OsHSP 17.9, a Small Heat Shock Protein, Confers Improved Productivity and Tolerance to High Temperature and Salinity in a Natural Paddy Field in Transgenic Rice Plants

Various abiotic stress factors, such as high temperatures and salinity, have a significant impact on the development and growth of crop plants and ultimately impact crop yield. Previous studies have reported that overexpression of heat-shock-protein (HSP) genes in transgenic plants can enhance stress tolerance under controlled conditions in laboratories and greenhouses. Despite the significance of multiple environmental stressors on plants in natural paddy fields, there is still a lack of research regarding the contribution of HSP genes to stress tolerance and crop yield. In this study, we cloned and characterized the function of OsHSP 17.9, an HSP gene from Oryza sativa, in rice plants grown under diverse conditions. Our results showed that overexpressing OsHSP 17.9 in rice plants enhanced the activity of antioxidant enzymes under high-temperature and salinity stresses. Moreover, transgenic rice plants overexpressing OsHSP 17.9 exhibited significantly improved adaptability after transplantation from greenhouses to natural paddy fields. In particular, OsHSP 17.9-overexpressing transgenic rice plants established improved agronomic traits and increased grain yields even under unfavorable natural-paddy-field conditions. These results suggest that OsHSP 17.9 transgenic plants can be a promising strategy for cultivating crops in adverse environmental conditions.