Project description:Crassulacean acid metabolism (CAM) is a water-use efficient adaptation of photosynthesis that has evolved independently many times in diverse lineages of flowering plants. We hypothesize that convergent evolution of protein sequence and temporal gene expression underpins the independent emergences of CAM from C3 photosynthesis. To test this hypothesis, we generated a de novo genome assembly and genome-wide transcript expression data for Kalanchoe fedtschenkoi, an obligate CAM species within the core eudicots with a relatively small genome (~260 Mb). Our comparative analyses identified signatures of convergence in protein sequence and re-scheduling of diel transcript expression of genes involved in nocturnal CO2 fixation, stomatal movement, heat tolerance, circadian clock and carbohydrate metabolism in K. fedtschenkoi and other CAM species in comparison with non-CAM species. These findings provide new insights into molecular convergence and building blocks of CAM and will facilitate CAM-into-C3 photosynthesis engineering to enhance water-use efficiency in crops.
Project description:The sequence determinants of chromatin bivalency remain unclear. We analysed sequence determinants of chromatin bivalency genome-wide in several mammalian species and performed a series of transgenic experiments in mouse ES cells. Genome-wide mapping of H3K27me3 in rat ES cells and ChIP-seq with anti-Ezh2 antibody in transgenic mouse ES cells