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1.
Int J Mol Sci ; 22(16)2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34445728

RESUMO

Phytopathogens, such as biotrophs, hemibiotrophs and necrotrophs, pose serious stress on the development of their host plants, compromising their yields. Plants are in constant interaction with such phytopathogens and hence are vulnerable to their attack. In order to counter these attacks, plants need to develop immunity against them. Consequently, plants have developed strategies of recognizing and countering pathogenesis through pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Pathogen perception and surveillance is mediated through receptor proteins that trigger signal transduction, initiated in the cytoplasm or at the plasma membrane (PM) surfaces. Plant hosts possess microbe-associated molecular patterns (P/MAMPs), which trigger a complex set of mechanisms through the pattern recognition receptors (PRRs) and resistance (R) genes. These interactions lead to the stimulation of cytoplasmic kinases by many phosphorylating proteins that may also be transcription factors. Furthermore, phytohormones, such as salicylic acid, jasmonic acid and ethylene, are also effective in triggering defense responses. Closure of stomata, limiting the transfer of nutrients through apoplast and symplastic movements, production of antimicrobial compounds, programmed cell death (PCD) are some of the primary defense-related mechanisms. The current article highlights the molecular processes involved in plant innate immunity (PII) and discusses the most recent and plausible scientific interventions that could be useful in augmenting PII.


Assuntos
Interações Hospedeiro-Patógeno , Imunidade Inata , Plantas/imunologia , Transdução de Sinais , Cromatina/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Plantas/metabolismo
2.
Int J Mol Sci ; 22(16)2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34445746

RESUMO

Nitrogen is an important factor limiting the growth and yield of rice. However, the excessive application of nitrogen will lead to water eutrophication and economic costs. To create rice varieties with high nitrogen use efficiency (NUE) has always been an arduous task in rice breeding. The processes for improving NUE include nitrogen uptake, nitrogen transport from root to shoot, nitrogen assimilation, and nitrogen redistribution, with each step being indispensable to the improvement of NUE. Here, we summarize the effects of absorption, transport, and metabolism of nitrate, ammonium, and amino acids on NUE, as well as the role of hormones in improving rice NUE. Our discussion provide insight for further research in the future.


Assuntos
Nitrogênio/metabolismo , Oryza/genética , Oryza/metabolismo , Aminoácidos/metabolismo , Compostos de Amônio/metabolismo , Redes Reguladoras de Genes , Variação Genética , Nitratos/metabolismo , Reguladores de Crescimento de Plantas/metabolismo
3.
Int J Mol Sci ; 22(16)2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34445260

RESUMO

De novo shoot organogenesis (DNSO) is a procedure commonly used for the in vitro regeneration of shoots from a variety of plant tissues. Shoot regeneration occurs on nutrient media supplemented with the plant hormones cytokinin (CK) and auxin, which play essential roles in this process, and genes involved in their signaling cascades act as master regulators of the different phases of shoot regeneration. In the last 20 years, the genetic regulation of DNSO has been characterized in detail. However, as of today, the CK and auxin signaling events associated with shoot regeneration are often interpreted as a consequence of these hormones simply being present in the regeneration media, whereas the roles for their prior uptake and transport into the cultivated plant tissues are generally overlooked. Additionally, sucrose, commonly added to the regeneration media as a carbon source, plays a signaling role and has been recently shown to interact with CK and auxin and to affect the efficiency of shoot regeneration. In this review, we provide an integrative interpretation of the roles for CK and auxin in the process of DNSO, adding emphasis on their uptake from the regeneration media and their interaction with sucrose present in the media to their complex signaling outputs that mediate shoot regeneration.


Assuntos
Citocininas/metabolismo , Ácidos Indolacéticos/metabolismo , Organogênese Vegetal , Reguladores de Crescimento de Plantas/metabolismo , Brotos de Planta/metabolismo , Brotos de Planta/citologia
4.
Int J Mol Sci ; 22(16)2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34445272

RESUMO

As sessile organisms, plants must tolerate various environmental stresses. Plant hormones play vital roles in plant responses to biotic and abiotic stresses. Among these hormones, jasmonic acid (JA) and its precursors and derivatives (jasmonates, JAs) play important roles in the mediation of plant responses and defenses to biotic and abiotic stresses and have received extensive research attention. Although some reviews of JAs are available, this review focuses on JAs in the regulation of plant stress responses, as well as JA synthesis, metabolism, and signaling pathways. We summarize recent progress in clarifying the functions and mechanisms of JAs in plant responses to abiotic stresses (drought, cold, salt, heat, and heavy metal toxicity) and biotic stresses (pathogen, insect, and herbivore). Meanwhile, the crosstalk of JA with various other plant hormones regulates the balance between plant growth and defense. Therefore, we review the crosstalk of JAs with other phytohormones, including auxin, gibberellic acid, salicylic acid, brassinosteroid, ethylene, and abscisic acid. Finally, we discuss current issues and future opportunities in research into JAs in plant stress responses.


