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1.
Development ; 147(10)2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32345745

RESUMO

Class III homeodomain leucine zipper (HD-ZIPIII) transcription factors play fundamental roles in controlling plant development. The known HD-ZIPIII target genes encode proteins involved in the production and dissipation of the auxin signal, HD-ZIPII transcription factors and components that feedback to regulate HD-ZIPIII expression or protein activity. Here, we have investigated the regulatory hierarchies of the control of MORE AXILLARY BRANCHES2 (MAX2) by the HD-ZIPIII protein REVOLUTA (REV). We found that REV can interact with the promoter of MAX2 In agreement, rev10D gain-of-function mutants had increased levels of MAX2 expression, while rev loss-of-function mutants showed lower levels of MAX2 in some tissues. Like REV, MAX2 plays known roles in the control of plant architecture, photobiology and senescence, which prompted us to initiate a multi-level analysis of growth phenotypes of hd-zipIII, max2 and respective higher order mutants thereof. Our data suggest a complex relationship of synergistic and antagonistic activities between REV and MAX2; these interactions appear to depend on the developmental context and do not all involve the direct regulation of MAX2 by REV.

2.
PLoS Genet ; 16(3): e1008678, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32203519

RESUMO

Plants have evolved strategies to avoid shade and optimize the capture of sunlight. While some species are tolerant to shade, plants such as Arabidopsis thaliana are shade-intolerant and induce elongation of their hypocotyl to outcompete neighboring plants. We report the identification of a developmental module acting downstream of shade perception controlling vascular patterning. We show that Arabidopsis plants react to shade by increasing the number and types of water-conducting tracheary elements in the vascular cylinder to maintain vascular density constant. Mutations in genes affecting vascular patterning impair the production of additional xylem and also show defects in the shade-induced hypocotyl elongation response. Comparative analysis of the shade-induced transcriptomes revealed differences between wild type and vascular patterning mutants and it appears that the latter mutants fail to induce sets of genes encoding biosynthetic and cell wall modifying enzymes. Our results thus set the stage for a deeper understanding of how growth and patterning are coordinated in a dynamic environment.

3.
Int J Mol Sci ; 20(18)2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31546885

RESUMO

RNA editing in plant mitochondria and plastids converts specific nucleotides from cytidine (C) to uridine (U). These editing events differ among plant species and are relevant to developmental stages or are impacted by environmental conditions. Proteins of the MORF family are essential components of plant editosomes. One of the members, MORF9, is considered the core protein of the editing complex and is involved in the editing of most sites in chloroplasts. In this study, the phenotypes of a T-DNA insertion line with loss of MORF9 and of the genetic complementation line of Arabidopsis were analyzed, and the editing efficiencies of plastid RNAs in roots, rosette leaves, and flowers from the morf9 mutant and the wild-type (WT) control were compared by bulk-cDNA sequencing. The results showed that most of the known MORF9-associated plastid RNA editing events in rosette leaves and flowers were similarly reduced by morf9 mutation, with the exception that the editing rate of the sites ndhB-872 and psbF-65 declined in the leaves and that of ndhB-586 decreased only in the flowers. In the roots, however, the loss of MORF9 had a much lower effect on overall plastid RNA editing, with nine sites showing no significant editing efficiency change, including accD-794, ndhD-383, psbZ-50, ndhF-290, ndhD-878, matK-706, clpP1-559, rpoA-200, and ndhD-674, which were reduced in the other tissues. Furthermore, we found that during plant aging, MORF9 mRNA level, but not the protein level, was downregulated in senescent leaves. On the basis of these observations, we suggest that MORF9-mediated RNA editing is tissue-dependent and the resultant organelle proteomes are pertinent to the specific tissue functions.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Plastídeos/metabolismo , Edição de RNA/fisiologia , RNA de Plantas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Mutação , Especificidade de Órgãos/fisiologia , Plastídeos/genética , RNA de Plantas/genética , Proteínas de Ligação a RNA/genética
4.
PLoS Genet ; 14(3): e1007273, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29554117

RESUMO

Several plant species require microbial associations for survival under different biotic and abiotic stresses. In this study, we show that Enterobacter sp. SA187, a desert plant endophytic bacterium, enhances yield of the crop plant alfalfa under field conditions as well as growth of the model plant Arabidopsis thaliana in vitro, revealing a high potential of SA187 as a biological solution for improving crop production. Studying the SA187 interaction with Arabidopsis, we uncovered a number of mechanisms related to the beneficial association of SA187 with plants. SA187 colonizes both the surface and inner tissues of Arabidopsis roots and shoots. SA187 induces salt stress tolerance by production of bacterial 2-keto-4-methylthiobutyric acid (KMBA), known to be converted into ethylene. By transcriptomic, genetic and pharmacological analyses, we show that the ethylene signaling pathway, but not plant ethylene production, is required for KMBA-induced plant salt stress tolerance. These results reveal a novel molecular communication process during the beneficial microbe-induced plant stress tolerance.


