Comparative Transcriptomics of Thermotolerance in Arabidopsis and Boechera

The sessile nature of plants presents a number of challenges that plants must overcome. Heat stress is a one of the most significant of these challenges for both crop and native plant species. The ability to survive in high heat is called thermotolerance. This is a complex trait that has many components. Our lab has been studying comparative thermotolerance in Arabidopsis thaliana and its relative Boechera. We have conducted studies with four different Boechera species that are native to California. In our work we have examined both chlorophyll fluorescence and gene expression during and after heat stress. Our studies have indicated that the Boechera species are all more thermotolerant than is Arabidopsis. Analysis of the gene expression of the major heat shock genes using qPCR has shown that the higher thermotolerance in Boechera is not due to higher expression of the heat shock genes in these species when compared to Arabidopsis. Comparative transcriptomics is a powerful tool when used with other measures of plant thermoloterance such as the ability to continue with photosynthesis and organismal response. We have also conducted RNA-seq experiments on both shoot and root tissue that has undergone both acquired and basal heat stress treatments. Our studies indicate that significant differences in gene expression exit between these plants and we discuss these differences in light of our chlorophyll fluorescence data and the differential organismal thermotolerance of Arabidopsis and Boechera.