Abstract:Dunnia sinensis is a rare and endangered plant unique to Guangdong Province. It has white metaseptic calyx segments with obvious veins and has good ornamental value. However, there is no genomic information about it. In order to understand the molecular regulation of calyx development and explore related functional genes, the expression of RNA-seq and differential genes in sepals, fruits, leaves and petals of D. sinensis were analyzed, to screening the specific expression genes or signaling pathways in sepals. The results showed that there were 3 972 differentially expressed genes in sepals compared with leaves, which were mainly concentrated in metabolic pathways, secondary metabolic biosynthesis, photosynthesis, phenyl-C biosynthesis, etc. Compared with petals, there were 9 680 differentially expressed genes (3 616 up-regulated, 6 024 down-regulated, FC>2) in sepals, which were mainly concentrated in plant hormones, phenyl-C biosynthesis, plant pathogen interaction, secondary metabolic biosynthesis and other pathways. Compared with fruit, there were 4 655 differentially expressed genes (1 827 up-regulated, 2 828 down-regulated, FC>2) in sepals, and the enrichment and regulation pathways of differential gene were similar to those of petal transcriptome. Cluster analysis showed that there were three types of transcription factors involved in the development of sepals with specific high expression: ERFs, MYBs and WRKYs. Among them, DsTMYB3 of the MYB family might be involved in the color regulation of sepals. Analysis of highly expressed genes in tissues showed that UBI11 promoter was widely expressed in all tissues, while CSLG2 promoter were specifically expressed in calyx, and the promoters of these genes would be used as genetic tools to drive the targeted genome forming expression or specific expression in calyx. Therefore, some of differentially expressed genes between calyx and the other tissues of D. sinensis, might be involved in the color regulation of sepals, which would provide a basis for the genetic transformation and functional study of D. sinensis.
