Isolation and functional characterization of a β-eudesmol synthase, a new sesquiterpene synthase from Zingiber zerumbet Smith

In this paper, we have identified a new sesquiterpene synthase gene (ZSS2) from Zingiber zerumbet Smith. Functional expression of ZSS2 in Escherichia coli and in vitro enzyme assay showed that the encoded enzyme catalyzed the formation of β-eudesmol and five additional by-products. Quantitative RT-PCR analysis revealed that ZSS2 transcript accumulation in rhizomes has strong seasonal variations. To further confirm the enzyme activity of ZSS2 and to assess the potential for metabolic engineering of β-eudesmol production, we introduced a gene cluster encoding six enzymes of the mevalonate pathway into E. coli and coexpressed it with ZSS2. When supplemented with mevalonate, the engineered E. coli produced a similar sesquiterpene profile to that produced in the in vitro enzyme assay, and the yield of β-eudesmol reached 100 mg/L.