Characterization and Function of the 1-Deoxy-D-xylose-5-Phosphate Synthase (DXS) Gene Related to Terpenoid Synthesis in Pinus massoniana

In the methyl-D-erythritol-4-phosphate (MEP) pathway, 1-deoxy-D-xylose-5-phosphate synthase (DXS) is considered the key enzyme for the biosynthesis of terpenoids. In this study, PmDXS (MK970590) was isolated from Pinus massoniana. Bioinformatics analysis revealed homology of MK970590 with DXS proteins from other species. Relative expression analysis suggested that PmDXS expression was higher in roots than in other plant parts, and the treatment of P. massoniana seedlings with mechanical injury via 15% polyethylene glycol 6000, 10 mM H(2)O(2), 50 μM ethephon (ETH), 10 mM methyl jasmonate (MeJA), and 1 mM salicylic acid (SA) resulted in an increased expression of PmDXS. pET28a-PmDXS was expressed in Escherichia coli TransB (DE3) cells, and stress analysis showed that the recombinant protein was involved in resistance to NaCl and drought stresses. The subcellular localization of PmDXS was in the chloroplast. We also cloned a full-length 1024 bp PmDXS promoter. GUS expression was observed in Nicotiana benthamiana roots, stems, and leaves. PmDXS overexpression significantly increased carotenoid, chlorophyll a, and chlorophyll b contents and DXS enzyme activity, suggesting that DXS is important in isoprenoid biosynthesis. This study provides a theoretical basis for molecular breeding for terpene synthesis regulation and resistance.