Molecular Cloning, Characterization, and Functional Analysis of Acetyl-CoA C-Acetyltransferase and Mevalonate Kinase Genes Involved in Terpene Trilactone Biosynthesis from Ginkgo biloba.

Ginkgolides and bilobalide, collectively termed terpene trilactones (TTLs), are terpenoids that form the main active substance of . Terpenoids in the mevalonate (MVA) biosynthetic pathway include acetyl-CoA -acetyltransferase (AACT) and mevalonate kinase (MVK) as core enzymes. In this study, two full-length (cDNAs) encoding AACT (, GenBank Accession No. KX904942) and MVK (, GenBank Accession No. KX904944) were cloned from . The deduced GbAACT and GbMVK proteins contain 404 and 396 amino acids with the corresponding open-reading frame (ORF) sizes of 1215 bp and 1194 bp, respectively. Tissue expression pattern analysis revealed that was highly expressed in ginkgo fruits and leaves, and was highly expressed in leaves and roots. The functional complementation of in AACT-deficient strain and in MVK-deficient strain confirmed that mediated the conversion of mevalonate acetyl-CoA to acetoacetyl-CoA and mediated the conversion of mevalonate to mevalonate phosphate. This observation indicated that and are functional genes in the cytosolic mevalonate (MVA) biosynthesis pathway. After seedlings were treated with methyl jasmonate and salicylic acid, the expression levels of and increased, and TTL production was enhanced. The cloning, characterization, expression and functional analysis of and will be helpful to understand more about the role of these two genes involved in TTL biosynthesis.