CMYB1 Encoding a MYB Transcriptional Activator Is Involved in Abiotic Stress and Circadian Rhythm in Rice

Through analysis of cold-induced transcriptome, a novel gene encoding a putative MYB transcription factor was isolated and designated Cold induced MYB 1 (CMYB1). Tissue-specific gene expression analysis revealed that CMYB1 was highly expressed in rice stems and nodes. qRT-PCR assay indicated that CMYB1 was dramatically induced by cold stress (>100-folds) and induced by exogenous ABA and osmotic stress. Interestingly, CMYB1 showed rhythmic expression profile in rice leaves at different developmental stages. Subcellular localization assay suggested that CMYB1-GFP (green fluorescent protein) fusion protein was localized in the nuclei. Moreover, CMYB1 exhibited the transcriptional activation activity when transiently expressed in rice protoplast cells. Taken together, CMYB1 probably functions as a transcriptional activator in mediating stress and rhythm responsive gene expression in rice.