关键词: 毛葡萄, 芪合酶基因, 白藜芦醇, 抗病性, 白粉病

Abstract: Vitis quinquangularis‘Danfeng-2’is an important research material with high resistance to powdery mildew due to its high resveratrol content. In the present study，two stilbene synthase genes VqSTS12 and VqSTS25 were obtained from‘Danfeng-2’leaves using homologous sequence cloning. The overexpression vector was constructed and the transgenic seedlings were obtained by Agrobacteriummediated transformation with meristematic bulks of Vitis vinifera‘Thompson Seedless’was used as the receptor material. Through genetic transformation，we finally obtained 7 and 5 transgenic seedlings of VqSTS12 and VqSTS25 respectively，which were confirmed by PCR at DNA level and Western Blot at protein level. Afterwards，the expression of genes related to resveratrol synthesis in transgenic‘Thompson Seedless’seedlings was analyzed by real-time quantitative PCR，which revealed that the expression of stilbene synthase（STS）gene and downstream resveratrol glycosyltransferase（RSGT）gene were up-regulated，while that of chalcone synthase（CHS）gene was down-regulated due to the substrate competition with STS. Meanwhile，the content of stilbene components was higher in transgenic‘Thompson Seedless’seedlings compared to that in wild-type seedlings by HPLC，mainly existing in the form of trans-piceid. The transgenic plants with high content of stilbene components were subsequently selected for the functional study. As a result，the transgenic‘Thompson Seedless’seedlings were obviously less sensitive to powdery mildew than wild-type seedlings. The occurrence of powdery mildew on the transgenic‘Thompson Seedless’seedlings was later and milder compared with non-transgenic seedlings. In detail，a number of powdery mildew spore germination were inhibited，with slow mycelial growth. Moreover，the expression level of VqSTS12 and VqSTS25 genes in transgenic seedlings were significantly increased after induction by powdery mildew. The expression level of STS genes increased rapidly at 1–3 day after inoculation，then decreased，but still remaining at a high level. Finally，the expression level of STS genes rose again at 6–7 day after inoculation. Additionally，we also detected the high content and high activity of resveratrol，piceid，pterostilbene and ε-viniferin in transgenic‘Thompson Seedless’seedlings after inoculation by powdery mildew. In conclusion，these present findings suggested that the stilbene synthetase genes VqSTS12 and VqSTS25 from the Vitis quinquangularis‘Danfeng-2’and their expressed stilbene components exerted certain effects on inhibiting powdery mildew.

Key words: Vitis quinquangularis, stilbene synthase gene, resveratrol, disease-resistance, powdery mildew