA3 in malformed fruits was significantly higher than in normal fruits. The differentially expressed genes in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were mainly enriched in pathways such as "plant hormone signal transduction", "diterpenoid biosynthesis", and "carotenoid biosynthesis". Using Quantitative Real-Time Reverse Transcription PCR (qRT-PCR) analysis, the gibberellin hydrolase gene GA2ox and gibberellin synthase genes GA20ox and GA3ox were found to be significantly up-regulated. Therefore, we speculate that the formation of malformed fruits in sweet cherries may be related to the accumulation of GA3. This lays the foundation for further research on the mechanism of malformed sweet cherry fruits. [ABSTRACT FROM AUTHOR]

B3 family transcription factors play an essential regulatory role in plant growth and development processes. This study performed a comprehensive analysis of the B3 family transcription factor in longan (Dimocarpus longan Lour.), and a total of 75 DlB3 genes were identified. DlB3 genes were unevenly distributed on the 15 chromosomes of longan. Based on the protein domain similarities and functional diversities, the DlB3 family was further clustered into four subgroups (ARF, RAV, LAV, and REM). Bioinformatics and comparative analyses of B3 superfamily expression were conducted in different light and with different temperatures and tissues, and early somatic embryogenesis (SE) revealed its specific expression profile and potential biological functions during longan early SE. The qRT-PCR results indicated that DlB3 family members played a crucial role in longan SE and zygotic embryo development. Exogenous treatments of 2,4-D (2,4-dichlorophenoxyacetic acid), NPA (N-1-naphthylphthalamic acid), and PP333 (paclobutrazol) could significantly inhibit the expression of the DlB3 family. Supplementary ABA (abscisic acid), IAA (indole-3-acetic acid), and GA3 (gibberellin) suppressed the expressions of DlLEC2, DlARF16, DlTEM1, DlVAL2, and DlREM40, but DlFUS3, DlARF5, and DlREM9 showed an opposite trend. Furthermore, subcellular localization indicated that DlLEC2 and DlFUS3 were located in the nucleus, suggesting that they played a role in the nucleus. Therefore, DlB3s might be involved in complex plant hormone signal transduction pathways during longan SE and zygotic embryo development. [ABSTRACT FROM AUTHOR]

Strains of the ascomycetous yeast Metschnikowia pulcherrima isolated from the internal tissues of fruits were evaluated for phytohormonal activity. IAA production in the culture liquid was determined by the chromatographic method (HPLC-UV). The production of the phytohormones zeatin and gibberellin (GA3) in the culture liquid was determined by a chromatographic method using a quadrupole time-of-flight mass spectrometry detector (Q- TOF LC / MS). IAA and zeatin were detected in the culture liquid of all strains studied. Synthesis of gibberellin (GA3) was detected in only 5 of 18 strains examined. On average, the strains showed the highest activity in the synthesis of IAA (6.668 µg/mL and 2.135 mg/g). Zeatin content was 3 orders of magnitude lower (0.365 ng/mL and 0.129 µg/g) and GA3 content was 4 orders of magnitude lower (0.076 ng/mL and 0.027 µg/g). According to our results, the yeast M. pulcherrima is not an active producer of zeatin and GA3 in amounts relevant to the plant. On the other hand, the average level of IAA synthesis detected in M. pulcherrima strains in this study is within the range of concentrations that can stimulate plant development and growth. Thus, endophytic strains of M. pulcherrima that produce plant-relevant levels of IAA could be improved to increase their synthesis ability and used as plant growth promoters in agricultural crops. [ABSTRACT FROM AUTHOR]

Salt stress is one of the main environmental factors affecting plant growth. Photosynthesis, which provides the energy needed for plant growth and development, will be severely restricted under salt stress. Strigolactones (SLs), a class of carotenoid‐derived phytohormone, play an important role in regulating plant growth and responding to multiple biotic and abiotic stresses. In this study, we investigated the role of rac‐GR24 (a synthetic SLs analog) in the amelioration of salt stress in the photosynthesis of alfalfa. These results showed that rac‐GR24 treatment could increase the content of soluble sugar and soluble protein, increase superoxide dismutase, catalase, and peroxidase activity and reduce the content of malondialdehyde in alfalfa leaves, thus relieving the damage caused by salt stress in alfalfa leaves. Moreover, rac‐GR24 treatment could also regulate the K+/Na+ homeostasis, improved stomatal conductance and increased chlorophyll content, which improved the photosynthesis limited by salt stress. The expression levels of selected gene for photosynthesis and antioxidants were consistent with the physiological performance. Our study indicated that rac‐GR24 could alleviate the negative effects on photosynthesis of alfalfa under salt stress. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO) and nitric oxide (NO) are signal molecules that enhance plant adaptation to environmental stimuli. Auxin is an essential phytohormone for plant growth and development. CO and NO play crucial roles in modulating the plant’s response to iron deficiency. Iron deficiency leads to an increase in the activity of heme oxygenase (HO) and the subsequent generation of CO. Additionally, it alters the polar subcellular distribution of Pin-Formed 1 (PIN1) proteins, resulting in enhanced auxin transport. This alteration, in turn, leads to an increase in NO accumulation. Furthermore, iron deficiency enhances the activity of ferric chelate reductase (FCR), as well as the expression of the Fer-like iron deficiency-induced transcription factor 1 (FIT) and the ferric reduction oxidase 2 (FRO2) genes in plant roots. Overexpression of the long hypocotyl 1 (HY1) gene, which encodes heme oxygenase, or the CO donor treatment resulted in enhanced basipetal auxin transport, higher FCR activity, and the expression of FIT and FRO2 genes under Fe deficiency. Here, a potential mechanism is proposed: CO and NO interact with auxin to address iron deficiency stress. CO alters auxin transport, enhancing its accumulation in roots and up-regulating key iron-related genes like FRO2 and IRT1. Elevated auxin levels affect NO signaling, leading to greater sensitivity in root development. This interplay promotes FCR activity, which is crucial for iron absorption. Together, these molecules enhance iron uptake and root growth, revealing a novel aspect of plant physiology in adapting to environmental stress. [ABSTRACT FROM AUTHOR]

Bud dormancy and release are essential phenomena that greatly assist in adapting to adverse growing conditions and promoting the holistic growth and development of perennial plants. The dormancy and release process of buds in temperate perennial trees involves complex interactions between physiological and biochemical processes influenced by various environmental factors, representing a meticulously orchestrated life cycle. In this review, we summarize the role of phytohormones and their crosstalk in the establishment and release of bud dormancy. External environmental factors, such as light and temperature, play a crucial role in regulating bud germination. We also highlight the mechanisms of how light and temperature are involved in the regulation of bud dormancy by modulating phytohormones. Moreover, the role of nutrient factors, including sugar, in regulating bud dormancy is also discussed. This review provides a foundation for enhancing our understanding of plant growth and development patterns, fostering agricultural production, and exploring plant adaptive responses to adversity. [ABSTRACT FROM AUTHOR]

SUMMARY: Brassinosteroids (BRs) are a class of steroid phytohormones that control various aspects of plant growth and development. Several transcriptional factors (TFs) have been suggested to play roles in BR signaling. However, their possible relationship remains largely unknown. Here, we identified a rice mutant dwarf and low‐tillering 2 (dlt2) with altered plant architecture, increased grain width, and reduced BR sensitivity. DLT2 encodes a GIBBERELLIN INSENSITIVE (GAI)‐REPRESSOR OF GAI (RGA)‐SCARECROW (GRAS) TF that is mainly localized in the nucleus and has weak transcriptional activity. Our further genetic and biochemical analyses indicate that DLT2 interacts with two BR‐signaling‐related TFs, DLT and BRASSINAZOLE‐RESISTANT 1, and probably modulates their transcriptional activity. These findings imply that DLT2 is implicated in a potentially transcriptional complex that mediates BR signaling and rice development and suggests that DLT2 could be a potential target for improving rice architecture and grain morphology. This work also sheds light on the role of rice GRAS members in regulating numerous developmental processes. [ABSTRACT FROM AUTHOR]

In concert with other phytohormones, auxin regulates plant growth and development. However, how auxin and other phytohormones coordinately regulate distinct processes is notfully understood. In this work, we uncover an auxin-abscisic acid (ABA) interaction module in Arabidopsis that is specific to coordinating activities of these hormones in the hypocotyl. From our forward genetics screen, we determine that ABA biosynthesis is required for the full effects of auxin on hypocotyl elongation. Our data also suggest that ABA biosynthesis is not required for the inhibitory effects of auxin treatment on root elongation. Our transcriptome analysis identified distinct auxin-responsive genes in root and shoot tissues, which is consistent with differential regulation of growth in these tissues. Further, our data suggest that many gene targets repressed upon auxin treatment require an intact ABA pathway for full repression. Our results support a model in which auxin stimulates ABA biosynthesis to fully regulate hypocotyl elongation. [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]

Plants are exposed to a variety of abiotic stresses; these stresses have profound effects on plant growth, survival, and productivity. Tolerance and adaptation to stress require sophisticated stress sensing, signaling, and various regulatory mechanisms. The plant hormone auxin is a key regulator of plant growth and development, playing pivotal roles in the integration of abiotic stress signals and control of downstream stress responses. In this review, we summarize and discuss recent advances in understanding the intersection of auxin and abiotic stress in plants, with a focus on temperature, salt, and drought stresses. We also explore the roles of auxin in stress tolerance and opportunities arising for agricultural applications. [ABSTRACT FROM AUTHOR]

Plants, being sessile, have developed complex signaling and response mechanisms to cope with biotic and abiotic stressors. Recent investigations have revealed the significant contribution of phytohormones in enabling plants to endure unfavorable conditions. Among these phytohormones, jasmonic acid (JA) and its derivatives, collectively referred to as jasmonates (JAs), are of particular importance and are involved in diverse signal transduction pathways to regulate various physiological and molecular processes in plants, thus protecting plants from the lethal impacts of abiotic and biotic stressors. Jasmonic acid has emerged as a central player in plant defense against biotic stress and in alleviating multiple abiotic stressors in plants, such as drought, salinity, vernalization, and heavy metal exposure. Furthermore, as a growth regulator, JA operates in conjunction with other phytohormones through a complex signaling cascade to balance plant growth and development against stresses. Although studies have reported the intricate nature of JA as a biomolecular entity for the mitigation of abiotic stressors, their underlying mechanism and biosynthetic pathways remain poorly understood. Therefore, this review offers an overview of recent progress made in understanding the biosynthesis of JA, elucidates the complexities of its signal transduction pathways, and emphasizes its pivotal role in mitigating abiotic and biotic stressors. Moreover, we also discuss current issues and future research directions for JAs in plant stress responses. [ABSTRACT FROM AUTHOR]