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1.
Plant Cell ; 31(2): 520-536, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30651348

RESUMO

The apoplast serves as the first battlefield between the plant hosts and invading microbes; therefore, work on plant-pathogen interactions has increasingly focused on apoplastic immunity. In this study, we identified three proteins in the apoplast of cotton (Gossypium sp) root cells during interaction of the plant with the fungal pathogen Verticillium dahliae Among these proteins, cotton host cells secrete chitinase 28 (Chi28) and the Cys-rich repeat protein 1 (CRR1), while the pathogen releases the protease VdSSEP1. Biochemical analysis demonstrated that VdSSEP1 hydrolyzed Chi28, but CRR1 protected Chi28 from cleavage by Verticillium dahliae secretory Ser protease 1 (VdSSEP1). In accordance with the in vitro results, CRR1 interacted with Chi28 in yeast and plant cells and attenuated the observed decrease in Chi28 level that occurred in the apoplast of plant cells upon pathogen attack. Knockdown of CRR1 or Chi28 in cotton plants resulted in higher susceptibility to V. dahliae infection, and overexpression of CRR1 increased plant resistance to V dahliae, the fungus Botrytis cinerea, and the oomycete Phytophthora parasitica var nicotianae By contrast, knockout of VdSSEP1 in V. dahliae destroyed the pathogenicity of this fungus. Together, our results provide compelling evidence for a multilayered interplay of factors in cotton apoplastic immunity.


Assuntos
Quitinases/metabolismo , Gossypium/metabolismo , Gossypium/microbiologia , Proteínas de Plantas/metabolismo , Verticillium/patogenicidade , Quitinases/genética , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Gossypium/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética
2.
Plant J ; 95(6): 1055-1068, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29952082

RESUMO

Salicylic acid (SA) signalling plays an essential role in plant innate immunity. In this study, we identified a component in the SA signaling pathway in potato (Solanum tuberosum), the transcription factor StbZIP61, and characterized its function in defence against Phytophthora infestans. Expression of StbZIP61 was induced upon P. infestans infection and following exposure to the defense signaling hormones SA, ethylene and jasmonic acid. Overexpression of StbZIP61 increased the tolerance of potato plants to P. infestans while RNA interference (RNAi) increased susceptibility. Yeast two-hybrid and pull down experiments revealed that StbZIP61 could interact with an NPR3-like protein (StNPR3L) that inhibited its DNA-binding and transcriptional activation activities. Moreover, StNPR3L interacted with StbZIP61 in an SA-dependent manner. Among candidate genes involved in SA-regulated defense responses, StbZIP61 had a significant impact on expression of StICS1, which encodes a key enzyme for SA biosynthesis. StICS1 transcription was induced upon P. infestans infection and this responsive expression to the pathogen was reduced in StbZIP61 RNAi plants. Accordingly, StICS1 expression was remarkably enhanced in StbZIP61-overexpressing plants. Together, our data demonstrate that StbZIP61 functions in concert with StNPR3L to regulate the temporal activation of SA biosynthesis, which contributes to SA-mediated immunity against P. infestans infection in potato.


Assuntos
Phytophthora infestans , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Planta/fisiologia , Proteínas de Plantas/fisiologia , Ácido Salicílico/metabolismo , Solanum tuberosum/microbiologia , Fatores de Transcrição/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/imunologia , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/metabolismo , Interferência de RNA , Solanum tuberosum/imunologia , Solanum tuberosum/metabolismo , Fatores de Transcrição/metabolismo , Técnicas do Sistema de Duplo-Híbrido
3.
Autophagy ; 14(4): 598-618, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29369001

RESUMO

The mechanisms underlying the functional link between autophagy and plant innate immunity remain largely unknown. In this study, we investigated the autophagy-mediated plant defense responses against Verticillium dahliae (V. dahliae) infection by comparative proteomics and cellular analyses. An assessment of the autophagy activity and disease development showed that autophagic processes were tightly related to the tolerance of Arabidopsis plant to Verticillium wilt. An isobaric tags for relative and absolute quantification (iTRAQ)-based proteomics analysis was performed, and we identified a total of 780 differentially accumulated proteins (DAPs) between wild-type and mutant atg10-1 Arabidopsis plants upon V. dahliae infection, of which, 193 ATG8-family-interacting proteins were identified in silico and their associations with autophagy were verified for several selected proteins. Three important aspects of autophagy-mediated defense against V. dahliae infection were revealed: 1) autophagy is required for the activation of upstream defense responses; 2) autophagy-mediated mitochondrial degradation (mitophagy) occurs and is an important player in the defense process; and 3) autophagy promotes the transdifferentiation of perivascular cells and the formation of xylem hyperplasia, which are crucial for protection against this vascular disease. Together, our results provide several novel insights for understanding the functional association between autophagy and plant immune responses.