Assuntos
Ciclopentanos/metabolismo , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Plantas/metabolismo , Estresse Fisiológico
5.
Plant Mol Biol ; 107(1-2): 1-20, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34398355

RESUMO

KEY MESSAGE: Analyses of the function of Arabidopsis Calmodulin7 (CAM7) in concert with multiple regulatory proteins involved in various signal transduction processes. Calmodulin (CaM) plays various regulatory roles in multiple signaling pathways in eukaryotes. Arabidopsis CALMODULIN 7 (CAM7) is a unique member of the CAM family that works as a transcription factor in light signaling pathways. CAM7 works in concert with CONSTITUTIVE PHOTOMORPHOGENIC 1 and ELONGATED HYPOCOTYL 5, and plays an important role in seedling development. Further, it is involved in the regulation of the activity of various Ca2+-gated channels such as cyclic nucleotide gated channel 6 (CNGC6), CNGC14 and auto-inhibited Ca2+ ATPase 8. Recent studies further indicate that CAM7 is also an integral part of multiple signaling pathways including hormone, immunity and stress. Here, we review the recent advances in understanding the multifaceted role of CAM7. We highlight the open-ended questions, and also discuss the diverse aspects of CAM7 characterization that need to be addressed for comprehensive understanding of its cellular functions.


Assuntos
Calmodulina/metabolismo , Desenvolvimento Vegetal , Estresse Fisiológico , Sequência de Aminoácidos , Apoptose , Calmodulina/química , Morfogênese , Reguladores de Crescimento de Plantas/metabolismo
6.
Biomolecules ; 11(8)2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34439819

RESUMO

With the introduction of the new auxinic herbicide halauxifen-methyl into the oilseed rape (Brassica napus) market, there is a need to understand how this new molecule interacts with indigenous plant hormones (e.g., IAA) in terms of crop response. The aim of this study was to investigate the molecular background by using different growth conditions under which three different auxinic herbicides were administered. These were halauxifen-methyl (Hal), alone and together with aminopyralid (AP) as well as picloram (Pic). Three different hormone classes were determined, free and conjugated indole-3-acetic acid (IAA), aminocyclopropane carboxylic acid (ACC) as a precursor for ethylene, and abscisic acid (ABA) at two different temperatures and growth stages as well as over time (2-168 h after treatment). At 15 °C growth temperature, the effect was more pronounced than at 9 °C, and generally, the younger leaves independent of the developmental stage showed a larger effect on the alterations of hormones. IAA and ACC showed reproducible alterations after auxinic herbicide treatments over time, while ABA did not. Finally, a transcriptome analysis after treatment with two auxinic herbicides, Hal and Pic, showed different expression patterns. Hal treatment leads to the upregulation of auxin and hormone responses at 48 h and 96 h. Pic treatment induced the hormone/auxin response already after 2 h, and this continued for the other time points. The more detailed analysis of the auxin response in the datasets indicate a role for GH3 genes and genes encoding auxin efflux proteins. The upregulation of the GH3 genes correlates with the increase in conjugated IAA at the same time points and treatments. Also, genes for were found that confirm the upregulation of the ethylene pathway.


Assuntos
Ácido Abscísico/farmacologia , Aminoácidos Cíclicos/farmacologia , Brassica napus/efeitos dos fármacos , Herbicidas/farmacologia , Ácidos Indolacéticos/farmacologia , Reguladores de Crescimento de Plantas/farmacologia , Ácido Abscísico/metabolismo , Aminoácidos Cíclicos/metabolismo , Brassica napus/genética , Brassica napus/metabolismo , Ácidos Carboxílicos/farmacologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Ácidos Indolacéticos/metabolismo , Anotação de Sequência Molecular , Picloram/farmacologia , Reguladores de Crescimento de Plantas/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Piridinas/farmacologia , Temperatura , Transcriptoma
7.
Biomolecules ; 11(8)2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34439825

