Expression analysis of five critical transcription factors (TFs) OsbHLH148, OsbZIP72, OsMYB2, OsNAC6 and TRAB1 in response to drought stress in contrasting Iranian rice genotypes

Abstract

Drought stress causes great damage to the rice cultivation all over the world. Specific transcription factors (TFs) can regulate the expression of stress-related genes. In this research, we investigated the effect of drought stress on the expression of five specific transcription factors OsbHLH148, OsbZIP72, OsMYB2, OsNAC6 and TRAB1 at vegetative and reproductive stages in two Iranian rice cultivars with drought-sensitive and tolerant backgrounds; Hashemi and Neda. Using a real-time quantitative PCR (qPCR) approach, this study revealed that the expression of OsbZIP72, OsMYB2 and OsNAC6 were increased significantly in the Hashemi cultivar under drought stress at the vegetative stage. It seems that these three genes paly their roles in the drought sensitive cultivar Hashemi at the vegetative stage and do not play any role at the reproductive stage as the most sensitive stage to drought stress. The expression of TRAB1 was increased in Hashemi cultivar at the reproductive stage, while the expression of TRAB1 was decreased in Neda cultivar at the vegetative stage. This indicates that the expression of TRAB1 could respond sensitively to drought stress at the vegetative stage. Furthermore, there were statistically significant increases in expression of OsbHLH148, OsbZIP72, OsMYB2, OsNAC6 and TRAB1 in Neda (tolerant) cultivar at the reproductive stage. Therefore, our study suggests that these five genes might be involved in drought tolerance of this cultivar to drought stress at the reproductive stage. Thus, they could be used as viable candidate TFs to develop additional varieties of drought-tolerant transgenic rice.