Faculty of Agriculture, University of Guilan, Rasht, Iran.
Rice plants are injured at the seedling stage in early spring in northern Iran. In order to study rice response to cold stress, the expression of OsDREB1A, OsAP37, OsMYB3R-2, and OsNAC6 genes encoding transcription factors was observed in 14-day-old seedlings of cold-tolerant genotype PR and cold-sensitive cv. Hashemi during cold stress (5°C for 24 h) using the differential display method and three replications for each genotype. PCR products were quantified using Total Lab (ver. 1.10) software and significant differences in gene expression were found using Wilcoxon Test of SPSS (ver. 18) software. Transcription factors play an important regulatory role in the response to abiotic stress and interact with cis-elements in the promoter regions of several stress related genes. Different genes displayed different expression patterns in tolerant and susceptible plants during cold stress. While the expression level of OsNAC6 gene increased in both genotypes after cold stress, the expression level of OsDREB1A, OsAP37, and OsMYB3R-2 genes upregulated significantly in PR and decreased in the Hashemi genotype. Results suggest that the expression of genes encoding transcription factors changes in response to cold stress and so could be an informative resource in breeding and biotechnology projects aimed at developing cold tolerance in rice.