Assuntos
Arabidopsis/imunologia , Arabidopsis/microbiologia , Autofagia/imunologia , Doenças das Plantas/microbiologia , Verticillium/metabolismo , Regulação da Expressão Gênica de Plantas/imunologia , Proteínas de Plantas/metabolismo , Proteômica/métodos
4.
Plant Sci ; 268: 1-10, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29362078

RESUMO

Accumulating evidence indicates that plant plastocyanin is involved in copper homeostasis, yet the physiological relevance remains elusive. In this study, we found that a plastocyanin gene (SsPETE2) from euhalophyte Suaeda salsa possessed a novel antioxidant function, which was associated with the copper-chelating activity of SsPETE2. In S. salsa, expression of SsPETE2 increased in response to oxidative stress and ectopic expression of SsPETE2 in Arabidopsis enhanced the antioxidant ability of the transgenic plants. SsPETE2 bound Cu ion and alleviated formation of hydroxyl radicals in vitro. Accordingly, SsPETE2 expression lowered the free Cu content that was associated with reduced H2O2 level under oxidative stress. Arabidopsis pete1 and pete2 mutants showed ROS-sensitive phenotypes that could be restored by expression of SsPETE2 or AtPETEs. In addition, SsPETE2-expressing plants exhibited more potent tolerance to oxidative stress than plants overexpressing AtPETEs, likely owing to the stronger copper-binding activity of SsPETE2 than AtPETEs. Taken together, these results demonstrated that plant PETEs play a novel role in oxidative stress tolerance by regulating Cu homeostasis under stress conditions, and SsPETE2, as an efficient copper-chelating PETE, potentially could be used in crop genetic engineering.


Assuntos
Adaptação Fisiológica , Chenopodiaceae/genética , Chenopodiaceae/fisiologia , Expressão Ectópica do Gene , Estresse Oxidativo/genética , Proteínas de Plantas/metabolismo , Plastocianina/genética , Adaptação Fisiológica/efeitos dos fármacos , Antioxidantes/metabolismo , Arabidopsis/genética , Arabidopsis/fisiologia , Quelantes/farmacologia , Chenopodiaceae/efeitos dos fármacos , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Cobre/farmacologia , Desoxirribose/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Peróxido de Hidrogênio/farmacologia , Radical Hidroxila/metabolismo , Íons , Ferro/metabolismo , Simulação de Dinâmica Molecular , Mutação/genética , Estresse Oxidativo/efeitos dos fármacos , Paraquat/farmacologia , Fenótipo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Plastocianina/metabolismo , Transporte Proteico/efeitos dos fármacos
5.
J Integr Plant Biol ; 59(8): 531-534, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28474404

RESUMO

Cell elongation and secondary wall deposition are two consecutive stages during cotton fiber development. The mechanisms controlling the progression of these two developmental phases remain largely unknown. Here, we report the functional characterization of the actin-bundling protein GhFIM2 in cotton fiber. Overexpression of GhFIM2 increased the abundance of actin bundles, which was accompanied with accelerated fiber growth at the fast-elongating stage. Meanwhile, overexpression of GhFIM2 could propel the onset of secondary cell wall biogenesis. These results indicate that the dynamic rearrangement of actin higher structures involving GhFIM2 plays an important role in the development of cotton fiber cells.


