Over-expression of OsASR confers drought tolerance in rice

Rice (Oryza sativa L.), a staple food for more than half of the global population; being as a paddy crop is particularly susceptible to water stress which reduces its yield drastically. Thus, developing strategies which would help in developing rice variety that can grow even in water deficit condition can be beneficial for increasing crop yield as well as increasing probability of agriculture in drought-prone areas. Abscisic acid stress-ripening proteins (ASR) are a family of plant-specific small hydrophilic proteins encoded by an abiotic stress-regulated gene. The expression of OsASR is strongly induced under the application of drought, salt and abscisic acid (ABA). To provide evidence on the biological role of OsASR proteins against drought, we generated transgenic lines of rice overexpressing OsASR. The extent of tolerance to drought stress of these plants correlated well with the level of OsASR expression. Various biochemical and physiological analyses like malondialdehyde content, proline, ROS scavenging enzymes, electrolyte leakage and histochemical analyses for H₂O₂  and O₂^2- radical showed differential activities during drought tolerance in T3 generation of transgenic lines as compared to wild-type (Wt) plants. In addition, transcriptome analysis revealed that OsASR regulates the expression of a wide spectrum of stress-related genes in response to abiotic stresses through an ABA-dependent regulation pathway. In addition, few genes that are possible OsASR speci?c target genes were identi?ed based on the comparison of the expression pro?les in the transgenic line and the Wt plant and validated through qRT-PCR analysis. These results demonstrate, OsASR to be a positive regulator commonly involved in the tolerance to drought stress in rice and its simple manipulation has great potential with regard to plant improvement.
Take Away Notes:
• Our current approach of manipulating OsASR expression in Rice may be developed as a valuable tool for improving the drought tolerance of agronomically important crop plants.
• This research provides useful information that supports biotechnology applications and molecular breeding that leads to improved drought tolerance in various plants.
• In addition, OsAsR can be transformed into other staple food crop for farming in drought prone area of the world