Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Plant Physiol Biochem ; 166: 328-340, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34147725

RESUMO

Cytokinin (CK) is an important plant hormone that promotes plant cell division and differentiation, and participates in salt response under osmotic stress. LOGs (LONELY GUY) are CK-activating enzymes involved in CK synthesis. The LOG gene family has not been comprehensively characterized in cotton. In this study we identified 151 LOG genes from nine plant species, including 28 LOG genes in Gossypium hirsutum. Phylogenetic analysis divided LOG genes into three groups. Exon/intron structures and protein motifs of GhLOG genes were highly conserved. Synteny analysis revealed that several gene loci were highly conserved between the A and D sub-genomes of G. hirsutum with purifying selection pressure during evolution. Expression profiles showed that most LOG genes were constitutively expressed in eight different tissues. Furthermore, LOG genes can be regulated by abiotic stresses and phytohormone treatments. Moreover, subcellular localization revealed that GhLOG3_At resides inside the cell membrane. Overexpression of GhLOG3 enhanced salt tolerance in Arabidopsis. Virus-induced gene silencing (VIGS) of GhLOG3_At in cotton enhanced sensitivity of plants to salt stress with increased H2O2 contents and decreased chlorophyll and proline (PRO) activity. Our results suggested that GhLOG3_At induces salt stress tolerance in cotton, and provides a basis for the use of CK synthesis genes to regulate cotton growth and stress resistance.


Assuntos
Gossypium , Tolerância ao Sal , Regulação da Expressão Gênica de Plantas , Gossypium/genética , Gossypium/metabolismo , Peróxido de Hidrogênio , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genética
2.
Int J Mol Sci ; 22(6)2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33809404

RESUMO

Dynamic remodeling of the actin cytoskeleton plays a central role in the elongation of cotton fibers, which are the most important natural fibers in the global textile industry. Here, a high-resolution mapping approach combined with comparative sequencing and a transgenic method revealed that a G65V substitution in the cotton actin Gh_D04G0865 (GhACT17D in the wild-type) is responsible for the Gossypium hirsutum Ligon lintless-1 (Li1) mutant (GhACT17DM). In the mutant GhACT17DM from Li1 plant, Gly65 is substituted with valine on the lip of the nucleotide-binding domain of GhACT17D, which probably affects the polymerization of F-actin. Over-expression of GhACT17DM, but not GhACT17D, driven by either a CaMV35 promoter or a fiber-specific promoter in cotton produced a Li1-like phenotype. Compared with the wild-type control, actin filaments in Li1 fibers showed higher growth and shrinkage rates, decreased filament skewness and parallelness, and increased filament density. Taken together, our results indicate that the incorporation of GhACT17DM during actin polymerization disrupts the establishment and dynamics of the actin cytoskeleton, resulting in defective fiber elongation and the overall dwarf and twisted phenotype of the Li1 mutant.


Assuntos
Citoesqueleto de Actina/metabolismo , Actinas/genética , Fibra de Algodão , Gossypium/genética , Mutação/genética , Actinas/química , Sequência de Aminoácidos , Sequência Conservada , Estudos de Associação Genética , Gossypium/crescimento & desenvolvimento , Fenótipo , Mapeamento Físico do Cromossomo , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Homologia Estrutural de Proteína
3.
Environ Microbiol ; 23(4): 1991-2003, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33185953