Assuntos
Actinas/metabolismo , Fibra de Algodão , Gossypium/metabolismo , Proteínas de Plantas/metabolismo , Parede Celular/metabolismo , Gossypium/citologia , Gossypium/genética , Plantas Geneticamente Modificadas
6.
J Proteomics ; 152: 226-235, 2017 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-27871873

RESUMO

The soil-borne necrotrophic pathogen fungus Rhizoctonia solani is destructive, causing disease in various important crops. To date, little is known about the host defence mechanism in response to invasion of R. solani. Here, an iTRAQ-based proteomic analysis was employed to investigate pathogen-responsive proteins in the disease tolerant/resistant cotton cultivar CRI35. A total of 174 differentially accumulated proteins (DAPs) were identified after inoculation of cotton plants with R. solani. Functional categorization analysis indicated that these DAPs can be divided into 12 subclasses. Notably, a large portion of DAPs are known to function in reactive oxygen species (ROS) metabolism and the expression of several histone-modifying and DNA methylating proteins were significantly induced upon challenge with the fungus, indicating that the redox homeostasis and epigenetic regulation are important for cotton defence against the pathogen. Additionally, the expression of proteins involved in phenylpropanoid biosynthesis was markedly changed in response to pathogen invasion, which may reflect a particular contribution of secondary metabolism in protection against the fungal attack in cotton. Together, our results indicate that the defence response of cotton plants to R. solani infection is active and multifaceted and involves the induction of proteins from various innate immunity-related pathways. SIGNIFICANCE: Cotton damping-off is a destructive disease caused by the necrotrophic fungus Rhizoctonia solani. To date, the host defence mechanism involved in the disease protection remains largely unknown. Here, we reported the first proteomic analysis on cotton immune responses against R. solani infection. Employing iTRAQ technique, we obtained a total of 174 differentially accumulated proteins (DAPs) that can be classified into 12 functional groups. Further analysis indicated that ROS homeostasis, epigenetic regulation and phenylpropanoid biosynthesis were tightly associated with the innate immune responses against R. solani infection in cotton. The obtained data provide not only important information for understanding the molecular mechanism involved in plant-R. solani interaction but also application clues for genetic breeding of crops with improved R. solani resistance.


Assuntos
Gossypium/microbiologia , Interações Hospedeiro-Patógeno/imunologia , Doenças das Plantas/microbiologia , Proteômica/métodos , Rhizoctonia/patogenicidade , Epigênese Genética , Imunidade Inata , Oxirredução
7.
Plant Cell Physiol ; 57(6): 1244-56, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27296714

RESUMO

Grassbur is a destructive and invasive weed in pastures, and its burs can cause gastric damage to animals. The strong adaptability and reproductive potential of grassbur are partly due to a unique germination mechanism whereby twin seeds develop in a single bur: one seed germinates, but the other remains dormant. To investigate the molecular mechanism of seed germination in twin seeds, we used isobaric tags for relative and absolute quantitation (iTRAQ) to perform a dynamic proteomic analysis of germination and dormancy. A total of 1,984 proteins were identified, 161 of which were considered to be differentially accumulated. The differentially accumulated proteins comprised 102 up-regulated and 59 down-regulated proteins. These proteins were grouped into seven functional categories, ribosomal proteins being the predominant group. The authenticity and accuracy of the results were confirmed by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time reverse transcription-PCR (qPCR). A dynamic proteomic analysis revealed that ribosome synthesis and carbohydrate metabolism affect seed germination possibly through the phosphoinositide 3-kinase (PI3K) pathway. As the PI3K pathway is generally activated by insulin, analyses of seeds treated with exogenous insulin by qPCR, ELISA and iTRAQ confirmed that the PI3K pathway can be activated, which suppresses dormancy and promotes germination in twin grassbur seeds. Together, these results show that the PI3K pathway may play roles in stimulating seed germination in grassbur by modulating ribosomal synthesis and carbohydrate metabolism.


Assuntos
Metabolismo dos Carboidratos , Marcação por Isótopo/métodos , Fosfatidilinositol 3-Quinases/metabolismo , Dormência de Plantas , Plantas Daninhas/fisiologia , Proteômica/métodos , Ribossomos/metabolismo , Sementes/metabolismo , Metabolismo dos Carboidratos/efeitos dos fármacos , Ciclo do Ácido Cítrico/efeitos dos fármacos , DNA de Plantas/metabolismo , Metabolismo Energético/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Insulina/farmacologia , Dormência de Plantas/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Plantas Daninhas/efeitos dos fármacos , Plantas Daninhas/enzimologia , Biossíntese de Proteínas/efeitos dos fármacos , RNA de Plantas/metabolismo , Ribossomos/efeitos dos fármacos , Sementes/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
8.
Plant Physiol ; 170(4): 2392-406, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-26869704

