High temperature and UV-C treatments affect stilbenoid accumulation and related gene expression levels in Gnetum parvifolium

Abstract

Background: Gnetum parvifolium stems and roots have long been used in traditional Chinese medicines. Stilbenes are bioactive compounds present in G. parvifolium plants, and possess antioxidative and anticancer properties. However, little is known about the responses of G. parvifolium stilbene biosynthetic pathways to stress conditions. Therefore, we investigated stilbene biosynthesis, including the expression of relevant genes, in the plant exposed to high-temperature and ultraviolet-C treatments.

Results: High temperatures did not influence the accumulation of total stilbenes in stems, but decreased stilbene concentrations in roots at 3 h, with a subsequent restoration to control levels. In contrast, ultraviolet irradiation induced the accumulation of total stilbenes in stems, but not in roots. We also observed that high temperatures inhibited the production of resveratrol and piceatannol in stems and roots, while ultraviolet treatments initially inhibited their accumulation (up to 6 h), but induced their production at later time points. Analyses of specific genes (i.e., PAL, C4H, 4CL, STS, and CYP) revealed their expression levels generally increased in stress-treated stems and roots, although there was some variability in the expression profiles during treatments.

Conclusions: Our results indicated that high temperatures and ultraviolet irradiation differentially affect the biosynthesis of specific stilbenes in G. parvifolium stems and roots. Therefore, cultivating G. parvifolium seedlings under optimal stress conditions may increase the biosynthesis of specific stilbene compounds.