RESUMO

The soil-borne ascomycete Verticillium dahliae causes wilt disease in more than two hundred dicotyledonous plants including the economically important crop cotton, and results in a severe reduction in cotton fiber yield and quality. During infection, V. dahliae secretes numerous secondary metabolites, which act as toxic factors to promote the infection process. However, the mechanism underlying how V. dahliae secondary metabolites regulate cotton infection remains largely unexplored. In this study, we report that VdBre1, an ubiquitin ligase (E3) enzyme to modify H2B, regulates radial growth and conidia production of V. dahliae. The VdBre1 deletion strains show nonpathogenic symptoms on cotton, and microscopic inspection and penetration assay indicated that penetration ability of the ∆VdBre1 strain was dramatically reduced. RNA-seq revealed that a total of 1643 differentially expressed genes between the ∆VdBre1 strain and the wild type strain V592, among which genes related to lipid metabolism were significantly overrepresented. Remarkably, the volume of lipid droplets in the ∆VdBre1 conidia was shown to be smaller than that of wild-type strains. Further metabolomics analysis revealed that the pathways of lipid metabolism and secondary metabolites, such as steroid biosynthesis and metabolism of terpenoids and polyketides, have dramatically changed in the ∆VdBre1 metabolome. Taken together, these results indicate that VdBre1 plays crucial roles in cotton infection and pathogenecity, by globally regulating lipid metabolism and secondary metabolism of V. dahliae.


Assuntos
Verticillium , Ascomicetos , Resistência à Doença , Gossypium , Metabolismo dos Lipídeos , Doenças das Plantas , Proteínas de Plantas/metabolismo , Verticillium/genética , Verticillium/metabolismo
4.
Plant J ; 104(4): 1105-1116, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32891072

RESUMO

Root nutation indicates the behavior that roots grow in a waving and skewing way due to unequal growth rates on different sides. Although a few developmental and environmental factors have been reported, genetic pathways mediating this process are obscure. We report here that the Arabidopsis CrRLK1L family member FERONIA (FER) is critical for root nutation. Functional loss of FER resulted in enhanced root waviness on tilted plates or roots forming anti-clockwise coils on horizontal plates. Suppressing polar auxin transport, either by pharmacological treatment or by introducing mutations at PIN-FORMED2 (PIN2) or AUXIN RESISTANT1 (AUX1), suppressed the asymmetric root growth (ARG) in fer-4, a null mutant of FER, indicating that FER suppression of ARG depends on polar auxin transport. We further showed by pharmacological treatments that dynamic microtubule organization and Ca2+ signaling are both critical for FER-mediated ARG. Results presented here demonstrate a key role of FER in mediating root nutating growth, through PIN2- and AUX1-mediated auxin transport, through dynamic microtubule organization, and through Ca2+ signaling.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Ácidos Indolacéticos/metabolismo , Fosfotransferases/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Transdução de Sinais , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Transporte Biológico , Sinalização do Cálcio , Microtúbulos/metabolismo , Mutação , Fosfotransferases/genética
5.
Nat Plants ; 6(7): 800-808, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32514144

RESUMO

Root nodule symbiosis enables nitrogen fixation in legumes and, therefore, improves crop production for sustainable agriculture1,2. Environmental nitrate levels affect nodulation and nitrogen fixation, but the mechanisms by which legume plants modulate nitrate uptake to regulate nodule symbiosis remain unclear1. Here, we identify a member of the Medicago truncatula nitrate peptide family (NPF), NPF7.6, which is expressed specifically in the nodule vasculature. NPF7.6 localizes to the plasma membrane of nodule transfer cells (NTCs), where it functions as a high-affinity nitrate transporter. Transfer cells show characteristic wall ingrowths that enhance the capacity for membrane transport at the apoplasmic-symplasmic interface between the vasculature and surrounding tissues3. Importantly, knockout of NPF7.6 using CRISPR-Cas9 resulted in developmental defects of the nodule vasculature, with excessive expansion of NTC plasma membranes. npf7.6 nodules showed severely compromised nitrate responsiveness caused by an attenuated ability to transport nitrate. Moreover, npf7.6 nodules exhibited disturbed nitric oxide homeostasis and a notable decrease in nitrogenase activity. Our findings indicate that NPF7.6 has been co-opted into a regulatory role in nodulation, functioning in nitrate uptake through NTCs to fine-tune nodule symbiosis in response to fluctuating environmental nitrate status. These observations will inform efforts to optimize nitrogen fixation in legume crops.


