CLONING AND EXPRESSION ANALYSIS OF JcAACT, JcMDC AND JcFPS, INVOLVED IN TERPENOID BIOSYNTHESIS IN JATROPHA CURCAS L.

To better understand the functions of key genes involved in terpenoid biosynthesis in Jatropha curcas, we cloned and characterized three genes, namely acetyl CoA acyltransferase (JcAACT), diphosphate mevalonate decarboxylase (JcMDC) and famesyl pyrophosphate synthase (JcFPS). The opening reading frames (ORFs) of JcAACT, JcMDC and JcFPS were 1239 bp,1248 bp and 1029 bp, respectively, encoding a 412-amino acid, 415-amino acid and 342-amino acid polypeptide, respectively. Results of homology analysis showed that JcAACT, JcMDC and JcFPS encoded proteins that all had the highest identity and closest relationship with the corresponding genes in Hevea brasiliensis, with identities of 89%, 92% and 93%, respectively. JcAACT, JcMDC and JcFPS were expressed in all organs tested of J. curcas, the highest expression level for each gene occurred in seeds. In the early growth stage of seeds, the expression level of each of these three genes increased with time, with JcAACT and JcMDC expression level reaching a peak at the late stage of seed development (50 d), while JcFPS expression level reached a peak at the mid-late stage (40 d). Following the peak, the expression of each gene then declined. The expression level of JcAACT was the highest of the three genes, regardless of the organ or the stage of seed growth, indicating its important role in J. curcas. This study lays the foundation for a better understanding of the important role of the JcAACT, JcMDC and JcFPS genesin the terpenoid biosynthesis pathway of J. curcas.