RESUMO

Among abiotic stressors, drought and salinity seriously affect crop growth worldwide. In plants, research has aimed to increase stress-responsive protein synthesis upstream or downstream of the various transcription factors (TFs) that alleviate drought and salinity stress. TFs play diverse roles in controlling gene expression in plants, which is necessary to regulate biological processes, such as development and environmental stress responses. In general, plant responses to different stress conditions may be either abscisic acid (ABA)-dependent or ABA-independent. A detailed understanding of how TF pathways and ABA interact to cause stress responses is essential to improve tolerance to drought and salinity stress. Despite previous progress, more active approaches based on TFs are the current focus. Therefore, the present review emphasizes the recent advancements in complex cascades of gene expression during drought and salinity responses, especially identifying the specificity and crosstalk in ABA-dependent and -independent signaling pathways. This review also highlights the transcriptional regulation of gene expression governed by various key TF pathways, including AP2/ERF, bHLH, bZIP, DREB, GATA, HD-Zip, Homeo-box, MADS-box, MYB, NAC, Tri-helix, WHIRLY, WOX, WRKY, YABBY, and zinc finger, operating in ABA-dependent and -independent signaling pathways.


Assuntos
Ácido Abscísico/metabolismo , Adaptação Fisiológica/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Plantas/genética , Fatores de Transcrição/genética , Secas , Reguladores de Crescimento de Plantas/metabolismo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/classificação , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plantas/metabolismo , Plantas Geneticamente Modificadas , Espécies Reativas de Oxigênio/metabolismo , Salinidade , Transdução de Sinais , Estresse Fisiológico/genética , Fatores de Transcrição/classificação , Fatores de Transcrição/metabolismo
8.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445112

RESUMO

Brassinosteroids (BRs) are steroid phytohormones that are known to regulate plant growth and nutrient uptake and distribution. However, how BRs regulate nutrient uptake and balance in legume species is not fully understood. Here, we show that optimal BR levels are required for soybean (Glycine max L.) seedling growth, as treatments with both 24-epicastasterone (24-epiCS) and the BR biosynthesis inhibitor propiconazole (PPZ) inhibit root growth, including primary root elongation and lateral root formation and elongation. Specifically, 24-epiCS and PPZ reduced the total phosphorus and potassium levels in the shoot and affected several minor nutrients, such as magnesium, iron, manganese, and molybdenum. A genome-wide transcriptome analysis identified 3774 and 4273 differentially expressed genes in the root tip after brassinolide and PPZ treatments, respectively. The gene ontology (GO) analysis suggested that genes related to "DNA-replication", "microtubule-based movement", and "plant-type cell wall organization" were highly responsive to the brassinolide and PPZ treatments. Furthermore, consistent with the effects on the nutrient concentrations, corresponding mineral transporters were found to be regulated by BR levels, including the GmPHT1s, GmKTs, GmVIT2, GmZIPs, and GmMOT1 genes. Our study demonstrates that optimal BR levels are important for growth and mineral nutrient homeostasis in soybean seedlings.


Assuntos
Brassinosteroides/metabolismo , Homeostase/fisiologia , Minerais/metabolismo , Nutrientes/metabolismo , Soja/crescimento & desenvolvimento , Soja/metabolismo , Colestanóis/metabolismo , Fabaceae/metabolismo , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/fisiologia , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plântula/metabolismo , Esteroides Heterocíclicos/metabolismo
9.
BMC Plant Biol ; 21(1): 361, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34364372

