Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros

Base de dados
Ano de publicação
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Plant Physiol ; 172(3): 1772-1786, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27663411

RESUMO

In flowering plants, successful male reproduction requires the sophisticated interaction between somatic anther wall layers and reproductive cells. Timely degradation of the innermost tissue of the anther wall layer, the tapetal layer, is critical for pollen development. Ca2+ is a well-known stimulus for plant development, but whether it plays a role in affecting male reproduction remains elusive. Here we report a role of Defective in Exine Formation 1 (OsDEX1) in rice (Oryza sativa), a Ca2+ binding protein, in regulating rice tapetal cell degradation and pollen formation. In osdex1 anthers, tapetal cell degeneration is delayed and degradation of the callose wall surrounding the microspores is compromised, leading to aborted pollen formation and complete male sterility. OsDEX1 is expressed in tapetal cells and microspores during early anther development. Recombinant OsDEX1 is able to bind Ca2+ and regulate Ca2+ homeostasis in vitro, and osdex1 exhibited disturbed Ca2+ homeostasis in tapetal cells. Phylogenetic analysis suggested that OsDEX1 may have a conserved function in binding Ca2+ in flowering plants, and genetic complementation of pollen wall defects of an Arabidopsis (Arabidopsis thaliana) dex1 mutant confirmed its evolutionary conservation in pollen development. Collectively, these findings suggest that OsDEX1 plays a fundamental role in the development of tapetal cells and pollen formation, possibly via modulating the Ca2+ homeostasis during pollen development.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Oryza/anatomia & histologia , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Pólen/crescimento & desenvolvimento , Pólen/metabolismo , Morte Celular , Clonagem Molecular , Fragmentação do DNA , Regulação da Expressão Gênica de Plantas , Homeostase , Modelos Biológicos , Mutação/genética , Oryza/genética , Oryza/ultraestrutura , Fenótipo , Filogenia , Plantas Geneticamente Modificadas , Pólen/citologia , Pólen/ultraestrutura , Proteínas Recombinantes/metabolismo
2.
Plant Physiol ; 158(3): 1279-92, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22247272

RESUMO

The accumulation of a number of small RNAs in plants is affected by abscisic acid (ABA) and abiotic stresses, but the underlying mechanisms are poorly understood. The miR168-mediated feedback regulatory loop regulates ARGONAUTE1 (AGO1) homeostasis, which is crucial for gene expression modulation and plant development. Here, we reveal a transcriptional regulatory mechanism by which MIR168 controls AGO1 homeostasis during ABA treatment and abiotic stress responses in Arabidopsis (Arabidopsis thaliana). Plants overexpressing MIR168a and the AGO1 loss-of-function mutant ago1-27 display ABA hypersensitivity and drought tolerance, while the mir168a-2 mutant shows ABA hyposensitivity and drought hypersensitivity. Both the precursor and mature miR168 were induced under ABA and several abiotic stress treatments, but no obvious decrease for the target of miR168, AGO1, was shown under the same conditions. However, promoter activity analysis indicated that AGO1 transcription activity was increased under ABA and drought treatments, suggesting that transcriptional elevation of MIR168a is required for maintaining a stable AGO1 transcript level during the stress response. Furthermore, we showed both in vitro and in vivo that the transcription of MIR168a is directly regulated by four abscisic acid-responsive element (ABRE) binding factors, which bind to the ABRE cis-element within the MIR168a promoter. This ABRE motif is also found in the promoter of MIR168a homologs in diverse plant species. Our findings suggest that transcriptional regulation of miR168 and posttranscriptional control of AGO1 homeostasis may play an important and conserved role in stress response and signal transduction in plants.


Assuntos
Ácido Abscísico/farmacologia , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas Argonautas/metabolismo , MicroRNAs/metabolismo , RNA de Plantas/metabolismo , Adaptação Fisiológica , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Proteínas Argonautas/genética , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Sequência Conservada , Secas , Regulação da Expressão Gênica de Plantas , Homeostase , MicroRNAs/genética , Motivos de Nucleotídeos , Regiões Promotoras Genéticas , RNA de Plantas/genética , Transdução de Sinais , Estresse Fisiológico , Ativação Transcricional
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA