ANNOUNCEMENTS
High temperature stress, a consequence of global warming has become the foremost vital limiting factors to crop productivity. Increased temperature has cause sessile organisms like plants to avoid or to tolerate these changes. Several mechanisms are involved which helps them to cope up with this stress. For effective crop improvement, it has become important for us to understand the heat stress biology of plants at both phenotypic and genotypic level. In this work, we present the developmental analysis of the Columbia-0 ecotype of Arabidopsis. thaliana which can be used as a reference to unravel the phenotypic differences resulting from genetic variation. Early developmental stages are characterized on vertical plates while the later developmental stages are characterized on the horizontal potting medium. Seedling survival was used as a major criterion for heat tolerance in this study. A heat stress-associated protein (SAP1) was evaluated for its ability to confer heat tolerance on the plant. Accordingly, the gene encoding SAP1 was overexpressed in A. thaliana resulting in two overexpression lines (SAP1-1 and SAP1-2). Transgene presence in the genome was confirmed. SAP1-1 lines were checked for phenotypic difference under control, HS and recovery conditions in comparison to the isogenic parent. Percentage seedling survival was taken as the index of the heat tolerance determining. Investigation of transcript and protein levels revealed differential regulation of SAP1 protein in WT and overexpression mutant under these conditions. Our experiments indicate that alteration in SAP1 levels under normal temperatures did not lead to show any detrimental effects on the growth and development of the plants. In contrast, at high temperatures, the percentage seedling survival rate was higher for overexpression line than the WT indicating a significant role of SAP1 in conferring heat tolerance.
Keywords: Heat stress, Arabidopsis thaliana, abiotic stress, overexpression line, stress-associated protein 1 (SAP1).