Assuntos
Nitratos/metabolismo , Nódulos Radiculares de Plantas/metabolismo , Simbiose , Proteínas de Transporte de Ânions/metabolismo , Transporte Biológico , Membrana Celular/metabolismo , Medicago truncatula/metabolismo , Fixação de Nitrogênio , Proteínas de Plantas/metabolismo , Nódulos Radiculares de Plantas/citologia , Nódulos Radiculares de Plantas/fisiologia
6.
Sci China Life Sci ; 63(8): 1213-1226, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32221813

RESUMO

Legumes have evolved a symbiotic relationship with rhizobial bacteria and their roots form unique nitrogen-fixing organs called nodules. Studies have shown that abiotic and biotic stresses alter the profile of gene expression and transcript mobility in plants. However, little is known about the systemic transport of RNA between roots and shoots in response to rhizobial infection on a genome-wide scale during the formation of legume-rhizobia symbiosis. In our study, we found that two soybean (Glycine max) cultivars, Peking and Williams, show a high frequency of single nucleotide polymorphisms; this allowed us to characterize the origin and mobility of transcripts in hetero-grafts of these two cultivars. We identified 4,552 genes that produce mobile RNAs in soybean, and found that rhizobial infection triggers mass transport of mRNAs between shoots and roots at the early stage of nodulation. The majority of these mRNAs are of relatively low abundance and their transport occurs in a selective manner in soybean plants. Notably, the mRNAs that moved from shoots to roots at the early stage of nodulation were enriched in many nodule-related responsive processes. Moreover, the transcripts of many known symbiosis-related genes that are induced by rhizobial infection can move between shoots and roots. Our findings provide a deeper understanding of endogenous RNA transport in legume-rhizobia symbiotic processes.


Assuntos
Infecções/genética , Brotos de Planta/genética , RNA Mensageiro/metabolismo , Rhizobium/genética , Nódulos Radiculares de Plantas/genética , Soja/genética , Sequência de Bases , Transporte Biológico , Regulação da Expressão Gênica de Plantas , Biblioteca Genômica , Geografia , Infecções/metabolismo , Nucleotídeos/química , Polimorfismo Genético , Rhizobium/metabolismo , Simbiose
7.
Sheng Wu Gong Cheng Xue Bao ; 35(8): 1520-1528, 2019 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-31441623

RESUMO

Actin filaments play an important role in fungal life processes such as growth, development and cytokinesis. The expression vector pSULPH-Lifeact-mCherry of fluorescent mCherry-labeled actin was transferred into Verticillium dahliae Kleb. wild type V592 by the genetic transformation system mediated by Agrobacterium tumefaciens to obtain the stable fluorescent labeled actin strain V592/Lifeact-mCherry. Then we detected its biological phenotype and the dynamic changes of actin fluorescence during the process of spore germination, mycelial growth and development. There was no significant difference in the colony morphology, colonial growth rate, sporulation and germination rate between the fluorescent labeled actin strain and the wild type. The actin fluorescence signal was observed at the tip of the conidia and hyphae and the septum clearly. Actin participated in the formation of the contractile actomyosin ring (CAR) during cytokinesis by observing the dynamic behavior of the actin in the process of hyphal septum formation. The fluorescent labeled actin strain can be used to study the dynamics of actin in fungal development to provide theoretical and practical support for further study of the mechanism of actin in fungal development and pathogenesis.


Assuntos
Verticillium , Actinas , Agrobacterium tumefaciens , Doenças das Plantas , Esporos Fúngicos
8.
Nat Plants ; 5(5): 498-504, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31040442

