MOLECULAR CLONING, EXPRESSION, AND CHARACTERIZATION OF THE CDNA AND GENE FOR SESQUITERPENE CYCLASE IN POTATO

摘要

Sesquiterpene cyclase and squalene synthase are key branch point enzymes in isoprenoid pathway for the synthesis of sesquiterpenoid phytoalexins and sterols/steroid glycoalkaloids, respectively. cDNA and genome clones encoding sesquiterpene cyclase were isolated from potato cDNA and genomic libraries, respectively. A phylogenetic tree showed that the sesquiterpene cyclase is vetispiradiene synthase. Infection of Phytophthora infestans with potato tubers caused transient increases in the transcript level of vetispiradiene synthase in a compatible and an incompatible interactions. On the other hand, wound-induced expression of the squalene synthase was suppressed in favor of the expression of vetispiradiene synthase regardless of inoculated races.