RESUMO

Examining the proteins that plants secrete into the apoplast in response to pathogen attack provides crucial information for understanding the molecular mechanisms underlying plant innate immunity. In this study, we analyzed the changes in the root apoplast secretome of the Verticillium wilt-resistant island cotton cv Hai 7124 (Gossypium barbadense) upon infection with Verticillium dahliae Two-dimensional differential gel electrophoresis and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry analysis identified 68 significantly altered spots, corresponding to 49 different proteins. Gene ontology annotation indicated that most of these proteins function in reactive oxygen species (ROS) metabolism and defense response. Of the ROS-related proteins identified, we further characterized a thioredoxin, GbNRX1, which increased in abundance in response to V. dahliae challenge, finding that GbNRX1 functions in apoplastic ROS scavenging after the ROS burst that occurs upon recognition of V. dahliae Silencing of GbNRX1 resulted in defective dissipation of apoplastic ROS, which led to higher ROS accumulation in protoplasts. As a result, the GbNRX1-silenced plants showed reduced wilt resistance, indicating that the initial defense response in the root apoplast requires the antioxidant activity of GbNRX1. Together, our results demonstrate that apoplastic ROS generation and scavenging occur in tandem in response to pathogen attack; also, the rapid balancing of redox to maintain homeostasis after the ROS burst, which involves GbNRX1, is critical for the apoplastic immune response.


Assuntos
Gossypium/metabolismo , Gossypium/microbiologia , Homeostase , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tiorredoxinas/metabolismo , Verticillium/fisiologia , Resistência à Doença , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Especificidade de Órgãos/genética , Filogenia , Raízes de Plantas/metabolismo , Feixe Vascular de Plantas/metabolismo , Proteômica
9.
J Exp Bot ; 67(6): 1935-50, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26873979

RESUMO

Accumulating evidence indicates that plant MYB transcription factors participate in defense against pathogen attack, but their regulatory targets and related signaling processes remain largely unknown. Here, we identified a defense-related MYB gene (GhMYB108) from upland cotton (Gossypium hirsutum) and characterized its functional mechanism. Expression of GhMYB108 in cotton plants was induced by Verticillium dahliae infection and responded to the application of defense signaling molecules, including salicylic acid, jasmonic acid, and ethylene. Knockdown of GhMYB108 expression led to increased susceptibility of cotton plants to V. dahliae, while ecotopic overexpression of GhMYB108 in Arabidopsis thaliana conferred enhanced tolerance to the pathogen. Further analysis demonstrated that GhMYB108 interacted with the calmodulin-like protein GhCML11, and the two proteins form a positive feedback loop to enhance the transcription of GhCML11 in a calcium-dependent manner. Verticillium dahliae infection stimulated Ca(2+) influx into the cytosol in cotton root cells, but this response was disrupted in both GhCML11-silenced plants and GhMYB108-silenced plants in which expression of several calcium signaling-related genes was down-regulated. Taken together, these results indicate that GhMYB108 acts as a positive regulator in defense against V. dahliae infection by interacting with GhCML11. Furthermore, the data also revealed the important roles and synergetic regulation of MYB transcription factor, Ca(2+), and calmodulin in plant immune responses.


Assuntos
Retroalimentação Fisiológica , Gossypium/imunologia , Gossypium/microbiologia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo , Verticillium/fisiologia , Arabidopsis/genética , Cálcio/metabolismo , Sinalização do Cálcio/genética , Núcleo Celular/metabolismo , Citosol/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Gossypium/genética , Doenças das Plantas/genética , Proteínas de Plantas/química , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Ligação Proteica , Domínios Proteicos , Frações Subcelulares/metabolismo , Transativadores/metabolismo , Transcrição Genética
10.
Molecules ; 21(2): 32, 2016 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-26821011

RESUMO

Dihydroflavanol 4-reductase (DFR) is a key later enzyme involved in two polyphenols' (anthocyanins and proanthocyanidins (PAs)) biosynthesis, however it is not characterized in cotton yet. In present reports, a DFR cDNA homolog (designated as GhDFR1) was cloned from developing fibers of upland cotton. Silencing GhDFR1 in cotton by virus-induced gene silencing led to significant decrease in accumulation of anthocyanins and PAs. More interestingly, based on LC-MS analysis, two PA monomers, (-)-epicatachin and (-)-epigallocatachin, remarkably decreased in content in fibers of GhDFR1-silenced plants, but two new monomers, (-)-catachin and (-)-gallocatachin were present compared to the control plants infected with empty vector. The ectopic expression of GhDFR1 in an Arabidopsis TT3 mutant allowed for reconstruction of PAs biosynthesis pathway and led to accumulation of PAs in seed coat. Taken together, these data demonstrate that GhDFR1 contributes to the biosynthesis of anthocyanins and PAs in cotton.


