陕西省烟草灰霉病病原及云芝多糖对其防治研究

采用形态学观察和分子鉴定方法对2011年在陕西省发生的一种烟草未知病害的病原菌进行鉴定。从病叶组织分离纯化得到病原菌,通过致病性测定以及人工接种后再分离病菌,证明编号LJL007的菌株为该病的致病菌。依据病原菌的形态学和培养特征,将菌株LJL007鉴定为灰葡萄孢Botrytis cinerea Pers.,其有性型为富氏葡萄孢盘菌Botryotinia fuckeliana Whetzel。通过核糖体DNAITS序列分析,分离菌株LJL007序列(登录号:HM17900)与富氏葡萄孢盘菌序列(登录号:HM849615)同源性达100%,进一步证明该病原菌是灰葡萄孢Botrytis cinerea。云芝多糖在离体条件下,对灰葡萄孢的菌丝生长和孢子萌发均无直接抑制作用。云芝多糖对烟草灰霉病有较好预防保护作用,其预防效果可达56.29%。云芝多糖可显著提高烟草体内几丁质酶和β-1,3-葡聚糖酶活性,其活性峰值分别比对照提高56.89%和429.83%,说明云芝多糖可诱导植物产生抗病性。

Causal agent of tobacco gray mould in Shaanxi Province and preventive effects of Trametes versicolor polysaccharides on the disease

Based on morphological characters and molecular data, the pathogenic fungus of an unknown tobacco disease in Shaanxi Province in 2011 was identified. The suspected pathogen was isolated from diseased leaves of tobacco plants, and after pathogenicity tests and re-isolation of the pathogen, the strain LJL007 was determined to be responsible for the disease. The strain LJL007 was identified as Botrytis cinerea, whose teleomorph is Botryotinia fuckeliana on basis of morphological and cultural characters. We found that the sequences of the isolate LJL007 (Accession no.: HM17900) was 100% identical to that of B. fuckeliana (Accession no.: HM849615) by analyzing sequences of the ITS regions of ribosomal DNA, further confirming that the pathogen was Botrytis cinerea. Trametes versicolor polysaccharides cannot inhibit the mycelium growth and spore germination of Botrytis cinerea on potato dextrose agar. However, the polysaccharides had relatively good preventive effects on tobacco gray mould in the field, preventive effectiveness was 56.29%. The results of enzyme activity tests showed that Trametes versicolor polysaccharides significantly enhanced activities of chitinase and β-1,3-glucanase in the tobacco plants after treatment, the peak values of them increased by 56.89% and 429.83% as compared to the control treatment (treatment A: only spraying stilled water on the tobacco) respectively. These results indicated that Trametes versicolor polysaccharides could induce and improve resistance of tobacco plants to gray mould.