Abstract
It is well known that genes involved in a certain biosynthetic pathway are expressed coordinately. By coexpression analysis, we attempted to identify the function of unknown glycosyltransferase genes related in flavonoid metabolism.
In Arabidopsis, flavonoids are highly modified by glycosylation. The structures imply that at least eight glycosyltransferases (GT) are involved in this pathway and only four genes were identified. GTs are encoded by 119 genes in Arabidopsis. Their primary structures are not sufficient to estimate their functions.
By coexpression analysis of public database, ATTED, we found a GT gene that is highly correlated with flavonoid biosynthetic genes. The amino acid sequence is similar to that of flavonol-7-glucosyltransferase. The T-DNA insertion mutants didn't contain flavonoid 7-rhamnosides. These results show that the gene encodes flavonoid-7-rhamnosyltransferase (At7RhaT). Real time PCR analysis showed that transcripts of At7RhaT are accumulated abundantly in buds. It's consistent with the flavonoid accumulation pattern in Arabidopsis organs.
