Expression Analysis of Transcription Factors and Related Genes Induced by Water Stress in Contrasting Genotypes of Rice (Oryza Sativa L.)

Abstract

Rice (Oryza sativa L.) is one of most important cereal crops that supplies staple food for more tham half of the world’s population. Rice consumes more water and often encounters moisture defict stress during different growth stages that lead to huge loss in productivity. We chose twelve aromatic and basmati rice varieties along with two rice varieties, Nagina-22 (drought resistant) and IR-64 (drought sensitive). To check stage specific expression, we studied the data in-silico at three stages namely seedling, vegetative and reproductive stage under well watered (control) and water abiotic stress conditions. Present study focused to identify changes in morphological, physiological, biochemical and gene expression level under field conditions at reproductive stage under water stress. Statistical analysis revealed significant differences between Nagina-22 and IR-64 in RWC, MSI, chlorophyll a, chlorophyll b, total chlorophyll, proline, catalase, and peroxidise at reproductive growth stage of rice. The mean value of all parameters decreases significantly during drought stress at reproductive growth stages except for proline, catalase, peroxidise that showed remarkable elevation change during stress at reproductive stage in Nagina-22. In-silico analysis of microarray and RNA sequence pertaining to gene expression revealed large number of water stress responsive genes which were filtered according to needs of present investigation. Gene expression analysis of selected genes confirmed that genes are expresses differentially at different stages under stress and control conditions. Based on finding of this study, we conclude that although Nagina-22 performed better than IR-64 and other aromatic rice genotypes at reproductive stage under water stress environment. Therefore, it is suggested that interrogation of field studies for morphological, physiological, biochemical, in-silico and transcript abundance of important transcription factors and their stage specific expression pattern is an important prerequisite information to be integrated in genetic improvement of drought tolerance in aromatic rice