Assuntos
Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Clonagem Molecular/métodos , Gossypium/enzimologia , Antocianinas/biossíntese , Catequina/análogos & derivados , Catequina/análise , Catequina/biossíntese , Fibra de Algodão , Gossypium/genética , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proantocianidinas/biossíntese
11.
Sci Rep ; 5: 10343, 2015 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-26179843

RESUMO

Cotton, an important commercial crop, is cultivated for its natural fibers, and requires an adequate supply of soil nutrients, including phosphorus, for its growth. Soil phosporus exists primarily in insoluble forms. We isolated a mitochondrial malate dehydrogenase (MDH) gene, designated as GhmMDH1, from Gossypium hirsutum L. to assess its effect in enhancing P availability and absorption. An enzyme kinetic assay showed that the recombinant GhmMDH1 possesses the capacity to catalyze the interconversion of oxaloacetate and malate. The malate contents in the roots, leaves and root exudates was significantly higher in GhmMDH1-overexpressing plants and lower in knockdown plants compared with the wild-type control. Knockdown of GhmMDH1 gene resulted in increased respiration rate and reduced biomass whilst overexpression of GhmMDH1 gave rise to decreased respiration rate and higher biomass in the transgenic plants. When cultured in medium containing only insoluble phosphorus, Al-phosphorus, Fe-phosphorus, or Ca-phosphorus, GhmMDH1-overexpressing plants produced significantly longer roots and had a higher biomass and P content than WT plants, however, knockdown plants showed the opposite results for these traits. Collectively, our results show that GhmMDH1 is involved in plant and root growth under phosphorus deficiency conditions in cotton, owing to its functions in leaf respiration and P acquisition.


Assuntos
Genes de Plantas , Gossypium/enzimologia , Malato Desidrogenase/genética , Mitocôndrias/enzimologia , Fósforo/deficiência , Raízes de Plantas/crescimento & desenvolvimento , Biomassa , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Gossypium/genética , Gossypium/crescimento & desenvolvimento , Malato Desidrogenase/metabolismo , Plantas Geneticamente Modificadas , Frações Subcelulares/enzimologia
12.
J Genet Genomics ; 42(6): 311-7, 2015 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-26165497

RESUMO

The transition from the vegetative phase to the reproductive phase is a major developmental process in flowering plants. The underlying mechanism controlling this cellular process remains a research focus in the field of plant molecular biology. In the present work, we identified a gene encoding the C3H2C3-type RING finger protein NtRCP1 from tobacco BY-2 cells. Enzymatic analysis demonstrated that NtRCP1 is a functional E3 ubiquitin ligase. In tobacco plants, expression level of NtRCP1 was higher in the reproductive shoot apices than in the vegetative ones. NtRCP1-overexpressing plants underwent a more rapid transition from the vegetative to the reproductive phase and flowered markedly earlier than the wild-type control. Histological analysis revealed that the shoot apical meristem of NtRCP1-overexpressing plants initiated inflorescence primordia precociously compared to the wild-type plant due to accelerated cell division. Overexpression of NtRCP1 in BY-2 suspension cells promoted cell division, which was a consequence of the shortened G2 phase in the cell cycle. Together, our data suggest that NtRCP1 may act as a regulator of the phase transition, possibly through its role in cell cycle regulation, during vegetative/reproductive development in tobacco plant.


