Effect of spruce PjSTS1a, PjSTS2, or PjSTS3 gene overexpression on stilbene biosynthesis in callus cultures of Vitis amurensis Rupr

Stilbenes are natural compounds protecting plants against microbial pathogens and known to possess valuable biologically active properties. In the present study, we established transgenic grapevine callus cell cultures overexpressing three stilbene synthase (STS) genes of spruce Picea jezoensis PjSTS1a, PjSTS2, and PjSTS3. Transformation of Vitis amurensis calli with the PjSTS1a, PjSTS2, and PjSTS3 genes significantly increased total content of stilbenes in 3.6-6, 2.5-2.9, and 4.1-16.1 times, respectively, in comparison with the control calli. The most pronounced positive effect on the accumulation of stilbenes was observed for the PjSTS3-overexpressing calli where the total content of stilbenes was increased up to 3.1 mg/g DW, and the stilbene production reached 25.4 mg/L. These values were higher than those achieved for the grapevine callus cell cultures overexpressing three STS genes from V. amurensis. Thus, transformation of grapevine cell cultures with spruce STS genes with a relatively low degree of homology to the endogenous VaSTSs is a more effective strategy for induction of plant secondary metabolite biosynthesis than using the grapevine genes for the overexpression experiments.