Combined elicitation of chitosan and ultraviolet C enhanced stilbene production and expression of chitinase and β-1,3-glucanase in Vitis vinifera cell suspension cultures

Cell suspension cultures of Vitis vinifera were treated with chitosan and ultraviolet C (UV-C) irradiation, alone or in combination, to investigate the relationship between the production of stilbene and the transcript profiles of genes encoding the enzymes involved in stilbene synthesis. Treatment at the proper concentration or dosage enhanced both stilbene production inside the cells and trans-resveratrol accumulation in the culture medium without loss of biomass, and the combined treatment was the most efficient. Total intracellular stilbene content was markedly increased by the joint use of chitosan and UV-C, reaching the maximum at 60 h (1945.91 ± 70.73 μg g⁻¹ DW; 207.23 % higher than in untreated cells) after elicitation. When cell cultures were supplemented with both elicitors, we observed a synergistic effect on the accumulation of trans-resveratrol release into the culture medium with the maximal concentration of 3.05 ± 0.17 mg l⁻¹ at 60 h. Total phenolics and total flavonoids contents were also highly increased after elicitations. The expression levels of genes associated with stilbene biosynthesis were significantly up-regulated in response to the two elicitors, and the combined elicitation showed a synergistic effect on the expression of stilbene synthase. Furthermore, the expression levels and enzyme activities of two pathogenesis-related proteins, chitinase and β-1,3-glucanase, increased after treatment. The results suggest that the combined treatment of chitosan and UV-C irradiation can significantly enhance the production of stilbene in V. vinifera cell cultures and may induce defense response by increasing the expression and activity levels of chitinase and β-1,3-glucanase.