Assuntos
Flores/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Tabaco/genética , Flores/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética
13.
Mol Plant ; 8(3): 399-411, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25704161

RESUMO

In this study, we identified a defense-related major latex protein (MLP) from upland cotton (designated GhMLP28) and investigated its functional mechanism. GhMLP28 transcripts were ubiquitously present in cotton plants, with higher accumulation in the root. Expression of the GhMLP28 gene was induced by Verticillium dahliae inoculation and was responsive to defense signaling molecules, including ethylene, jasmonic acid, and salicylic acid. Knockdown of GhMLP28 expression by virus-induced gene silencing resulted in increased susceptibility of cotton plants to V. dahliae infection, while ectopic overexpression of GhMLP28 in tobacco improved the disease tolerance of the transgenic plants. Further analysis revealed that GhMLP28 interacted with cotton ethylene response factor 6 (GhERF6) and facilitated the binding of GhERF6 to GCC-box element. Transient expression assay demonstrated that GhMLP28 enhanced the transcription factor activity of GhERF6, which led to the augmented expression of some GCC-box genes. GhMLP28 proteins were located in both the nucleus and cytoplasm and their nuclear distribution was dependent on the presence of GhERF6. Collectively, these results demonstrate that GhMLP28 acts as a positive regulator of GhERF6, and synergetic actions of the two proteins may contribute substantially to protection against V. dahliae infection in cotton plants.


Assuntos
Gossypium/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/imunologia , Verticillium/fisiologia , Resistência à Doença , Etilenos/metabolismo , Regulação da Expressão Gênica de Plantas , Gossypium/genética , Gossypium/microbiologia , Doenças das Plantas/imunologia , Proteínas de Plantas/genética , Ácido Salicílico/metabolismo
15.
Plant Cell Physiol ; 55(1): 148-61, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24214268

RESUMO

Examination of aquaporin (AQP) membrane channels in extremophile plants may increase our understanding of plant tolerance to high salt, drought or other conditions. Here, we cloned a tonoplast AQP gene (TsTIP1;2) from the halophyte Thellungiella salsuginea and characterized its biological functions. TsTIP1;2 transcripts accumulate to high levels in several organs, increasing in response to multiple external stimuli. Ectopic overexpression of TsTIP1;2 in Arabidopsis significantly increased plant tolerance to drought, salt and oxidative stresses. TsTIP1;2 had water channel activity when expressed in Xenopus oocytes. TsTIP1;2 was also able to conduct H2O2 molecules into yeast cells in response to oxidative stress. TsTIP1;2 was not permeable to Na(+) in Xenopus oocytes, but it could facilitate the entry of Na(+) ions into plant cell vacuoles by an indirect process under high-salinity conditions. Collectively, these data showed that TsTIP1;2 could mediate the conduction of both H2O and H2O2 across membranes, and may act as a multifunctional contributor to survival of T. salsuginea in highly stressful habitats.


Assuntos
Aquaporinas/metabolismo , Brassicaceae/fisiologia , Estresse Fisiológico , Vacúolos/metabolismo , Animais , Arabidopsis/genética , Arabidopsis/fisiologia , Transporte Biológico/efeitos dos fármacos , Brassicaceae/efeitos dos fármacos , Brassicaceae/genética , Clonagem Molecular , Difusão , Secas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas/genética , Proteínas de Fluorescência Verde/metabolismo , Peróxido de Hidrogênio/metabolismo , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/metabolismo , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Filogenia , Plantas Geneticamente Modificadas , Transporte Proteico/efeitos dos fármacos , Sódio/metabolismo , Cloreto de Sódio/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Frações Subcelulares/efeitos dos fármacos , Frações Subcelulares/metabolismo , Vacúolos/efeitos dos fármacos , Água/metabolismo , Xenopus
16.
Plant Cell ; 25(11): 4421-38, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24220634

RESUMO

LIN-11, Isl1 and MEC-3 (LIM)-domain proteins play pivotal roles in a variety of cellular processes in animals, but plant LIM functions remain largely unexplored. Here, we demonstrate dual roles of the WLIM1a gene in fiber development in upland cotton (Gossypium hirsutum). WLIM1a is preferentially expressed during the elongation and secondary wall synthesis stages in developing fibers. Overexpression of WLIM1a in cotton led to significant changes in fiber length and secondary wall structure. Compared with the wild type, fibers of WLIM1a-overexpressing plants grew longer and formed a thinner and more compact secondary cell wall, which contributed to improved fiber strength and fineness. Functional studies demonstrated that (1) WLIM1a acts as an actin bundler to facilitate elongation of fiber cells and (2) WLIM1a also functions as a transcription factor to activate expression of Phe ammonia lyase-box genes involved in phenylpropanoid biosynthesis to build up the secondary cell wall. WLIM1a localizes in the cytosol and nucleus and moves into the nucleus in response to hydrogen peroxide. Taken together, these results demonstrate that WLIM1a has dual roles in cotton fiber development, elongation, and secondary wall formation. Moreover, our study shows that lignin/lignin-like phenolics may substantially affect cotton fiber quality; this finding may guide cotton breeding for improved fiber traits.


