The R-R-Type MYB-Like Transcription Factor, AtMYBL, is Involved in Promoting Leaf Senescence and Modulates an Abiotic Stress Response in Arabidopsis

Abstract

Functional analysis of a putative novel transcription factor Arabidopsis MYB-like protein designated AtMYBL, which contains two predicted DNA-binding domains, was performed. The physiological role of the R-R-type MYB-like transcription factor has not been reported in any plant. Analyses of an AtMYBL promoter-β-glucuronidase (GUS) construct revealed substantial gene expression in old leaves and induction of GUS activity by ABA and salt stress. AtMYBL-overexpressing plants displayed a markedly enhanced leaf senescence phenotype. Moreover, the ectopic expression of the AtMYBL gene was very significantly influential in senescence parameters including Chl content, membrane ion leakage and the expression of senescence-related genes. Although the seed germination rate was improved under ABA and saline stress conditions in the AtMYBL-overexpressing plants, decreased salt tolerance was evident compared with the wild type and atmybl RNA interference lines during later seedling growth when exposed to long-term salt stress, indicating that AtMYBL protein is able to developmentally regulate stress sensitivity. Furthermore, AtMYBL protein activated the transcription of a reporter gene in yeast. Green fluorescent protein-tagged AtMYBL was localized in the nuclei of transgenic Arabidopsis cells. Taken together, these results suggest that AtMYBL functions in the leaf senescence process, with the abiotic stress response implicated as a putative potential transcription factor.

A Novel Hydrolase Identified by Genomic-Proteomic Analysis of Phenylurea Herbicide Mineralization by Variovorax sp. Strain SRS16

“…strain WDL1 (6). Up-and downregulation of membrane proteins have been previously associated with a stress response (60,62). As discussed by Breugelmans et al (6), linuron exposure appears to induce a stress situation in Variovorax.…”

MYB transcription factor genes as regulators for plant responses: an overview

“…The putative protein (AtMyb2) encoded by AtMYB2 has 274 amino acids, a molecular mass of 32 kDa and a putative DNA binding domain that shows considerable homology to plant MYB-related proteins, such as maize C1. In addition to this, Zhang et al (2011) reported that AtMYBL functions in the leaf senescence process, and thus modulates an abiotic stress response in Arabidopsis.…”

Response to Long-Term NaHCO3-Derived Alkalinity in Model Lotus japonicus Ecotypes Gifu B-129 and Miyakojima MG-20: Transcriptomic Profiling and Physiological Characterization

“…In contrast, several probe sets putatively related to ABA and ethylene biosynthesis were induced in Gifu B-129 roots, where the down-regulation of genes probably involved in auxin and cytokinin response or biosynthesis was also observed. In Arabidopsis , the expression of the senescence-related AtMYBL TF was induced by ABA [74]. In turn, the overexpression of AtMYBL increased the levels of the Senescence-related gene 1 ( SRG1 ), which was reported to increase in senescent organs and hence, it was proposed as a marker for senescence in that model plant [75].…”