RESUMO

BACKGROUND: Priming of seed prior chilling is regarded as one of the methods to promote seeds germination, whole plant growth, and yield components. The application of biostimulants was reported as beneficial for protecting many plants from biotic or abiotic stresses. Their value was as important to be involved in improving the growth parameters of plants. Also, they were practiced in the regulation of various metabolic pathways to enhance acclimation and tolerance in coriander against chilling stress. To our knowledge, little is deciphered about the molecular mechanisms underpinning the ameliorative impact of biostimulants in the context of understanding the link and overlap between improved morphological characters, induced metabolic processes, and upregulated gene expression. In this study, the ameliorative effect(s) of potassium silicate, HA, and gamma radiation on acclimation of coriander to tolerate chilling stress was evaluated by integrating the data of growth, yield, physiological and molecular aspects. RESULTS: Plant growth, yield components, and metabolic activities were generally diminished in chilling-stressed coriander plants. On the other hand, levels of ABA and soluble sugars were increased. Alleviation treatment by humic acid, followed by silicate and gamma irradiation, has notably promoted plant growth parameters and yield components in chilling-stressed coriander plants. This improvement was concomitant with a significant increase in phytohormones, photosynthetic pigments, carbohydrate contents, antioxidants defense system, and induction of large subunit of RuBisCO enzyme production. The assembly of Toc complex subunits was maintained, and even their expression was stimulated (especially Toc75 and Toc 34) upon alleviation of the chilling stress by applied biostimulators. Collectively, humic acid was the best the element to alleviate the adverse effects of chilling stress on growth and productivity of coriander. CONCLUSIONS: It could be suggested that the inducing effect of the pretreatments on hormonal balance triggered an increase in IAA + GA3/ABA hormonal ratio. This ratio could be linked and engaged with the protection of cellular metabolic activities from chilling injury against the whole plant life cycle. Therefore, it was speculated that seed priming in humic acid is a powerful technique that can benefit the chilled along with non-chilled plants and sustain the economic importance of coriander plant productivity.


Assuntos
Resposta ao Choque Frio/fisiologia , Coriandrum/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/farmacologia , Sementes/crescimento & desenvolvimento , Aclimatação , Antioxidantes/metabolismo , Metabolismo dos Carboidratos , Carboidratos/análise , Proteínas de Cloroplastos/metabolismo , Resposta ao Choque Frio/efeitos dos fármacos , Resposta ao Choque Frio/efeitos da radiação , Coriandrum/efeitos dos fármacos , Coriandrum/efeitos da radiação , Enzimas/metabolismo , Raios gama , Substâncias Húmicas , Peroxidação de Lipídeos , Pigmentos Biológicos/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Compostos de Potássio/química , Compostos de Potássio/farmacologia , Sementes/efeitos dos fármacos , Sementes/efeitos da radiação
10.
Int J Mol Sci ; 22(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34445546

RESUMO

Temperature stress is one of the major abiotic stresses that adversely affect agricultural productivity worldwide. Temperatures beyond a plant's physiological optimum can trigger significant physiological and biochemical perturbations, reducing plant growth and tolerance to stress. Improving a plant's tolerance to these temperature fluctuations requires a deep understanding of its responses to environmental change. To adapt to temperature fluctuations, plants tailor their acclimatory signal transduction events, and specifically, cellular redox state, that are governed by plant hormones, reactive oxygen species (ROS) regulatory systems, and other molecular components. The role of ROS in plants as important signaling molecules during stress acclimation has recently been established. Here, hormone-triggered ROS produced by NADPH oxidases, feedback regulation, and integrated signaling events during temperature stress activate stress-response pathways and induce acclimation or defense mechanisms. At the other extreme, excess ROS accumulation, following temperature-induced oxidative stress, can have negative consequences on plant growth and stress acclimation. The excessive ROS is regulated by the ROS scavenging system, which subsequently promotes plant tolerance. All these signaling events, including crosstalk between hormones and ROS, modify the plant's transcriptomic, metabolomic, and biochemical states and promote plant acclimation, tolerance, and survival. Here, we provide a comprehensive review of the ROS, hormones, and their joint role in shaping a plant's responses to high and low temperatures, and we conclude by outlining hormone/ROS-regulated plant responsive strategies for developing stress-tolerant crops to combat temperature changes.


Assuntos
Adaptação Fisiológica , Reguladores de Crescimento de Plantas/metabolismo , Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Temperatura
11.
Nat Commun ; 12(1): 4804, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34376671

RESUMO

Plants respond to warm temperature by increased elongation growth of organs to enhance cooling capacity. Phytohormones, such as auxin and brassinosteroids, regulate this growth process. However, our view on the players involved in warm temperature-mediated growth remains fragmentary. Here, we show that warm temperature leads to an increased expression of JOXs and ST2A, genes controlling jasmonate catabolism. This leads to an elevated 12HSO4-JA level and consequently to a reduced level of bioactive jasmonates. Ultimately this results in more JAZ proteins, which facilitates plant growth under warm temperature conditions. Taken together, understanding the conserved role of jasmonate signalling during thermomorphogenesis contributes to ensuring food security under a changing climate.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Ciclopentanos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Oxilipinas/metabolismo , Temperatura , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Plantas Geneticamente Modificadas , Transdução de Sinais
12.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34360958

