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Brassinosteroids (BRs) and jasmonic acid (JA) are known to be involved in regulating plant responses to cadmium (Cd) stress. However, their specific roles and interaction in this process remain unclear. In this study, we discovered that exogenous BR alleviated Cd-mediated growth inhibition of rice seedlings. Enhanced Cd tolerance was also observed in m107, a BR-overproduction mutant. Phenotypic analysis of genetic materials involved in BR signaling confirmed the positive role of BR in regulating rice response to Cd toxicity. OsDLT, a key component in the BR signaling pathway, was found to be crucial for BR-mediated Cd tolerance. Further analysis demonstrated that activation of the BR pathway reduced the accumulation of Cd and reactive oxygen species (ROS) by modulating the expression of genes associated with Cd transport and ROS scavenging. Interestingly, transcriptome analysis indicated that the JA pathway was enriched in OsDLT-regulated differently expressed genes (DEGs). Gene expression and hormone assays showed that BR promoted the expression of JA pathway genes and JA levels in plants. Moreover, BR-induced tolerance was compromised in the JA signaling-deficient mutant osmyc2, suggesting that BR-mediated Cd resistance depends on the activation of the JA signaling pathway. Overall, our study revealed the synergistic interaction between BR and JA pathways in rice response to Cd stress, providing insights into the complex hormonal interplay in plant tolerance to heavy metals.
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Brassinosteroids (BRs) are well known for their important role in the regulation of plant growth and development. Plants with deficiency in BR signaling show delayed plant development and exhibit late flowering phenotypes. However, the precise mechanisms involved in this process require investigation. In this study, we cloned homologs of BRASSINOSTEROID INSENSITIVE 2 (SlBIN2), the GSK3-like protein kinase in tomato (Solanum lycopersicum). We characterized growth-related processes and phenotypic changes in the transgenic lines and found that SlBIN2s transgenic lines have delayed development and slow growing phenotypes. SlBIN2s work redundantly to negatively regulate BR signaling in tomato. Furthermore, the transcription factor SlBIN2.1-INTERACTING MYB-LIKE 1 (SlBIML1) was identified as a downstream substrate of SlBIN2s that SlBIN2s interact with and phosphorylate to synergistically regulate tomato developmental processes. Specifically, SlBIN2s modulated protein stability of SlBIML1 by phosphorylating multiple amino acid residues, including the sites Thr266 and Thr280. This study reveals a branch of the BR signaling pathway that regulates the vegetative growth phase and delays floral transition in tomato without the feedback affecting BR signaling. This information enriches our understanding of the downstream transduction pathway of BR signaling and provides potential targets for adjusting tomato flowering time.
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Steroid 5α-reductase1/2 (SRD5A1/2) is an androgen protein that resembles the plant DET2 and is responsible for the conversion of testosterone to the more active dihydrotestosterone (DHT). Both proteins share functional homology and have a common ancestor. In mammals, the SRD5A1/2 can reduce a wide range of steroid substrates, such as testosterone, progesterone, and aldosterone, by reducing the Δ4 in ring A. The plant DET2 catalyzes the conversion of campesterol (CR) to campestanol (CN) by reducing the Δ5 in ring B during brassinosteroid (BRs) biosynthesis. We compared the evolution, structural, and functional homology of the SRD5A family and tried to identify the origin and functional diversification of duplicated genes in eukaryotes. We presented a detailed phylogeny that includes representative species from all eukaryotic groups. Our study indicated that protist is a common ancestor for all the subgroups of the SRD5A family. However, not all protists possess SRD5A1/2/DET2 or other homologs, suggesting that some protists may have lost these gene families during evolution. Lineage-specific duplication leads Caenorhabditis elegance to have three SRD5A1/2 genes but none was found in Drosophila melanogaster. We also identified a new subclass, DET2-like (DET2L), in plants that closely resemble SRD5A1/2/DET2. The hypothesized reductase DET2L showed no phenotypic enhancement when expressed in Arabidopsis det 2 mutants, suggesting its possible role in the reduction of polyprenol or other substrates.
