Transcriptome profiling for drought tolerant and susceptible cultivars of indica rice

Traditional rice varieties found in India have many desirable characteristics. Amongst them, their differential responses to abiotic and biotic stresses are of great agricultural importance. Drought or osmotic stress is one of the major abiotic stresses afflicting crop plants in India. Indigenous varieties like Dagad deshi have been found to be drought resistant and, thereby, are being studied in great detail by plant breeders and biotechnologists alike. In this study, we have analyzed the transciptomes of two contrasting cultivars, i.e. Dagad deshi (tolerant) and IR20 (susceptible), under control and stress conditions to elucidate the differences in their responses to drought stress using Affymetrix microarray platform. Hydroponically grown seven-day-old seedlings of Dagad deshi and IR20 were subjected to drought stress by placing them on 3 mm Whatmann sheets under light for 3 h and 6 h at 28±1oC. For control samples, seedlings were kept in RGM (root growth medium) for 6 h at 28±1oC. RNA extracted from each sample was hybridized on rice Affymetrix microarrays. Three biological replicates of each sample were used for microarray analysis. Overall, eighteen samples were analyzed representing control, 3 h and 6 h of dehydration stress for each cultivar (Dagad deshi and IR20).