RESUMO

Semi-dwarfism is a main agronomic trait in crop breeding. In this study, we performed genome-wide association study (GWAS) and identified a new quantitative trait nucleotide (QTN) for rice shoot length. The peak QTN (C/T) was located in the first coding region of a group III WRKY transcription factor OsWRKY21 (LOC_Os01g60640). Interestingly, further haplotype analysis showed that C/T difference only existed in the indica group but not in the japonica group, resulting in significant differences in plant height among the different indica rice varieties. OsWRKY21 was expressed in embryo, radicle, shoots, leaves, and stems. Most notably, overexpressing OsWRKY21 resulted in the semi-dwarf phenotype, early heading date and short internodes compared to the wild type, while the knockout mutant plants by CRISPR/Cas9 technology yielded the opposite. The overexpressing lines exhibited the decreased length of the cells near sclerenchyma epidermis, accompanied with the lower levels of indole-3-acetic acid (IAA) and gibberellin 3 (GA3), but increased levels of the abscisic acid (ABA) and salicylic acid (SA) in the internodes at heading stage. Moreover, the semi-dwarf phenotype could be fully rescued by exogenous GA3 application at seedling stage. The RNA-seq and qRT-PCR analysis confirmed the differential expression levels of genes in development and the stress responses in rice, including GA metabolism (GA20ox2, GA2ox6, and YABY1) and cell wall biosynthesis (CesA4, 7, and 9) and regulation (MYB103L). These data suggest the essential role of OsWRKY21 in regulation of internode elongation and plant height in rice.


Assuntos
Oryza/genética , Proteínas de Plantas/genética , Caules de Planta/crescimento & desenvolvimento , Locos de Características Quantitativas , Fatores de Transcrição/genética , Estudo de Associação Genômica Ampla , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Melhoramento Vegetal , Reguladores de Crescimento de Plantas/metabolismo , Caules de Planta/genética , Característica Quantitativa Herdável
13.
BMC Plant Biol ; 21(1): 365, 2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34380415

RESUMO

BACKGROUND: Kiwifruit (Actinidia Lindl.) is considered an important fruit species worldwide. Due to its temperate origin, this species is highly vulnerable to freezing injury while under low-temperature stress. To obtain further knowledge of the mechanism underlying freezing tolerance, we carried out a hybrid transcriptome analysis of two A. arguta (Actinidi arguta) genotypes, KL and RB, whose freezing tolerance is high and low, respectively. Both genotypes were subjected to - 25 °C for 0 h, 1 h, and 4 h. RESULTS: SMRT (single-molecule real-time) RNA-seq data were assembled using the de novo method, producing 24,306 unigenes with an N50 value of 1834 bp. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of DEGs showed that they were involved in the 'starch and sucrose metabolism', the 'mitogen-activated protein kinase (MAPK) signaling pathway', the 'phosphatidylinositol signaling system', the 'inositol phosphate metabolism', and the 'plant hormone signal transduction'. In particular, for 'starch and sucrose metabolism', we identified 3 key genes involved in cellulose degradation, trehalose synthesis, and starch degradation processes. Moreover, the activities of beta-GC (beta-glucosidase), TPS (trehalose-6-phosphate synthase), and BAM (beta-amylase), encoded by the abovementioned 3 key genes, were enhanced by cold stress. Three transcription factors (TFs) belonging to the AP2/ERF, bHLH (basic helix-loop-helix), and MYB families were involved in the low-temperature response. Furthermore, weighted gene coexpression network analysis (WGCNA) indicated that beta-GC, TPS5, and BAM3.1 were the key genes involved in the cold response and were highly coexpressed together with the CBF3, MYC2, and MYB44 genes. CONCLUSIONS: Cold stress led various changes in kiwifruit, the 'phosphatidylinositol signaling system', 'inositol phosphate metabolism', 'MAPK signaling pathway', 'plant hormone signal transduction', and 'starch and sucrose metabolism' processes were significantly affected by low temperature. Moreover, starch and sucrose metabolism may be the key pathway for tolerant kiwifruit to resist low temperature damages. These results increase our understanding of the complex mechanisms involved in the freezing tolerance of kiwifruit under cold stress and reveal a series of candidate genes for use in breeding new cultivars with enhanced freezing tolerance.


