Isolation of a novel MYB transcription factor OsMyb1R from rice and analysis of the response of this gene to abiotic stresses
To understand mechanisms underlying stress responses and discover new stress-tolerance genes in rice (Oryza sativa L.), we analyzed a global genome expression profiling of the indica cultivar Pei’ai 64S subjected to cold, drought, or heat stresses. Expression profiles were obtained for leaf and panicle tissues at seedling, booting and heading stages from plants under no stress, or cold, drought or heat stresses using the GeneChip Rice Genome Array (Affymetrix) representing 51 279 transcripts from japonica and indica rice. A large number of genes highly up- regulated or down-regulated were identified under the stresses. One of these genes, OsMyb1R, was highly induced in leaf and panicle at the heading and flowering stages, in response to all stresses. The expression profile of OsMyb1R obtained by the microarray analysis was confirmed by quantitative real-time reverse transcriptaseplolymerase chain reaction (RT-PCR) analysis of the gene. The two sets of data matched very well, suggesting that OsMyb1R is a multiple stresses responsive gene in rice. In order to study its function in stress tolerance, we cloned the cDNA of the gene through amplification by RT-PCR. Sequence analysis showed that the cDNA encodes a protein of 489 amino acid residues with molecular weight (M.W.) ≈ 56 kD and pI ≈ 6. Bioinformatics analysis revealed that the protein contains a conservative domain of the MYB family gene. Analysis of the putative promoter region for candidate cis-regulatory elements identified 5 matches to cis-elements related to stress responses. Based on the earlier mentioned analysis and results obtained, we propose that OsMyb1R is a novel candidate gene involved in stress tolerance in rice.
Key words: Oryza sativa L., stress, microarray, real-time PCR, MYB, bioinformatics.