Assuntos
Adaptação Fisiológica , Arabidopsis/fisiologia , Enterobacter/fisiologia , Etilenos/metabolismo , Metionina/análogos & derivados , Estresse Fisiológico , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Regulação da Expressão Gênica de Plantas , Metionina/biossíntese , Metionina/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Potássio/metabolismo
5.
Plant Cell Environ ; 39(10): 2288-302, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27342100

RESUMO

The conserved miRNA393 family is thought to be involved in root elongation, leaf development and stress responses, but its role during seed germination and seedling establishment remains unclear. In this study, expression of the MIR393a/target module and its role in germinating rice (Oryza sativa L.) seeds were investigated. ß-Glucuronidase (GUS) analysis showed that MIR393a and OsTIR1 had spatial-temporal transcriptional activities in radicle roots, coleoptile tips and stomata cells, corresponding to a dynamic auxin response. miR393a promoted primary root elongation when rice seeds were germinated in air and inhibited coleoptile elongation and stomatal development when seeds were submerged. Under submergence, the expression of miR393a was inhibited, and then the auxin response was induced. In the process, OsTIR1 and OsAFB2, auxin receptor genes, were negatively regulated by miR393. We found that miR393a inhibited stomatal development and coleoptile elongation but promoted free indole acetic acid (IAA) accumulation in the rice coleoptile tips. In addition, exogenous abscisic acid (ABA) enhanced the expression of miR393 and inhibited coleoptile growth. Together, miR393a/target plays a role in coleoptile elongation and stomatal development via modulation of auxin signalling during seed germination and seedling establishment under submergence. This study provides new perspectives on the direct sowing of rice seeds in flooded paddy fields.


Assuntos
Germinação/genética , MicroRNAs/fisiologia , Oryza/genética , Plântula/genética , Ácidos Indolacéticos/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Oryza/crescimento & desenvolvimento , Estômatos de Plantas/genética , Estômatos de Plantas/crescimento & desenvolvimento , Plântula/crescimento & desenvolvimento , Transcrição Genética
6.
Plant Physiol ; 169(2): 1240-53, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26246448

RESUMO

An intricate network of antagonistically acting transcription factors mediates the formation of a flat leaf lamina of Arabidopsis (Arabidopsis thaliana) plants. In this context, members of the class III homeodomain leucine zipper (HD-ZIPIII) transcription factor family specify the adaxial domain (future upper side) of the leaf, while antagonistically acting KANADI transcription factors determine the abaxial domain (future lower side). Here, we used a messenger RNA sequencing approach to identify genes regulated by KANADI1 (KAN1) and subsequently performed a meta-analysis combining our data sets with published genome-wide data sets. Our analysis revealed that KAN1 acts upstream of several genes encoding auxin biosynthetic enzymes. When exposed to shade, we found three YUCCA genes, YUC2, YUC5, and YUC8, to be transcriptionally up-regulated, which correlates with an increase in the levels of free auxin. When ectopically expressed, KAN1 is able to transcriptionally repress these three YUC genes and thereby block shade-induced auxin biosynthesis. Consequently, KAN1 is able to strongly suppress shade-avoidance responses. Taken together, we hypothesize that HD-ZIPIII/KAN form the basis of a basic growth-promoting module. Hypocotyl extension in the shade and outgrowth of new leaves both involve auxin synthesis and signaling, which are under the direct control of HD-ZIPIII/KAN.


Assuntos
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Sistema Enzimático do Citocromo P-450/metabolismo , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Arabidopsis/crescimento & desenvolvimento , Sistema Enzimático do Citocromo P-450/genética , DNA de Plantas/metabolismo , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Plantas Geneticamente Modificadas , Sequências Reguladoras de Ácido Nucleico , Reprodutibilidade dos Testes , Análise de Sequência de RNA , Transdução de Sinais
7.
Development ; 141(24): 4772-83, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25395454