RESUMO

Cotton (Gossypium hirsutum) fibres consist of single cells that grow in a highly polarized manner, assumed to be controlled by the cytoskeleton1-3. However, how the cytoskeletal organization and dynamics underpin fibre development remains unexplored. Moreover, it is unclear whether cotton fibres expand via tip growth or diffuse growth2-4. We generated stable transgenic cotton plants expressing fluorescent markers of the actin and microtubule cytoskeleton. Live-cell imaging revealed that elongating cotton fibres assemble a cortical filamentous actin network that extends along the cell axis to finally form actin strands with closed loops in the tapered fibre tip. Analyses of F-actin network properties indicate that cotton fibres have a unique actin organization that blends features of both diffuse and tip growth modes. Interestingly, typical actin organization and endosomal vesicle aggregation found in tip-growing cell apices were not observed in fibre tips. Instead, endomembrane compartments were evenly distributed along the elongating fibre cells and moved bi-directionally along the fibre shank to the fibre tip. Moreover, plus-end tracked microtubules transversely encircled elongating fibre shanks, reminiscent of diffusely growing cells. Collectively, our findings indicate that cotton fibres elongate via a unique tip-biased diffuse growth mode.


Assuntos
Fibra de Algodão , Citoesqueleto/ultraestrutura , Gossypium/ultraestrutura , Actinas/ultraestrutura , Proteínas de Fluorescência Verde , Imageamento Tridimensional , Microscopia Intravital/métodos , Microtúbulos/ultraestrutura
9.
J Exp Bot ; 70(12): 3035-3041, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-30882862

RESUMO

Microtubule-dependent microtubule nucleation occurs on the lateral surface of pre-existing microtubules and provides a highly efficient means of amplifying their populations and reorganizing their architectures. The γ­tubulin ring complex serves as the template to initiate nascent microtubule polymerization. Augmin, a hetero-octameric protein complex, acts as a recruiting factor to target the γ­tubulin ring complex to pre-existing microtubules and trigger new microtubule growth. Although microtubule-dependent microtubule nucleation has been extensively studied in both animal and plant cells, it remains unclear how the augmin complex assembles in plant cells, especially in cell-cycle-specific and cell-type-specific manners, and how its spatial structure orchestrates the nucleation geometry. In this review, we summarize the advances in knowledge of augmin-dependent microtubule nucleation and the regulation of its geometry, and highlight recent findings and emerging questions concerning the role of the augmin complex in establishing microtubule arrays and the cell-cycle-specific composition of augmin in plant cells.


Assuntos
Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Células Vegetais/metabolismo , Proteínas de Plantas/metabolismo , Ciclo Celular
10.
J Integr Plant Biol ; 61(4): 388-393, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30226291

RESUMO

Numerous fluorescent marker lines are currently available to visualize microtubule (MT) architecture and dynamics in living plant cells, such as markers expressing p35S::GFP-MBD or p35S::GFP-TUB6. However, these MT marker lines display obvious defects that affect plant growth or produce unstable fluorescent signals. Here, a series of new marker lines were developed, including the pTUB6::VisGreen-TUB6-expressing line in which TUB6 is under the control of its endogenous regulatory elements and eGFP is replaced with VisGreen, a brighter fluorescent protein. Moreover, two different markers were combined into one expression vector and developed two dual-marker lines. These marker lines produce bright, stable fluorescent signals in various tissues, and greatly shorten the screening process for generating dual-marker lines. These new marker lines provide a novel resource for MT research.


Assuntos
Microtúbulos/metabolismo , Células Vegetais/metabolismo , Arabidopsis/citologia , Arabidopsis/genética , Biomarcadores/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Plantas Geneticamente Modificadas
11.
New Phytol ; 221(2): 1049-1059, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30156704

RESUMO

In plants, the actin cytoskeleton plays a central role in regulating intracellular transport and trafficking in the endomembrane system. Work in legumes suggested that during nodulation, the actin cytoskeleton coordinates numerous cellular processes in the development of nitrogen-fixing nodules. However, we lacked live-cell visualizations demonstrating dynamic remodeling of the actin cytoskeleton during infection droplet release and symbiosome development. Here, we generated transgenic Medicago truncatula lines stably expressing the fluorescent actin marker ABD2-GFP, and utilized live-cell imaging to reveal the architecture and dynamics of the actin cytoskeleton during nodule development. Live-cell observations showed that different zones in nitrogen-fixing nodules exhibit distinct actin architectures and infected cells display five characteristic actin architectures during nodule development. Live-cell imaging combined with three-dimensional reconstruction demonstrated that dense filamentous-actin (F-actin) arrays channel the elongation of infection threads and the release of infection droplets, an F-actin network encircles freshly-released rhizobia, and short F-actin fragments and actin dots around radially distributed symbiosomes. Our findings suggest an important role of the actin cytoskeleton in infection droplet release, symbiosome development and maturation, and provide significant insight into the cellular mechanisms underlying nodule development and nitrogen fixation during legume-rhizobia interactions.