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Cotton fiber (Gossypium hirsutum) serves as an ideal model for investigating the molecular mechanisms of plant cell elongation at the single-cell level. Brassinosteroids (BRs) play a crucial role in regulating plant growth and development. However, the mechanism by which BR influences cotton fiber elongation remains incompletely understood. In this study, we identified EXORDIUM-like (GhEXL3) through transcriptome analysis of fibers from BR-deficient cotton mutant pagoda 1 (pag1) and BRI1-EMS-SUPPRESSOR 1 (GhBES1.4, encoding a central transcription factor of BR signaling) overexpression cotton lines. Knockout of GhEXL3 using CRISPR/Cas9 was found to impede cotton fiber elongation, while its overexpression promoted fiber elongation, suggesting a positive regulatory function for GhEXL3 in fiber elongation. Furthermore, in vitro ovule culture experiments revealed that the overexpression of GhEXL3 partially counteracted the inhibitory effects of brassinazole (BRZ) on cotton fiber elongation, providing additional evidence of GhEXL3 involvement in BR signaling pathways. Moreover, our findings demonstrate that GhBES1.4 directly binds to the E-box (CACGTG) motif in the GhEXL3 promoter region and enhances its transcription. RNA-seq analysis revealed that overexpression of GhEXL3 upregulated the expression of EXPs, XTHs, and other genes associated with fiber cell elongation. Overall, our study contributes to understanding the mechanism by which BR regulates the elongation of cotton fibers through the direct modulation of GhEXL3 expression by GhBES1.4.
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Brassinosteroids (BRs) are an essential group of plant hormones regulating numerous aspects of plant growth, development, and stress responses. BRI1, along with its co-receptor BAK1, are involved in brassinosteroid sensing and early events in the BR signal transduction cascade. Mutational analysis of a particular gene is a powerful strategy for investigating its biochemical role. Molecular genetic studies, predominantly in Arabidopsis thaliana, but progressively in numerous other plants, have identified many mutants of the BRI1 gene and its orthologs to gain insight into its structure and function. So far, the plant kingdom has identified up to 40 bri1 alleles in Arabidopsis and up to 30 bri1 orthologs in different plants. These alleles exhibit phenotypes that are identical in terms of development and growth. Here, we have summarized bri1 alleles in Arabidopsis and its orthologs present in various plants including monocots and dicots. We have discussed the possible mechanism responsible for the specific allele. Finally, we have briefly debated the importance of these alleles in the research field and the agronomically valuable traits they offer to improve plant varieties.
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Alelos , Proteínas de Arabidopsis , Arabidopsis , Brasinoesteroides , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Brasinoesteroides/metabolismo , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Regulación de la Expresión Génica de las Plantas , Mutación , Transducción de Señal/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
Temperature affects plant growth and geographical distribution. Cold stress occurs when temperatures fall below the physiologically optimal range for plants, causing permanent and irreversible damage to plant growth, development, and production. Brassinosteroids (BRs) are steroid hormones that play an important role in plant growth and various stress responses. Recent studies have shown that low temperatures affect BR biosynthesis in many plant species and that BR signaling is involved in the regulation of plant tolerance to low temperatures, both in the CBF-dependent and CBF-independent pathways. These two regulatory pathways correspond to transient and acclimation responses of low temperature, respectively. The crosstalk between BRs and other hormones is a significant factor in low-temperature tolerance. We provide an overview of recent developments in our knowledge of BRs' function in plant responses to cold stress and how they interact with other plant hormones in this review.
