Cloning, E-coli expression and molecular analysis of a novel sesquiterpene synthase gene from Artemisia annua

A 1 886 bp full-length sesquiterpene synthase (AaSES) cDNA was cloned front a high-yield Artemisia annua L. strain 001 by a rapid amplification of cDNA end (RACE) strategy. AaSES is 59% identical to Artemisia cyclase cDNA clone cASC125, 50% identical to epi-cedrol synthase from A. annua , 48% identical to amorpha-4, 11-diene synthase from A. annua, 39% identical to the 5-epi-aristolechene synthase from tabacco, 38 % identical to vetispiradiene synthase front H. muticus, 41 % identical to the, delta-cadinene synthase from cotton. The coding region of the cDNA was inserted into a procaryotic expression vector pET-30a and overexpressed in E. coli BL21 ( DE3). The cyclase proteins extracted front bacterial culture were found largely in an insoluble protein fraction. AaSES expresses in leaves, stems a-rid flowers, not in roots as indicated by Northern blotting analysis.