Assuntos
Parede Celular/metabolismo , Fibra de Algodão , Gossypium/citologia , Gossypium/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Actinas/metabolismo , Núcleo Celular/metabolismo , Parede Celular/genética , Parede Celular/ultraestrutura , Clonagem Molecular , Citoplasma/metabolismo , Regulação da Expressão Gênica de Plantas , Gossypium/efeitos dos fármacos , Gossypium/genética , Peróxido de Hidrogênio/farmacologia , Lignina/metabolismo , Filogenia , Células Vegetais/metabolismo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Transporte Proteico/efeitos dos fármacos
17.
Plant Physiol ; 162(3): 1669-80, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23715527

RESUMO

Plant-specific TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play crucial roles in development, but their functional mechanisms remain largely unknown. Here, we characterized the cellular functions of the class I TCP transcription factor GhTCP14 from upland cotton (Gossypium hirsutum). GhTCP14 is expressed predominantly in fiber cells, especially at the initiation and elongation stages of development, and its expression increased in response to exogenous auxin. Induced heterologous overexpression of GhTCP14 in Arabidopsis (Arabidopsis thaliana) enhanced initiation and elongation of trichomes and root hairs. In addition, root gravitropism was severely affected, similar to mutant of the auxin efflux carrier PIN-FORMED2 (PIN2) gene. Examination of auxin distribution in GhTCP14-expressing Arabidopsis by observation of auxin-responsive reporters revealed substantial alterations in auxin distribution in sepal trichomes and root cortical regions. Consistent with these changes, expression of the auxin uptake carrier AUXIN1 (AUX1) was up-regulated and PIN2 expression was down-regulated in the GhTCP14-expressing plants. The association of GhTCP14 with auxin responses was also evidenced by the enhanced expression of auxin response gene IAA3, a gene in the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) family. Electrophoretic mobility shift assays showed that GhTCP14 bound the promoters of PIN2, IAA3, and AUX1, and transactivation assays indicated that GhTCP14 had transcription activation activity. Taken together, these results demonstrate that GhTCP14 is a dual-function transcription factor able to positively or negatively regulate expression of auxin response and transporter genes, thus potentially acting as a crucial regulator in auxin-mediated differentiation and elongation of cotton fiber cells.


Assuntos
Gossypium/citologia , Gossypium/genética , Ácidos Indolacéticos/metabolismo , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Diferenciação Celular , Núcleo Celular/metabolismo , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Gossypium/metabolismo , Gravitropismo/genética , Dados de Sequência Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Fatores de Transcrição/genética , Tricomas/genética , Tricomas/metabolismo
18.
J Proteomics ; 78: 374-88, 2013 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-23079072

RESUMO

A comparative proteomic analysis was performed to identify the differences between brown cotton fiber and a white near-isogenic line, and 78 differential spots were identified at three time points (12-, 18-, and 24-day post-anthesis [DPA]) using MALDI-TOF/TOF. Our data illustrate several aspects of pigment synthesis and fiber development in brown color fiber (BCF). First, 21 spots were associated with secondary metabolism; 15 of these with high abundance in BCF were involved in flavonoid biosynthesis. Second, several spots with lower abundance in BCF were found. Thirteen spots were related to energy/carbohydrate metabolism; in particular, spots related to the glycolytic pathway exhibited lower abundance in 12 DPA BCF. Several spots related to redox homeostasis, cytoskeleton, and protein metabolism also showed lower abundance in BCF, including proteins that are critical for fiber development, such as ascorbate peroxidase, superoxide dismutase, actin, annexin and heat shock protein. Third, several proteins such as leucine aminopeptidase preprotein and progesterone-5-beta-reductase were newly identified proteins in cotton fibers. These findings demonstrated the presence of a complicated metabolic network in BCF and advanced our understanding of the molecular mechanisms of pigment biosynthesis in colored cotton, which will provide new insight for the development of new color types by genetic manipulation.


