Dissecting the Molecular Function of Family Members Under Heat Stress.

STI/HOP functions as a co-chaperone of HSP90 and HSP70 whose molecular function has largely been being restricted as an adaptor protein. However, its role in thermotolerance is not well explored. In this article, we have identified six members of the family, which were named according to their distribution on group 2 and group 6 chromosomes. Interestingly, members were found to express higher as compared to members under heat stress conditions, with being one of the most heat-responsive member. Consistent with this, the heterologous expression of in resulted in enhanced basal as well as acquired thermotolerance as revealed by the higher yield of the plants under stress conditions. Similarly in the case of rice, transgenics exhibited enhanced thermal tolerance. Moreover, we demonstrate that TaSTI-2A interacts with TaHSP90 not only in the nucleus but also in the ER and Golgi bodies, which has not been shown till now. Additionally, TaHSP70 was also found to interact with TaSTI-6D specifically in the cytosol. Thus, these data together suggested that the family members might play different roles under heat stress conditions in order to fine-tune the heat stress response in plants.