Bupleurum chinense Transcriptome or Gene expression

Bupleurum chinense DC. is a widely used traditional Chinese medicinal plant species with saikosaponins as the main active components. A one-quarter 454 pyrosequencing run were conducted and produced a total of 195,088 high quality reads with an average read length of 356 bases. De novo assembly generated 24,037 unique sequences containing 22,748 contigs and 1,289 singletons. A total of 12,649 (52.6%) unique sequences were annotated by a BLAST similarity search (E-value = 1e-10) against three public databases, KEGG (10,277, 42.8%), Nr (10,409, 43.3%) and Uniprot (9,453, 39.3%). With respect to the genes related to the saikosaponins biosynthesis, those ESTs were found which encode the known enzymes catalyzing the formation of saikosaponins backbone. Additionally, a total of 246 cytochrome P450 (P450) and 102 glycosyltransferase unique sequences were found in our present 454 data set. The full length cDNAs of 7 P450s and 7 UGTs were verified by RT-PCR or cloned using 5'' and/or 3'' RACE methods. According to the coordinate expression up-regulation with ß-AS in the methyl jasmonate (MeJA) treated adventitious roots and their expression profiles in various tissues of B. chinense, two P450s and Three UGTs were most likely to be the candidates involved in saikosaponins biosynthesis. Our results demonstrate the candidate genes for enzymes involved in saikosaponins biosynthesis, especially for the P450s and UGTs, which provide a substantial foundation for the follow-up researches on the metabolism and regulation of saikosaponins.