Assuntos
Citoesqueleto de Actina/metabolismo , Medicago truncatula/genética , Sinorhizobium meliloti/fisiologia , Simbiose , Actinas/metabolismo , Genes Reporter , Medicago truncatula/microbiologia , Fixação de Nitrogênio , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Nodulação , Plantas Geneticamente Modificadas , Nódulos Radiculares de Plantas/microbiologia
12.
Curr Biol ; 28(8): 1311-1317.e3, 2018 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-29657114

RESUMO

Plant cells do not possess centrosomes, which serve as the microtubule organizing center in animal cells; how plant cell microtubule arrays are established and maintain their dynamics remain poorly understood [1]. The γ-tubulin complex and the katanin complex play central roles in the organization of plant cortical microtubules [2-6]. Previously, we reported that the augmin complex recruits the γ-tubulin complex to preexisting microtubules and initiates microtubule nucleation [7]. Moreover, we described how an intricate interaction between the katanin p60 subunit KTN1 and the p80 subunit KTN80 confers precise microtubule severing at either microtubule branching nucleation sites or crossovers [8]. Here, we observed that augmin preferentially localizes to microtubule crossovers. Live-cell observations and analyses revealed that, whereas a small portion of crossover-localized augmin complexes act to trigger nascent microtubule nucleation, the majority function in stabilizing the architecture of microtubule crossovers. Finally, genetic analyses and computational modeling confirmed that suppression of augmin activity elevates microtubule severing frequency and facilitates the formation of aligned microtubule arrays. Combined, our findings reveal an unexpected role of augmin and demonstrate that augmin antagonizes katanin-mediated microtubule severing. Furthermore, we propose a novel mechanism for how augmin determines self-organization of plant cortical microtubules by preventing microtubule severing at crossovers in addition to triggering microtubule nucleation.


Assuntos
Proteínas de Arabidopsis/metabolismo , Katanina/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Centro Organizador dos Microtúbulos/fisiologia , Adenosina Trifosfatases/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/fisiologia , Proteínas Associadas aos Microtúbulos/fisiologia , Centro Organizador dos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Microtúbulos/fisiologia , Células Vegetais/metabolismo , Plantas/metabolismo , Tubulina (Proteína)/metabolismo
13.
Environ Microbiol ; 20(4): 1607-1621, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29575486

RESUMO

The vascular wilt fungus Verticillium dahliae is one of the most destructive pathogens of cotton (Gossypium hirsutum) and many other economically important dicot plants. Fungal pathogens require Myosin-mediated actomyosin motility system for colonization of their host plants; however, the mechanisms underlying this process have not been fully characterized for V. dahliae. Here, in a knock-out experiment, we characterized the role of VdMyo5, a member of the Myosin V family, before and during infection of cotton and Arabidopsis thaliana. The VdMyo5 deletion mutant (ΔVdmyo5) fungi showed obvious defects in the development of conidia and the polarized elongation of vegetative hyphae, but no inhibition of host root penetration. Overall, the ΔVdmyo5 fungi exhibited dramatically reduced virulence in cotton and Arabidopsis, with almost no colonization in sections of host vascular tissue. We found labelled Myosin5-GFP to be specifically enriched at the hyphal tip, co-localized with FM4-64 labelled Spitzenkörper, which is the vesicle supply centre in filamentous fungi. Comparative secretome analysis revealed that proteins associated with cell wall modification and degradation of reactive oxygen species were significantly altered in mutant strains. Our results indicate that Myosin5 is required for vegetative growth and full virulence, possibly by regulating vesicle transport. The findings provide important insight into the cellular mechanisms of Verticillium pathogenesis.


