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The plant-specific SR45 protein negatively regulates glucose and ABA signaling during early seedling development in Arabidopsis.
Carvalho, Raquel Fonseca; Carvalho, Sofia Domingues; Duque, Paula.
Afiliação
  • Carvalho RF; Instituto Gulbenkian de Ciência, Oeiras, Portugal.
Plant Physiol ; 154(2): 772-83, 2010 Oct.
Article em En | MEDLINE | ID: mdl-20699397
ABSTRACT
The plant-specific SR45 belongs to the highly conserved family of serine/arginine-rich (SR) proteins, which play key roles in precursor-mRNA splicing and other aspects of RNA metabolism. An Arabidopsis (Arabidopsis thaliana) loss-of-function mutant, sr45-1, displays pleiotropic phenotypes, such as defects in flower and leaf morphology, root growth, and flowering time. Here, we show that the sr45-1 mutation confers hypersensitivity to glucose (Glc) during early seedling growth in Arabidopsis. Unlike wild-type plants, the sr45-1 mutant displays impaired cotyledon greening and expansion as well as reduced hypocotyl elongation of dark-grown seedlings when grown in the presence of low (3%) Glc concentrations. In addition, SR45 is involved in the control of Glc-responsive gene expression, as the mutant displays enhanced repression of photosynthetic and nitrogen metabolism genes and overinduction of starch and anthocyanin biosynthesis genes. Like many other sugar response mutants, sr45-1 also shows hypersensitivity to abscisic acid (ABA) but appears to be unaffected in ethylene signaling. Importantly, the sr45-1 mutant shows enhanced ability to accumulate ABA in response to Glc, and the ABA biosynthesis inhibitor fluridone partially rescues the sugar-mediated growth arrest. Moreover, three ABA biosynthesis genes and two key ABA signaling genes, ABI3 and ABI5, are markedly overinduced by Glc in sr45-1. These results provide evidence that the SR45 protein defines a novel player in plant sugar response that negatively regulates Glc signaling during early seedling development by down-regulating both Glc-specific ABA accumulation and ABA biosynthesis and signaling gene expression.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Proteínas de Transporte / Arabidopsis / Ácido Abscísico / Proteínas de Arabidopsis / Plântula / Glucose Idioma: En Ano de publicação: 2010 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Proteínas de Transporte / Arabidopsis / Ácido Abscísico / Proteínas de Arabidopsis / Plântula / Glucose Idioma: En Ano de publicação: 2010 Tipo de documento: Article