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KEY MESSAGE: Exogenous application of 24-epibrassinolide can alleviate oxidative damage, improve photosynthetic capacity, and regulate carbon and nitrogen assimilation, thus improving the tolerance of grapevine (Vitis vinifera L.) to drought stress. Brassinosteroids (BRs) are a group of plant steroid hormones in plants and are involved in regulating plant tolerance to drought stress. This study aimed to investigate the regulation effects of BRs on the carbon and nitrogen metabolism in grapevine under drought stress. The results indicated that drought stress led to the accumulation of superoxide radicals and hydrogen peroxide and an increase in lipid peroxidation. A reduction in oxidative damage was observed in EBR-pretreated plants, which was probably due to the improved antioxidant concentration. Moreover, exogenous EBR improved the photosynthetic capacity and sucrose phosphate synthase activity, and decreased the sucrose synthase, acid invertase, and neutral invertase, resulting in improved sucrose (190%) and starch (17%) concentrations. Furthermore, EBR pretreatment strengthened nitrate reduction and ammonium assimilation. A 57% increase in nitrate reductase activity and a 13% increase in glutamine synthetase activity were observed in EBR pretreated grapevines. Meanwhile, EBR pretreated plants accumulated a greater amount of proline, which contributed to osmotic adjustment and ROS scavenging. In summary, exogenous EBR enhanced drought tolerance in grapevines by alleviating oxidative damage and regulating carbon and nitrogen metabolism.
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Brasinoesteroides , Resistencia a la Sequía , Fotosíntesis , Esteroides Heterocíclicos , Vitis , Antioxidantes/metabolismo , Antioxidantes/farmacología , Brasinoesteroides/metabolismo , Brasinoesteroides/farmacología , Carbono/metabolismo , Glucosiltransferasas/metabolismo , Glutamato-Amoníaco Ligasa/metabolismo , Peróxido de Hidrógeno/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Nitrato-Reductasa/metabolismo , Nitrógeno/metabolismo , Estrés Oxidativo/efectos de los fármacos , Fotosíntesis/efectos de los fármacos , Reguladores del Crecimiento de las Plantas/metabolismo , Reguladores del Crecimiento de las Plantas/farmacología , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Esteroides Heterocíclicos/metabolismo , Esteroides Heterocíclicos/farmacología , Estrés Fisiológico/efectos de los fármacos , Vitis/efectos de los fármacos , Vitis/metabolismo , Vitis/fisiologíaRESUMEN
Plant growth regulators are routinely added to in vitro culture media to foster the growth and differentiation of the cells, tissues, and organs. However, while the literature on usage of the more common auxins, cytokinins, gibberellins, abscisic acid, and ethylene is vast, other compounds that also have shown a growth-regulating activity have not been studied as frequently. Such substances are also capable of modulating the responses of plant cells and tissues in vitro by regulating their growth, differentiation, and regeneration competence, but also by enhancing their responses toward biotic and abiotic stress agents and improving the production of secondary metabolites of interest. This chapter will discuss the in vitro effects of several of such less frequently added plant growth regulators, including brassinosteroids (BRS), strigolactones (SLs), phytosulfokines (PSKs), methyl jasmonate, salicylic acid (SA), sodium nitroprusside (SNP), hydrogen sulfite, various plant growth retardants and inhibitors (e.g., ancymidol, uniconazole, flurprimidol, paclobutrazol), and polyamines.
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Reguladores del Crecimiento de las Plantas , Reguladores del Crecimiento de las Plantas/farmacología , Reguladores del Crecimiento de las Plantas/metabolismo , Técnicas de Cultivo de Tejidos/métodos , Brasinoesteroides/farmacología , Brasinoesteroides/metabolismo , Desarrollo de la Planta/efectos de los fármacos , Plantas/metabolismo , Plantas/efectos de los fármacos , Lactonas/farmacología , Lactonas/metabolismo , Oxilipinas/farmacología , Oxilipinas/metabolismo , Ciclopentanos/farmacología , Ciclopentanos/metabolismo , Ácido Salicílico/farmacología , Ácido Salicílico/metabolismo , Acetatos/farmacología , Acetatos/metabolismoRESUMEN
Bri1-EMS Suppressor 1 (BES1) and Brassinazole Resistant 1 (BZR1) are two key transcription factors in the brassinosteroid (BR) signaling pathway, serving as crucial integrators that connect various signaling pathways in plants. Extensive genetic and biochemical studies have revealed that BES1 and BZR1, along with other protein factors, form a complex interaction network that governs plant growth, development, and stress tolerance. Among the interactome of BES1 and BZR1, several proteins involved in posttranslational modifications play a key role in modifying the stability, abundance, and transcriptional activity of BES1 and BZR1. This review specifically focuses on the functions and regulatory mechanisms of BES1 and BZR1 protein interactors that are not involved in the posttranslational modifications but are crucial in specific growth and development stages and stress responses. By highlighting the significance of the BZR1 and BES1 interactome, this review sheds light on how it optimizes plant growth, development, and stress responses.