Assuntos
Actomiosina/metabolismo , Arabidopsis/microbiologia , Gossypium/microbiologia , Miosina Tipo V/metabolismo , Doenças das Plantas/microbiologia , Verticillium/patogenicidade , Técnicas de Inativação de Genes , Hifas/crescimento & desenvolvimento , Miosina Tipo V/genética , Raízes de Plantas/microbiologia , Esporos Fúngicos/crescimento & desenvolvimento , Verticillium/genética , Verticillium/metabolismo , Virulência/genética
14.
New Phytol ; 218(1): 298-309, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29281751

RESUMO

Powdery mildew is one of the most devastating diseases of wheat. To date, few powdery mildew resistance genes have been cloned from wheat due to the size and complexity of the wheat genome. Triticum urartu is the progenitor of the A genome of wheat and is an important source for powdery mildew resistance genes. Using molecular markers designed from scaffolds of the sequenced T. urartu accession and standard map-based cloning, a powdery mildew resistance locus was mapped to a 356-kb region, which contains two nucleotide-binding and leucine-rich repeat domain (NB-LRR) protein-encoding genes. Virus-induced gene silencing, single-cell transient expression, and stable transformation assays demonstrated that one of these two genes, designated Pm60, confers resistance to powdery mildew. Overexpression of full-length Pm60 and two allelic variants in Nicotiana benthamiana leaves induced hypersensitive cell death response, but expression of the coiled-coil domain alone was insufficient to induce hypersensitive response. Yeast two-hybrid, bimolecular fluorescence complementation and luciferase complementation imaging assays showed that Pm60 protein interacts with its neighboring NB-containing protein, suggesting that they might be functionally related. The identification and cloning of this novel wheat powdery mildew resistance gene will facilitate breeding for disease resistance in wheat.


Assuntos
Ascomicetos/fisiologia , Resistência à Doença/genética , Genes de Plantas , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Triticum/genética , Triticum/microbiologia , Alelos , Sequência de Bases , Morte Celular , Inativação Gênica , Loci Gênicos , Mapeamento Físico do Cromossomo , Doenças das Plantas/genética , Folhas de Planta/citologia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Domínios Proteicos , Análise de Célula Única , Tabaco/genética , Transformação Genética , Triticum/imunologia
15.
EMBO J ; 36(23): 3435-3447, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-28978669

RESUMO

The microtubule (MT)-severing enzyme katanin triggers dynamic reorientation of cortical MT arrays that play crucial functions during plant cell morphogenesis, such as cell elongation, cell wall biosynthesis, and hormonal signaling. MT severing specifically occurs at crossover or branching nucleation sites in living Arabidopsis cells. This differs from the random severing observed along the entire length of single MTs in vitro and strongly suggests that a precise control mechanism must exist in vivo However, how katanin senses and cleaves at MT crossover and branching nucleation sites in vivo has remained unknown. Here, we show that the katanin p80 subunit KTN80 confers precision to MT severing by specific targeting of the katanin p60 subunit KTN1 to MT cleavage sites and that KTN1 is required for oligomerization of functional KTN80-KTN1 complexes that catalyze severing. Moreover, our findings suggest that the katanin complex in Arabidopsis is composed of a hexamer of KTN1-KTN80 heterodimers that sense MT geometry to confer precise MT severing. Our findings shed light on the precise control mechanism of MT severing in plant cells, which may be relevant for other eukaryotes.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Katanina/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Genes de Plantas , Katanina/química , Katanina/genética , Microtúbulos/metabolismo , Complexos Multiproteicos/química , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Mutação , Plantas Geneticamente Modificadas , Estrutura Quaternária de Proteína , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo
16.
Mol Cell ; 67(4): 702-710.e4, 2017 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-28757206