Assuntos
Aclimatação/genética , Actinidia/genética , Actinidia/fisiologia , Congelamento , Regulação da Expressão Gênica de Plantas , Frutas/genética , Frutas/fisiologia , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Sistema de Sinalização das MAP Quinases , Anotação de Sequência Molecular , Fosfatidilinositóis/metabolismo , Melhoramento Vegetal , Reguladores de Crescimento de Plantas/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Amido/metabolismo , Sacarose/metabolismo
14.
Nat Plants ; 7(9): 1229-1238, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34282287

RESUMO

The membrane potential reflects the difference between cytoplasmic and apoplastic electrical potentials and is essential for cellular operation. The application of the phytohormone auxin (3-indoleacetic acid (IAA)) causes instantaneous membrane depolarization in various cell types1-6, making depolarization a hallmark of IAA-induced rapid responses. In root hairs, depolarization requires functional IAA transport and TIR1-AFB signalling5, but its physiological importance is not understood. Specifically in roots, auxin triggers rapid growth inhibition7-9 (RGI), a process required for gravitropic bending. RGI is initiated by the TIR1-AFB co-receptors, with the AFB1 paralogue playing a crucial role10,11. The nature of the underlying rapid signalling is unknown, as well as the molecular machinery executing it. Even though the growth and depolarization responses to auxin show remarkable similarities, the importance of membrane depolarization for root growth inhibition and gravitropism is unclear. Here, by combining the DISBAC2(3) voltage sensor with microfluidics and vertical-stage microscopy, we show that rapid auxin-induced membrane depolarization tightly correlates with RGI. Rapid depolarization and RGI require the AFB1 auxin co-receptor. Finally, AFB1 is essential for the rapid formation of the membrane depolarization gradient across the gravistimulated root. These results clarify the role of AFB1 as the central receptor for rapid auxin responses.


Assuntos
Proteínas de Arabidopsis/metabolismo , Membrana Celular/efeitos dos fármacos , Gravitropismo/efeitos dos fármacos , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas , Variação Genética , Genótipo , Potenciais da Membrana/fisiologia , Plantas Geneticamente Modificadas/metabolismo
15.
Nat Plants ; 7(8): 1108-1118, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34226689

RESUMO

Complex antagonistic interactions between abscisic acid (ABA) and brassinosteroid (BR) signalling pathways have been widely documented. However, whether or how ABA interacts synergistically with BR in plants remains to be elucidated. Here, we report that low, but not high, concentration of ABA increases lamina joint inclination of rice seedling, which requires functional BR biosynthesis and signalling. Transcriptome analyses confirm that about 60% of low-concentration ABA early response genes can be regulated by BR in the same directions. ABA activates BR signal in a fast, limited and short-term manner and the BR-biosynthesis regulatory gene, OsGSR1, plays a key role during this process, whose expression is induced slightly by ABA through transcriptional factor ABI3. Moreover, the early short-term BR signal activation is also important for ABA-mediated salt stress tolerance. Intriguingly, the process and effect of short-term BR signal activation were covered by high concentration of ABA, implying adaptive mechanisms existed in plants to cope with varying degrees of stress.


Assuntos
Ácido Abscísico/metabolismo , Adaptação Fisiológica/genética , Brassinosteroides/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/genética , Reguladores de Crescimento de Plantas/metabolismo , Tolerância ao Sal/efeitos dos fármacos , Tolerância ao Sal/genética , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Variação Genética , Genótipo , Desenvolvimento Vegetal/efeitos dos fármacos , Desenvolvimento Vegetal/genética , Plântula/genética , Plântula/crescimento & desenvolvimento , Transdução de Sinais , Estresse Fisiológico , Fatores de Transcrição
16.
Int J Mol Sci ; 22(14)2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34299234

RESUMO

Brassinosteroids (BRs) are known to be essential regulators for wood formation in herbaceous plants and poplar, but their roles in secondary growth and xylem development are still not well-defined, especially in pines. Here, we treated Pinus massoniana seedlings with different concentrations of exogenous BRs, and assayed the effects on plant growth, xylem development, endogenous phytohormone contents and gene expression within stems. Application of exogenous BR resulted in improving development of xylem more than phloem, and promoting xylem development in a dosage-dependent manner in a certain concentration rage. Endogenous hormone determination showed that BR may interact with other phytohormones in regulating xylem development. RNA-seq analysis revealed that some conventional phenylpropanoid biosynthesis- or lignin synthesis-related genes were downregulated, but the lignin content was elevated, suggesting that new lignin synthesis pathways or other cell wall components should be activated by BR treatment in P. massoniana. The results presented here reveal the foundational role of BRs in regulating plant secondary growth, and provide the basis for understanding molecular mechanisms of xylem development in P. massoniana.