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Proteínas de Arabidopsis , Proteínas de Unión al ADN , Regulación de la Expresión Génica de las Plantas , Proteínas Nucleares , Desarrollo de la Planta , Estrés Fisiológico , Desarrollo de la Planta/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Factores de Transcripción/metabolismo , Brasinoesteroides/metabolismo , Transducción de Señal , Procesamiento Proteico-Postraduccional , Unión ProteicaRESUMEN
Inflorescence architecture is highly variable across plant lineages yet is critical for facilitating reproductive success. The capitulum-type inflorescence of the Asteraceae is marked as a key morphological innovation that preceded the family's diversification and expansion. Despite its evolutionary significance, our understanding of capitulum development and evolution is limited. This review highlights our current perspective on capitulum evolution through the lens of both its molecular and developmental underpinnings. We attempt to summarize our understanding of the capitulum by focusing on two key characteristics: patterning (arrangement of florets on a capitulum) and floret identity specification. Note that these two features are interconnected such that the identity of florets depends on their position along the inflorescence axis. Phytohormones such as auxin seemingly determine both pattern progression and floret identity specification through unknown mechanisms. Floret morphology in a head is controlled by differential expression of floral symmetry genes regulating floret identity specification. We briefly summarize the applicability of the ABCE quartet model of flower development in regulating the floret organ identity of a capitulum in Asteraceae. Overall, there have been promising advancements in our understanding of capitula; however, comprehensive functional genetic analyses are necessary to fully dissect the molecular pathways and mechanisms involved in capitulum development.
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Asteraceae , Asteraceae/genética , Asteraceae/crecimiento & desarrollo , Inflorescencia/genética , Inflorescencia/crecimiento & desarrollo , Regulación de la Expresión Génica de las Plantas , Evolución Biológica , Flores/crecimiento & desarrollo , Flores/genéticaRESUMEN
Salinity stress adversely impacts plant growth and development. Plant growth-promoting rhizobacteria (PGPR) are known to confer salinity stress tolerance in plants through several mechanisms. Here, we report the role of an abiotic stress-tolerant PGPR strain, Bacillus endophyticus J13, in promoting salinity stress tolerance in Arabidopsis thaliana, by elucidating its impact on physiological responses, polyamine (PA) and ethylene biosynthesis, and brassinosteroid signaling. Physiological analysis revealed that J13 can significantly improve the overall plant growth under salt stress by increasing the biomass, relative water content, and chlorophyll content, decreasing membrane damage and lipid peroxidation, and modulating proline homeostasis in plants. Evaluation of shoot polyamine levels upon J13 inoculation revealed an overall decrease in the levels of the three major PAs, putrescine (Put), spermidine (Spd), and spermine (Spm), under non-stressed conditions. Salt stress significantly increased the levels of Put and Spm, while decreasing the Spd levels in the plants. J13 inoculation under salt-stressed conditions, significantly decreased the Put levels, bringing them closer to those of the untreated control plants, whereas Spd and Spm levels did not change relative to the non-inoculated salt-stressed plants. The modulation of PA levels was accompanied by changes in the expressions of key PA biosynthetic genes under all treatments. Among the ethylene biosynthetic genes that we studied, ACS1 was induced by J13 inoculation under salt stress. J13 inoculation under salt stress resulted in the modulation of the expressions of BR-signaling genes, upregulating the expressions of the positive regulators of BR-signaling (BZR1 and BES2) and downregulating that of the negative regulator (BIN2). Our results provide a new avenue for J13-mediated salt stress amelioration in Arabidopsis, via tight control of polyamine and ethylene biosynthesis and enhanced brassinosteroid signaling.
