Glycosylation machinery responsible for the biosynthesis of plant aroma glycosides

Abstract

Plants have the ability to synthesize and emit a diversity of volatile organic compounds （VOCs） that may act as aroma and flavor molecules in response to insect herbivores, mechanical wounding, and attraction of pollinators.　Plants also have the capacity to accumulate the VOCs into plant itself.　Several plant species morphologically develop specialized glandular trichomes to store VOCs which are released in response to tissue damage for chemical defense such as inhibiting microbial growth or deterring herbivores.　Glycosylation is another machinery for safely storing VOCs into normal cells.　Tea plant （Camellia sinensis） stores VOCs with glycosylation in tea leaves, mainly conjugated to β-primeverosides, the most abundant form of aroma diglycosides in C. sinensis.　Here, we introduced two UDP-glycosyltransferases （UGTs） from C. sinensis, UGT85K11 （CsGT1） and UGT94P1 （CsGT2）, converting VOCs into β-primeverosides by sequential glucosylation and xylosylation, respectively.　This information can be used to preserve tea aroma better during the manufacturing process and to investigate the mechanism of plant chemical defenses.