Assuntos
Flavonoides/biossíntese , Gossypium/metabolismo , Pigmentos Biológicos/biossíntese , Proteínas de Plantas/metabolismo , Proteômica , Metabolismo dos Carboidratos/fisiologia , Fibra de Algodão , Metabolismo Energético/fisiologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos
19.
J Integr Plant Biol ; 54(6): 412-21, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22583823

RESUMO

AaNhaD, a gene isolated from the soda lake alkaliphile Alkalimonas amylolytica, encodes a Na(+) /H(+) antiporter crucial for the bacterium's resistance to salt/alkali stresses. However, it remains unknown whether this type of bacterial gene may be able to increase the tolerance of flowering plants to salt/alkali stresses. To investigate the use of extremophile genetic resources in higher plants, transgenic tobacco BY-2 cells and plants harboring AaNhaD were generated and their stress tolerance was evaluated. Ectopic expression of AaNhaD enhanced the salt tolerance of the transgenic BY-2 cells in a pH-dependent manner. Compared to wild-type controls, the transgenic cells exhibited increased Na(+) concentrations and pH levels in the vacuoles. Subcellular localization analysis indicated that AaNhaD-GFP fusion proteins were primarily localized in the tonoplasts. Similar to the transgenic BY-2 cells, AaNhaD-overexpressing tobacco plants displayed enhanced stress tolerance when grown in saline-alkali soil. These results indicate that AaNhaD functions as a pH-dependent tonoplast Na(+) /H(+) antiporter in plant cells, thus presenting a new avenue for the genetic improvement of salinity/alkalinity tolerance.


Assuntos
Gammaproteobacteria/genética , Plantas Geneticamente Modificadas/metabolismo , Tolerância ao Sal/genética , Trocadores de Sódio-Hidrogênio/genética , Sódio/metabolismo , Linhagem Celular , Citosol/metabolismo , Concentração de Íons de Hidrogênio , Trocadores de Sódio-Hidrogênio/metabolismo , Tabaco/metabolismo , Vacúolos/metabolismo
20.
Plant Physiol ; 159(2): 835-50, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22492844

RESUMO

The BLADE-ON-PETIOLE (BOP) genes of Arabidopsis (Arabidopsis thaliana) have been shown to play an essential role in floral abscission by specializing the abscission zone (AZ) anatomy. However, the molecular and cellular mechanisms that underlie differentiation of the AZ are largely unknown. In this study, we identified a tobacco (Nicotiana tabacum) homolog of BOP (designated NtBOP2) and characterized its cellular function. In tobacco plants, the NtBOP2 gene is predominantly expressed at the base of the corolla in an ethylene-independent manner. Both antisense suppression of NtBOP genes and overexpression of NtBOP2 in tobacco plants caused a failure in corolla shedding. Histological analysis revealed that the differentiation of the corolla AZ was blocked in the transgenic flowers. This blockage was due to uncontrolled cell elongation at the region corresponding to wild-type AZ. The role of NtBOP2 in regulating cell elongation was further demonstrated in Bright Yellow 2 single cells: perturbation of NtBOP2 function by a dominant negative strategy led to the formation of abnormally elongated cells. Subcellular localization analysis showed that NtBOP2-green fluorescent protein fusion proteins were targeted to both the nucleus and cytoplasm. Yeast two-hybrid, firefly luciferase complementation imaging, and in vitro pull-down assays demonstrated that NtBOP2 proteins interacted with TGA transcription factors. Taken together, these results indicated that NtBOP2 mediated the differentiation of AZ architecture by controlling longitudinal cell growth. Furthermore, NtBOP2 may achieve this outcome through interaction with the TGA transcription factors and via an ethylene-independent signaling pathway.


Assuntos
Diferenciação Celular , Flores/ultraestrutura , Tabaco/genética , Sequência de Aminoácidos , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Crescimento Celular , Núcleo Celular/genética , Núcleo Celular/metabolismo , Cromossomos de Plantas/genética , Cromossomos de Plantas/metabolismo , Citoplasma/genética , Citoplasma/metabolismo , DNA Complementar/genética , DNA Complementar/metabolismo , Flores/genética , Flores/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Microscopia Eletrônica , Dados de Sequência Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/citologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais , Tabaco/citologia , Tabaco/fisiologia , Técnicas do Sistema de Duplo-Híbrido
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