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Arabidopsis , Bacillus , Brasinoesteroides , Etilenos , Poliaminas , Tolerancia a la Sal , Transducción de Señal , Arabidopsis/fisiología , Arabidopsis/microbiología , Arabidopsis/genética , Etilenos/metabolismo , Etilenos/biosíntesis , Brasinoesteroides/metabolismo , Poliaminas/metabolismo , Bacillus/fisiología , Bacillus/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
Brassinosteroids (BRs) can regulate various processes in plant development and defense against environmental stress. In this study, the contribution of BRs in the degradation of isoproturon (IPU) in rice has been established. IPU has a significant effect on rice growth, chlorophyll content, and membrane permeability. When treated with 1.0 µmol/L 24-epibrassinolide (EBR), a BR analogue, the associated symptoms of rice poisoning were alleviated as the IPU levels in the rice and growth media were decreased. In the presence of EBR, the activities of several IPU-related detoxification enzymes were enhanced to cope with the stress due to IPU. An RNA-sequencing (RNA-Seq) has been performed to determine the variation of transcriptomes and metabolic mechanisms in rice treated with EBR, IPU, or IPU+EBR. Some of the differentially expressed genes (DEGs) were Phase I-III reaction components of plants, such as cytochrome P450 (CYP450), glutathione S-transferase (GST), glycosyltransferases (GTs), and the ATP-binding cassette transporter (ABC transporter). The expression of some signal transduction genes was significantly up-regulated. The relative content of low-toxicity IPU metabolites increased due to the presence of EBR as determined by UPLC/Q-TOF-MS/MS. The IPU metabolic pathways include enzyme-catalyzed demethylation, hydroxylation, hydrolysis, glycosylation, and amino acid conjugation processes. The results suggest that EBR plays a key role in the degradation and detoxification of IPU. This study has provided evidence that BRs regulate the metabolism and detoxification of IPU in rice, and offers a new approach to ensuring cleaner crops by eliminating pesticide residues in the environment.
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Brasinoesteroides , Oryza , Compuestos de Fenilurea , Esteroides Heterocíclicos , Oryza/genética , Oryza/efectos de los fármacos , Esteroides Heterocíclicos/farmacología , Compuestos de Fenilurea/toxicidad , Herbicidas/toxicidad , Estrés Fisiológico/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Clorofila/metabolismoRESUMEN
KEY MESSAGE: Two significant studies have unveiled the pivotal role of BR regulation in shaping distinct features: the clustered-spikelet architecture in rice and the superior semi-dwarf stature in wheat.
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Brasinoesteroides , Productos Agrícolas , Oryza , Triticum , Brasinoesteroides/metabolismo , Oryza/genética , Oryza/crecimiento & desarrollo , Oryza/metabolismo , Productos Agrícolas/genética , Productos Agrícolas/crecimiento & desarrollo , Triticum/genética , Triticum/crecimiento & desarrollo , Triticum/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
Global warming has adversely affected Picea abies (L.) H. Karst. forests in Europe, prompting the need for innovative forest-breeding strategies. Somatic embryogenesis (SE) offers promise but requires protocol refinement. Understanding the molecular mechanisms governing somatic embryo development is essential, as oxidative stress plays a crucial role in SE regulation. Ascorbic acid (ASA), is a vital antioxidant that can potentially control oxidative stress. In the present study, we normalized ASA concentrations in induction and proliferation media to enhance embryogenic tissue (ET) regeneration and proliferation capacity of mature explants. The media were supplemented with ASA at 0 mg l-1, 25 mg l-1, 50 mg l-1, 100 mg l-1, and 200 mg l-1. The accumulation of hydrogen peroxide (H2O2) and endogenous phytohormones, including auxins, cytokinins, brassinosteroids, abscisic acid, and gibberellin, was measured in non-embryonic calli and ET. Subsequently, their impact on ET induction and multiplication was analyzed. Our results demonstrate that application of ASA at concentrations of 25 mg l-1 and 200 mg l-1 led to increased H2O2 levels, potentially inducing oxidative stress while simultaneously reducing the levels of all endohormone groups. Notably, the highest ET induction frequency (approximately 70%) was observed for ASA at 50 mg l-1. These findings will enhance SE induction procedures, particularly in more resistant explants, underscoring the significance of ASA application to culture media.