RESUMO

Methylation and nitric oxide (NO)-based S-nitrosylation are highly conserved protein posttranslational modifications that regulate diverse biological processes. In higher eukaryotes, PRMT5 catalyzes Arg symmetric dimethylation, including key components of the spliceosome. The Arabidopsis prmt5 mutant shows severe developmental defects and impaired stress responses. However, little is known about the mechanisms regulating the PRMT5 activity. Here, we report that NO positively regulates the PRMT5 activity through S-nitrosylation at Cys-125 during stress responses. In prmt5-1 plants, a PRMT5C125S transgene, carrying a non-nitrosylatable mutation at Cys-125, fully rescues the developmental defects, but not the stress hypersensitive phenotype and the responsiveness to NO during stress responses. Moreover, the salt-induced Arg symmetric dimethylation is abolished in PRMT5C125S/prmt5-1 plants, correlated to aberrant splicing of pre-mRNA derived from a stress-related gene. These findings define a mechanism by which plants transduce stress-triggered NO signal to protein methylation machinery through S-nitrosylation of PRMT5 in response to environmental alterations.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Óxido Nítrico/metabolismo , Plantas Geneticamente Modificadas/enzimologia , Processamento de Proteína Pós-Traducional , Proteína-Arginina N-Metiltransferases/metabolismo , Estresse Fisiológico , Adaptação Fisiológica , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Cisteína , Regulação da Expressão Gênica de Plantas , Metilação , Mutação , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Proteômica/métodos , Precursores de RNA/genética , Precursores de RNA/metabolismo , Splicing de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Transdução de Sinais
17.
Plant Physiol ; 174(2): 1151-1166, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28455404

RESUMO

To better understand the molecular mechanisms behind plant growth and leaf senescence in monocot plants, we identified a mutant exhibiting dwarfism and an early-senescence leaf phenotype, termed dwarf and early-senescence leaf1 (del1). Histological analysis showed that the abnormal growth was caused by a reduction in cell number. Further investigation revealed that the decline in cell number in del1 was affected by the cell cycle. Physiological analysis, transmission electron microscopy, and TUNEL assays showed that leaf senescence was triggered by the accumulation of reactive oxygen species. The DEL1 gene was cloned using a map-based approach. It was shown to encode a pectate lyase (PEL) precursor that contains a PelC domain. DEL1 contains all the conserved residues of PEL and has strong similarity with plant PelC. DEL1 is expressed in all tissues but predominantly in elongating tissues. Functional analysis revealed that mutation of DEL1 decreased the total PEL enzymatic activity, increased the degree of methylesterified homogalacturonan, and altered the cell wall composition and structure. In addition, transcriptome assay revealed that a set of cell wall function- and senescence-related gene expression was altered in del1 plants. Our research indicates that DEL1 is involved in both the maintenance of normal cell division and the induction of leaf senescence. These findings reveal a new molecular mechanism for plant growth and leaf senescence mediated by PECTATE LYASE-LIKE genes.


Assuntos
Genes de Plantas , Oryza/enzimologia , Oryza/genética , Desenvolvimento Vegetal/genética , Folhas de Planta/crescimento & desenvolvimento , Polissacarídeo-Liases/genética , Sequência de Aminoácidos , Contagem de Células , Ciclo Celular/genética , Morte Celular/genética , Parede Celular/metabolismo , Clonagem Molecular , Esterificação , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Modelos Biológicos , Mutação/genética , Oryza/crescimento & desenvolvimento , Pectinas/metabolismo , Fenótipo , Filogenia , Folhas de Planta/genética , Folhas de Planta/ultraestrutura , Polissacarídeo-Liases/química , Polissacarídeo-Liases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transcriptoma/genética
18.
PLoS Genet ; 12(10): e1006266, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27768706