RESUMO

As sessile organisms, plants have to continuously adjust growth and development to ever-changing environmental conditions. At the end of the growing season, annual plants induce leaf senescence to reallocate nutrients and energy-rich substances from the leaves to the maturing seeds. Thus, leaf senescence is a means with which to increase reproductive success and is therefore tightly coupled to the developmental age of the plant. However, senescence can also be induced in response to sub-optimal growth conditions as an exit strategy, which is accompanied by severely reduced yield. Here, we show that class III homeodomain leucine zipper (HD-ZIPIII) transcription factors, which are known to be involved in basic pattern formation, have an additional role in controlling the onset of leaf senescence in Arabidopsis. Several potential direct downstream genes of the HD-ZIPIII protein REVOLUTA (REV) have known roles in environment-controlled physiological processes. We report that REV acts as a redox-sensitive transcription factor, and directly and positively regulates the expression of WRKY53, a master regulator of age-induced leaf senescence. HD-ZIPIII proteins are required for the full induction of WRKY53 in response to oxidative stress, and mutations in HD-ZIPIII genes strongly delay the onset of senescence. Thus, a crosstalk between early and late stages of leaf development appears to contribute to reproductive success.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Proteínas de Homeodomínio/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Fatores de Transcrição/metabolismo , Oxirredutases do Álcool , Imunoprecipitação da Cromatina , Cisteína Endopeptidases , Peróxido de Hidrogênio/metabolismo , Zíper de Leucina/genética , Folhas de Planta/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição/genética
8.
J Integr Plant Biol ; 56(6): 518-26, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24528801

RESUMO

The Arabidopsis (Arabidopsis thaliana L.) genome encodes for four distinct classes of homeodomain leucine-zipper (HD-ZIP) transcription factors (HD-ZIPI to HD-ZIPIV), which are all organized in multi-gene families. HD-ZIP transcription factors act as sequence-specific DNA-binding proteins that are able to control the expression level of target genes. While HD-ZIPI and HD-ZIPII proteins are mainly associated with environmental responses, HD-ZIPIII and HD-ZIPIV are primarily known to act as patterning factors. Recent studies have challenged this view. It appears that several of the different HD-ZIP families interact genetically to align both morphogenesis and environmental responses, most likely by modulating phytohormone-signaling networks.


Assuntos
Meio Ambiente , Proteínas de Homeodomínio/metabolismo , Zíper de Leucina , Desenvolvimento Vegetal , Transdução de Sinal Luminoso , Estresse Fisiológico
9.
PLoS One ; 8(10): e77341, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24155946

RESUMO

Plant organ development and polarity establishment is mediated by the action of several transcription factors. Among these, the KANADI (KAN) subclade of the GARP protein family plays important roles in polarity-associated processes during embryo, shoot and root patterning. In this study, we have identified a set of potential direct target genes of KAN1 through a combination of chromatin immunoprecipitation/DNA sequencing (ChIP-Seq) and genome-wide transcriptional profiling using tiling arrays. Target genes are over-represented for genes involved in the regulation of organ development as well as in the response to auxin. KAN1 affects directly the expression of several genes previously shown to be important in the establishment of polarity during lateral organ and vascular tissue development. We also show that KAN1 controls through its target genes auxin effects on organ development at different levels: transport and its regulation, and signaling. In addition, KAN1 regulates genes involved in the response to abscisic acid, jasmonic acid, brassinosteroids, ethylene, cytokinins and gibberellins. The role of KAN1 in organ polarity is antagonized by HD-ZIPIII transcription factors, including REVOLUTA (REV). A comparison of their target genes reveals that the REV/KAN1 module acts in organ patterning through opposite regulation of shared targets. Evidence of mutual repression between closely related family members is also shown.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Genes de Plantas/genética , Fatores de Transcrição/metabolismo , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Sequência de Bases , Imunoprecipitação da Cromatina , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ontologia Genética , Proteínas de Homeodomínio/metabolismo , Ácidos Indolacéticos/farmacologia , Dados de Sequência Molecular , Organogênese/efeitos dos fármacos , Organogênese/genética , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/genética , Análise de Sequência de DNA , Fatores de Transcrição/genética , Transcrição Genética/efeitos dos fármacos
10.
Mech Dev ; 130(1): 25-33, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22781836

RESUMO

Stem cells in the shoot apex of plants produce cells required for the formation of new leaves. Adult leaves are composed of multiple tissue layers arranged along the dorso-ventral (adaxial/abaxial) axis. Class III homeodomain leucine zipper (HD-ZIPIII) transcription factors play an important role in the set-up of leaf polarity in plants. Loss of HD-ZIPIII function results in strongly misshapen leaves and in severe cases fosters the consumption of the apical stem cells, thus causing a growth arrest in mutant plants. HD-ZIPIII mRNA is under tight control by microRNAs 165/166. In addition to the microRNA-action a second layer of regulation is established by LITTLE ZIPPER (ZPR)-type microProteins, which can interact with HD-ZIPIII proteins, forming attenuated protein complexes. Here we show that REVOLUTA (REV, a member of the HD-ZIPIII family) directly regulates the expression of ARGONAUTE10 (AGO10), ZPR1 and ZPR3. Because AGO10 was shown to dampen microRNA165/6 function, REV establishes a positive feedback loop on its own activity. Since ZPR-type microProteins are known to reduce HD-ZIPIII protein activity, REV concomitantly establishes a negative feedback loop. We propose that the interconnection of these microRNA/microProtein feedback loops regulates polarity set-up and stem cell activity in plants.