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Branch number is one of the most important agronomic traits of fruit trees such as peach. Little is known about how LncRNA and/or miRNA modules regulate branching through transcription factors. Here, we used molecular and genetic tools to clarify the molecular mechanisms underlying brassinosteroid (BR) altering plant branching. We found that the number of sylleptic branch and BR content in pillar peach ('Zhaoshouhong') was lower than those of standard type ('Okubo'), and exogenous BR application could significantly promote branching. PpTCP4 expressed great differentially comparing 'Zhaoshouhong' with 'Okubo'. PpTCP4 could directly bind to DWARF2 (PpD2) and inhibited its expression. PpD2 was the only one differentially expressed key gene in the path of BR biosynthesis. At the same time, PpTCP4 was identified as a target of miR6288b-3p. LncRNA1 could act as the endogenous target mimic of miR6288b-3p and repress expression of miR6288b-3p. Three deletions and five SNP sites of lncRNA1 promoter were found in 'Zhaoshouhong', which was an important cause of different mRNA level of PpTCP4 and BR content. Moreover, overexpressed PpTCP4 significantly inhibited branching. A novel mechanism in which the lncRNA1-miR6288b-3p-PpTCP4-PpD2 module regulates peach branching number was proposed.
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Brasinoesteroides , Regulación de la Expresión Génica de las Plantas , MicroARNs , Proteínas de Plantas , Prunus persica , ARN Largo no Codificante , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Prunus persica/genética , Prunus persica/crecimiento & desarrollo , Prunus persica/metabolismo , Brasinoesteroides/metabolismo , Brasinoesteroides/biosíntesis , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regiones Promotoras Genéticas/genética , Secuencia de Bases , Polimorfismo de Nucleótido Simple/genética , Genes de PlantasRESUMEN
Cucumber plants are highly susceptible to the hemibiotroph oomycete Phytophthora melonis. However, the mechanism of resistance to cucumber blight remains poorly understood. Here, we demonstrated that cucumber plants with impairment in the biosynthesis of brassinosteroids (BRs) or gibberellins (GAs) were more susceptible to P. melonis. By contrast, increasing levels of endogenous BRs or exogenously application of 24-epibrassinolide enhanced the resistance of cucumber plants against P. melonis. Furthermore, we found that both knockout and overexpression of the BR biosynthesis gene CYP85A1 reduced the endogenous GA3 content compared with that of wild-type plants under the condition of inoculation with P. melonis, and the enhancement of disease resistance conferred by BR was inhibited in plants with silencing of the GA biosynthetic gene GA20ox1 or KAO. Together, these findings suggest that GA homeostasis is an essential factor mediating BRs-induced disease resistance. Moreover, BZR6, a key regulator of BR signaling, was found to physically interact with GA20ox1, thereby suppressing its transcription. Silencing of BZR6 promoted endogenous GA biosynthesis and compromised GA-mediated resistance. These findings reveal multifaceted crosstalk between BR and GA in response to pathogen infection, which can provide a new approach for genetically controlling P. melonis damage in cucumber production.
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Brasinoesteroides , Cucumis sativus , Resistencia a la Enfermedad , Giberelinas , Phytophthora , Enfermedades de las Plantas , Phytophthora/fisiología , Brasinoesteroides/metabolismo , Cucumis sativus/microbiología , Cucumis sativus/genética , Cucumis sativus/metabolismo , Cucumis sativus/parasitología , Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/parasitología , Enfermedades de las Plantas/inmunología , Giberelinas/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Reguladores del Crecimiento de las Plantas/metabolismo , Transducción de SeñalRESUMEN
BRI1-EMS Suppressor 1 (BES1) and Brassinazole resistant 1 (BZR1) are two highly similar master transcription factors of the brassinosteroid (BR) signaling pathway that regulate a variety of plant growth and development processes as well as stress responses. Previous genetic and biochemical analyses have established a complex regulatory network to control the two transcription factors. This network includes coordination with other transcription factors and interactors, multiple post-translational modifications (PTMs), and differential subcellular localizations. In this review, we systematically detail the functions and regulatory mechanisms of various PTMs: phosphorylation/dephosphorylation, ubiquitination/deubiquitination, SUMOylation/deSUMOylation, oxidation/reduction, in regulating the subcellular localization, protein stability, and the transcriptional activity of BES1/BZR1. We also discuss the current knowledge about the BES1/BZR1-interactors mediating the dynamic nucleocytoplasmic shuttling of BES1 and BZR1.