RESUMO

How cell shape is controlled is a fundamental question in developmental biology, but the genetic and molecular mechanisms that determine cell shape are largely unknown. Arabidopsis trichomes have been used as a good model system to investigate cell shape at the single-cell level. Here we describe the trichome cell shape 1 (tcs1) mutants with the reduced trichome branch number in Arabidopsis. TCS1 encodes a coiled-coil domain-containing protein. Pharmacological analyses and observations of microtubule dynamics show that TCS1 influences the stability of microtubules. Biochemical analyses and live-cell imaging indicate that TCS1 binds to microtubules and promotes the assembly of microtubules. Further results reveal that TCS1 physically associates with KCBP/ZWICHEL, a microtubule motor involved in the regulation of trichome branch number. Genetic analyses indicate that kcbp/zwi is epistatic to tcs1 with respect to trichome branch number. Thus, our findings define a novel genetic and molecular mechanism by which TCS1 interacts with KCBP to regulate trichome cell shape by influencing the stability of microtubules.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Proteínas de Ligação a Calmodulina/genética , Forma Celular/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/metabolismo , Proteínas de Ligação a Calmodulina/metabolismo , Hipocótilo/genética , Hipocótilo/crescimento & desenvolvimento , Proteínas Associadas aos Microtúbulos , Microtúbulos/genética , Microtúbulos/metabolismo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Ligação Proteica , Plântula/genética , Plântula/crescimento & desenvolvimento , Tricomas/genética , Tricomas/crescimento & desenvolvimento , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo
19.
Proc Natl Acad Sci U S A ; 113(40): 11348-11353, 2016 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-27647923

RESUMO

Cellulose, often touted as the most abundant biopolymer on Earth, is a critical component of the plant cell wall and is synthesized by plasma membrane-spanning cellulose synthase (CESA) enzymes, which in plants are organized into rosette-like CESA complexes (CSCs). Plants construct two types of cell walls, primary cell walls (PCWs) and secondary cell walls (SCWs), which differ in composition, structure, and purpose. Cellulose in PCWs and SCWs is chemically identical but has different physical characteristics. During PCW synthesis, multiple dispersed CSCs move along a shared linear track in opposing directions while synthesizing cellulose microfibrils with low aggregation. In contrast, during SCW synthesis, we observed swaths of densely arranged CSCs that moved in the same direction along tracks while synthesizing cellulose microfibrils that became highly aggregated. Our data support a model in which distinct spatiotemporal features of active CSCs during PCW and SCW synthesis contribute to the formation of cellulose with distinct structure and organization in PCWs and SCWs of Arabidopsis thaliana This study provides a foundation for understanding differences in the formation, structure, and organization of cellulose in PCWs and SCWs.


Assuntos
Parede Celular/enzimologia , Celulose/biossíntese , Glucosiltransferases/genética , Complexos Multiproteicos/química , Arabidopsis/enzimologia , Arabidopsis/genética , Membrana Celular/química , Membrana Celular/enzimologia , Parede Celular/genética , Celulose/química , Regulação da Expressão Gênica de Plantas , Glucosiltransferases/química , Microfibrilas/química , Microfibrilas/genética , Complexos Multiproteicos/genética
20.
Sci China Life Sci ; 59(2): 206-12, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26803305

RESUMO

Our previous study demonstrated that WLIM1a has dual roles in fiber elongation and secondary cell wall synthesis in upland cotton, and the protein acts either as an actin-binding protein or as a transcription factor. Because WLIM1a consists of two different LIM domains, it is possible that these elements contribute differentially to the dual functions of the protein. In this study, we dissected the two LIM domains and characterized their biochemical functions. By using red fluorescent protein (RFP) fusion, co-sedimentation, and DNA binding methods, we found that the two domains of WLIM1a, domain1 (D1) and domain2 (D2), possessed different biochemical properties. While D1 contributed primarily to the actin filament-bundling activity of WLIM1a, D2 contributed to the DNA-binding activity of the protein; both D1 and D2 relied on a linker sequence for their activities. In addition, we found that WLIM1a and its two LIM domains form dimers in vitro. These results may lead to a better understanding of the molecular mechanisms of dual functions of WLIM1a during cotton fiber development.


Assuntos
Gossypium/metabolismo , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Fibra de Algodão , Dimerização , Dados de Sequência Molecular , Proteínas de Plantas/química , Homologia de Sequência de Aminoácidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...