Assuntos
MicroRNAs , Folhas de Planta , Fatores de Transcrição , Retroalimentação Fisiológica , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/metabolismo , Homeostase , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Células-Tronco , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
11.
New Phytol ; 196(1): 149-61, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22846038

RESUMO

• MicroRNA (miRNA)-mediated regulation of auxin signaling components plays a critical role in plant development. miRNA expression and functional diversity contribute to the complexity of regulatory networks of miRNA/target modules. • This study functionally characterizes two members of the rice (Oryza sativa) miR393 family and their target genes, OsTIR1 and OsAFB2 (AUXIN SIGNALING F-BOX), the two closest homologs of Arabidopsis TRANSPORT INHIBITOR RESPONSE 1 (TIR1). • We found that the miR393 family members possess distinctive expression patterns, with miR393a expressed mainly in the crown and lateral root primordia, as well as the coleoptile tip, and miR393b expressed in the shoot apical meristem. Transgenic plants overexpressing miR393a/b displayed a severe phenotype with hallmarks of altered auxin signaling, mainly including enlarged flag leaf inclination and altered primary and crown root growth. Furthermore, OsAFB2- and OsTIR1-suppressed lines exhibited increased inclination of flag leaves at the booting stage, resembling miR393-overexpressing plants. Moreover, yeast two-hybrid and bimolecular fluorescence complementation assays showed that OsTIR1 and OsAFB2 interact with OsIAA1. • Expression diversification of miRNA393 implies the potential role of miRNA regulation during species evolution. The conserved mechanisms of the miR393/target module indicate the fundamental importance of the miR393-mediated regulation of auxin signal transduction in rice.


Assuntos
MicroRNAs/genética , Oryza/crescimento & desenvolvimento , Oryza/genética , Folhas de Planta/anatomia & histologia , Proteínas de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Homologia de Sequência de Aminoácidos , Ácido 2,4-Diclorofenoxiacético/toxicidade , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Genes de Plantas/genética , Resistência a Herbicidas/genética , MicroRNAs/metabolismo , Oryza/anatomia & histologia , Oryza/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Ligação Proteica/efeitos dos fármacos , Sementes/efeitos dos fármacos , Sementes/genética , Sementes/crescimento & desenvolvimento
12.
FEBS J ; 278(24): 4797-810, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21972902

RESUMO

Hydrogen peroxide (H(2)O(2)) is known to be a key player in apoptosis in animals. The components and pathways regulating H(2)O(2)-induced programmed cell death in plants, however, remain largely unknown. In the present study, rice transgenic lines overexpressing Bcl-2, a human apoptotic suppressor, were obtained. These transgenic lines showed increased tolerance to high levels of H(2)O(2), resulting in increased seed germination rates, root elongation, root tip cell viability and chlorophyll retention compared to control lines. In the control lines, treatment with H(2)O(2) resulted in DNA laddering and a clear terminal transferase dUTP nick end labeling signal, which are the hallmarks of programmed cell death. However, this effect was not detected in the Bcl-2-overexpressing transgenic lines. Further investigations indicated that Bcl-2 suppressed H(2)O(2)-induced programmed cell death but did not inhibit stress-elicited reactive oxygen species production in rice. RT-PCR revealed that the expression of the two vacuolar processing enzyme genes (i.e. OsVPE2 and OsVPE3) was dramatically induced by H(2)O(2) in the wild-type line but not in the Bcl-2-overexpressing line. Moreover, treatment with H(2)O(2) resulted in the disruption of the vacuolar membrane in the wild-type line. The expression levels of OsVPE1 and OsVPE4 did not significantly differ between the wild-type line and the transgenic line that was treated or untreated with H(2)O(2). The similar roles of Bcl-2 and OsVPEs during endogenous reactive oxygen species-triggered programmed cell death were also confirmed by NaCl stress in rice. To our knowledge, the present study is the first to demonsatrate that Bcl-2 overexpression inhibits H(2)O(2)-induced programmed cell death and enhances H(2)O(2) tolerance. We propose that Bcl-2 overexpression in rice suppresses the transcriptional activation of OsVPE2 and OsVPE3, but not of OsVPE1 or OsVPE4.


Assuntos
Apoptose/efeitos dos fármacos , Cisteína Endopeptidases/fisiologia , Peróxido de Hidrogênio/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Sequência de Aminoácidos , Sobrevivência Celular/efeitos dos fármacos , Cisteína Endopeptidases/genética , Humanos , Dados de Sequência Molecular , Oryza/genética , Plantas Geneticamente Modificadas/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Espécies Reativas de Oxigênio/metabolismo , Alinhamento de Sequência , Ativação Transcricional/efeitos dos fármacos , Vacúolos/efeitos dos fármacos , Vacúolos/fisiologia
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