Assuntos
Brassinosteroides/farmacologia , Pinus/metabolismo , Xilema/metabolismo , Brassinosteroides/metabolismo , Parede Celular/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Lignina/metabolismo , Floema/efeitos dos fármacos , Floema/metabolismo , Pinus/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Proteínas de Plantas/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Madeira/genética , Xilema/efeitos dos fármacos , Xilema/crescimento & desenvolvimento
17.
Int J Mol Sci ; 22(13)2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34201662

RESUMO

Gene expression and phytohormone contents were measured in response to elevating ascorbate in the absence of other confounding stimuli such as high light and abiotic stresses. Young Arabidopsis plants were treated with 25 mM solutions of l-galactose pathway intermediates l-galactose (l-gal) or l-galactono-1,4-lactone (l-galL), as well as L-ascorbic acid (AsA), with 25 mM glucose used as control. Feeding increased rosette AsA 2- to 4-fold but there was little change in AsA biosynthetic gene transcripts. Of the ascorbate recycling genes, only Dehydroascorbate reductase 1 expression was increased. Some known regulatory genes displayed increased expression and included ANAC019, ANAC072, ATHB12, ZAT10 and ZAT12. Investigation of the ANAC019/ANAC072/ATHB12 gene regulatory network revealed a high proportion of ABA regulated genes. Measurement of a subset of jasmonate, ABA, auxin (IAA) and salicylic acid compounds revealed consistent increases in ABA (up to 4.2-fold) and phaseic acid (PA; up to 5-fold), and less consistently certain jasmonates, IAA, but no change in salicylic acid levels. Increased ABA is likely due to increased transcripts for the ABA biosynthetic gene NCED3. There were also smaller increases in transcripts for transcription factors ATHB7, ERD1, and ABF3. These results provide insights into how increasing AsA content can mediate increased abiotic stress tolerance.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/fisiologia , Ácido Ascórbico/metabolismo , Glutationa Transferase/genética , Reguladores de Crescimento de Plantas/metabolismo , Estresse Fisiológico/fisiologia , Ácido Abscísico/metabolismo , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/metabolismo , Ascorbato Oxidase/genética , Ascorbato Oxidase/metabolismo , Ácido Ascórbico/genética , Ciclopentanos/metabolismo , Galactose/farmacologia , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Glutationa Transferase/metabolismo , Ácidos Hexurônicos/metabolismo , Ácidos Indolacéticos/metabolismo , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/genética , Sesquiterpenos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Int J Mol Sci ; 22(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34281157

RESUMO

Post-translational modifications play a fundamental role in regulating protein function and stability. In particular, protein ubiquitylation is a multifaceted modification involved in numerous aspects of plant biology. Landmark studies connected the ATP-dependent ubiquitylation of substrates to their degradation by the 26S proteasome; however, nonproteolytic functions of the ubiquitin (Ub) code are also crucial to regulate protein interactions, activity, and localization. Regarding proteolytic functions of Ub, Lys-48-linked branched chains are the most common chain type for proteasomal degradation, whereas promotion of endocytosis and vacuolar degradation is triggered through monoubiquitylation or Lys63-linked chains introduced in integral or peripheral plasma membrane proteins. Hormone signaling relies on regulated protein turnover, and specifically the half-life of ABA signaling components is regulated both through the ubiquitin-26S proteasome system and the endocytic/vacuolar degradation pathway. E3 Ub ligases have been reported that target different ABA signaling core components, i.e., ABA receptors, PP2Cs, SnRK2s, and ABFs/ABI5 transcription factors. In this review, we focused specifically on the ubiquitylation of ABA receptors and PP2C coreceptors, as well as other post-translational modifications of ABA receptors (nitration and phosphorylation) that result in their ubiquitination and degradation.


