Functional Characterization of , a Critical Rate-Limiting Enzyme, for Turpentine Biosynthesis in Masson Pine ( Lamb.).

As one of the largest and most diverse classes of specialized metabolites in plants, terpenoids (oprenoid compounds, a type of bio-based material) are widely used in the fields of medicine and light chemical products. They are the most important secondary metabolites in coniferous species and play an important role in the defense system of conifers. Terpene synthesis can be promoted by regulating the expressions of terpene synthase genes, and the terpene biosynthesis pathway has basically been clarified in , in which there are multiple rate-limiting enzymes and the rate-limiting steps are difficult to determine, so the terpene synthase gene regulation mechanism has become a hot spot in research. Herein, we amplified a gene (GenBank accession no. MK969119.1) of the MEP pathway (methyl-erythritol 4-phosphate) from . The DXR enzyme activity and chlorophyll a, chlorophyll b and carotenoid contents of overexpressed showed positive regulation. The gene promoter was a tissue-specific promoter and can respond to ABA, MeJA and GA stresses to drive the expression of the reporter gene in . The DXR enzyme was identified as a key rate-limiting enzyme in the MEP pathway and an effective target for terpene synthesis regulation in coniferous species, which can further lay the theoretical foundation for the molecularly assisted selection of high-yielding lipid germplasm of , as well as provide help in the pathogenesis of pine wood nematode disease.