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One of the main signal transduction pathways that modulate plant growth and stress responses, including drought, is the action of phytohormones. Recent advances in omics approaches have facilitated the exploration of plant genomes. However, the molecular mechanisms underlying the response in the crown of barley, which plays an essential role in plant performance under stress conditions and regeneration after stress treatment, remain largely unclear. The objective of the present study was the elucidation of drought-induced molecular reactions in the crowns of different barley phytohormone mutants. We verified the hypothesis that defects of gibberellins, brassinosteroids, and strigolactones action affect the transcriptomic, proteomic, and hormonal response of barley crown to the transitory drought influencing plant development under stress. Moreover, we assumed that due to the strong connection between strigolactones and branching the hvdwarf14.d mutant, with dysfunctional receptor of strigolactones, manifests the most abundant alternations in crowns and phenotype under drought. Finally, we expected to identify components underlying the core response to drought which are independent of the genetic background. Large-scale analyses were conducted using gibberellins-biosynthesis, brassinosteroids-signaling, and strigolactones-signaling mutants, as well as reference genotypes. Detailed phenotypic evaluation was also conducted. The obtained results clearly demonstrated that hormonal disorders caused by mutations in the HvGA20ox2, HvBRI1, and HvD14 genes affected the multifaceted reaction of crowns to drought, although the expression of these genes was not induced by stress. The study further detected not only genes and proteins that were involved in the drought response and reacted specifically in mutants compared to the reaction of reference genotypes and vice versa, but also the candidates that may underlie the genotype-universal stress response. Furthermore, candidate genes involved in phytohormonal interactions during the drought response were identified. We also found that the interplay between hormones, especially gibberellins and auxins, as well as strigolactones and cytokinins may be associated with the regulation of branching in crowns exposed to drought. Overall, the present study provides novel insights into the molecular drought-induced responses that occur in barley crowns.
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Sequías , Hordeum , Mutación , Reguladores del Crecimiento de las Plantas , Hordeum/genética , Hordeum/metabolismo , Hordeum/crecimiento & desarrollo , Reguladores del Crecimiento de las Plantas/metabolismo , Mutación/genética , Giberelinas/metabolismo , Regulación de la Expresión Génica de las Plantas , Brasinoesteroides/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estrés Fisiológico/genética , Lactonas/metabolismoRESUMEN
Brassinosteroids (BRs) play a vital role in plant growth and stress response, operating through a well-defined signaling pathway. Yet, the export of BRs through plasma membranes poses significant challenges. Ying et al. recently identified the essential role of the ATPase activity of ABCB19 (Arabidopsis thaliana ATP-binding cassette transporter) in BR transport.
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BACKGROUND: Brassinosteroids (BRs) are a class of phytohormones that regulate a wide range of developmental processes in plants. BR-associated mutants display impaired growth and response to developmental and environmental stimuli. RESULTS: Here, we found that a BR-deficient mutant det2-1 displayed abnormal root gravitropic growth in Arabidopsis, which was not present in other BR mutants. To further elucidate the role of DET2 in gravity, we performed transcriptome sequencing and analysis of det2-1 and bri1-116, bri1 null mutant allele. Expression levels of auxin, gibberellin, cytokinin, and other related genes in the two mutants of det2-1 and bri1-116 were basically the same. However, we only found that a large number of JAZ (JASMONATE ZIM-domain) genes and jasmonate synthesis-related genes were upregulated in det2-1 mutant, suggesting increased levels of endogenous JA. CONCLUSIONS: Our results also suggested that DET2 not only plays a role in BR synthesis but may also be involved in JA regulation. Our study provides a new insight into the molecular mechanism of BRs on the root gravitropism.