Assuntos
Ácido Abscísico/metabolismo , Proteína Fosfatase 2C/metabolismo , Estresse Fisiológico/fisiologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Fosforilação , Reguladores de Crescimento de Plantas/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Processamento de Proteína Pós-Traducional , Transdução de Sinais , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
19.
Int J Mol Sci ; 22(13)2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34281289

RESUMO

Several recent studies have shown that citric acid/citrate (CA) can confer abiotic stress tolerance to plants. Exogenous CA application leads to improved growth and yield in crop plants under various abiotic stress conditions. Improved physiological outcomes are associated with higher photosynthetic rates, reduced reactive oxygen species, and better osmoregulation. Application of CA also induces antioxidant defense systems, promotes increased chlorophyll content, and affects secondary metabolism to limit plant growth restrictions under stress. In particular, CA has a major impact on relieving heavy metal stress by promoting precipitation, chelation, and sequestration of metal ions. This review summarizes the mechanisms that mediate CA-regulated changes in plants, primarily CA's involvement in the control of physiological and molecular processes in plants under abiotic stress conditions. We also review genetic engineering strategies for CA-mediated abiotic stress tolerance. Finally, we propose a model to explain how CA's position in complex metabolic networks involving the biosynthesis of phytohormones, amino acids, signaling molecules, and other secondary metabolites could explain some of its abiotic stress-ameliorating properties. This review summarizes our current understanding of CA-mediated abiotic stress tolerance and highlights areas where additional research is needed.


Assuntos
Ácido Cítrico/metabolismo , Ácido Cítrico/farmacologia , Plantas/efeitos dos fármacos , Plantas/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Adaptação Fisiológica/efeitos dos fármacos , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Secas , Engenharia Genética , Resposta ao Choque Térmico/efeitos dos fármacos , Inativação Metabólica , Metais Pesados/farmacocinética , Metais Pesados/toxicidade , Modelos Biológicos , Desenvolvimento Vegetal/efeitos dos fármacos , Reguladores de Crescimento de Plantas/metabolismo , Plantas/genética , Espécies Reativas de Oxigênio/metabolismo , Estresse Salino/efeitos dos fármacos , Estresse Fisiológico/genética
20.
BMC Plant Biol ; 21(1): 331, 2021 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-34246235

RESUMO

BACKGROUND: As damage to the ecological environment continues to increase amid unreasonable amounts of irrigation, soil salinization has become a major challenge to agricultural development. Melatonin (MT) is a pleiotropic signal molecule and indole hormone, which alleviates the damage of abiotic stress to plants. MT has been confirmed to eliminate reactive oxygen species (ROS) by improving the antioxidant system and reducing oxidative damage under adversity. However, the mechanism by which exogenous MT mediates salt tolerance by regulating the photosynthetic capacity and ion balance of cotton seedlings still remains unknown. In this study, the regulatory effects of MT on the photosynthetic system, osmotic modulators, chloroplast, and anatomical structure of cotton seedlings were determined under 0-500 µM MT treatments with salt stress induced by treatment with 150 mM NaCl. RESULTS: Salt stress reduces the chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, PSII photochemical efficiency, PSII actual photochemical quantum yield, the apparent electron transfer efficiency, stomata opening, and biomass. In addition, it increases non-photochemical quenching. All of these responses were effectively alleviated by exogenous treatment with MT. Exogenous MT reduces oxidative damage and lipid peroxidation by reducing salt-induced ROS and protects the plasma membrane from oxidative toxicity. MT also reduces the osmotic pressure by reducing the salt-induced accumulation of Na+ and increasing the contents of K+ and proline. Exogenous MT can facilitate stomatal opening and protect the integrity of cotton chloroplast grana lamella structure and mitochondria under salt stress, protect the photosynthetic system of plants, and improve their biomass. An anatomical analysis of leaves and stems showed that MT can improve xylem and phloem and other properties and aides in the transportation of water, inorganic salts, and organic substances. Therefore, the application of MT attenuates salt-induced stress damage to plants. Treatment with exogenous MT positively increased the salt tolerance of cotton seedlings by improving their photosynthetic capacity, stomatal characteristics, ion balance, osmotic substance biosynthetic pathways, and chloroplast and anatomical structures (xylem vessels and phloem vessels). CONCLUSIONS: Our study attributes help to protect the structural stability of photosynthetic organs and increase the amount of material accumulation, thereby reducing salt-induced secondary stress. The mechanisms of MT-induced plant tolerance to salt stress provide a theoretical basis for the use of MT to alleviate salt stress caused by unreasonable irrigation, fertilization, and climate change.


Assuntos
Gossypium/metabolismo , Melatonina/metabolismo , Fotossíntese/efeitos dos fármacos , Reguladores de Crescimento de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Estresse Salino/efeitos dos fármacos , Tolerância ao Sal/efeitos dos fármacos , Produtos Agrícolas/metabolismo
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