葡萄霜霉病菌离体保存方法的研究

Research on the Plasmopara viticola Preservation Technology

【目的】葡萄霜霉病菌(Plasmopara viticola(Berk.&Curt.)Berl.&de Toni)是一种专性寄生菌,不能在人工培养基上培养和保存,故探索其较长时间的保存方法,对其生物学特性和发病规律的研究具有重要作用。【方法】研究5%二甲基亚砜低温冷冻保存、带菌叶片液氮冷冻低温保存、带菌叶片直接低温冷冻保存以及20%甘油和5%二甲基亚砜+5%脱脂牛乳五种方法在不同低温条件下保存不同时间对孢子囊致病性的影响。【结果】在五种方法中,以带菌叶片液氮-72℃低温保存效果最好,360 d后用其孢子囊接种,其发病面积百分率为21.2%以上,仍具有较高的致病性;其次为用5%二甲基亚砜-72℃低温冷冻保存和带菌叶片直接-72℃保存,360 d后接种,其发病面积百分率分别为6.2%和3.6%,保存效果明显不如前者。【结论】五种方法中,以带菌叶片液氮冷冻低温保存方法较好,在-72℃条件下,可以保持该菌孢子囊的致病性360 d以上。

【Objective】Plasmopara viticola( Berk. & Curt.) Berl. & de Toni is an obligate parasitic fungus. Up to now it can not be preserved on culture medium. The characteristics of grape downy mildew fungus affect the research progress of its biology and disease regularity. Just for this,we carried out this study.【Method】In this study,the sporangia of P. viticola were preserved in protective substances of 5% dimethyl sulfoxide,5% dimethyl sulfoxide plus 5% skim milk and 20% glycerol under the condition of different low temperature and preservation different time. The leaves infected by grape downy mildew were frozen in nitrogen liquid and then placed in frozen storage conditions. The infected leaves were immediately placed in low temperature.【Result】The results showed that the sporangia preserved at- 72℃ were the best and after 360 days they were infected by grape downy mildew frozen in nitrogen liquid and then placed in frozen storage conditions,and these sporangia remained virulent to grape leaves by more then 21. 2%.【Conclusion】In the five methods,the leaves infected by grape downy mildew frozen in nitrogen liquid were the best and placed in-72℃ frozen storage conditions,they could keep the pathogenicity of the sporangium for more than 360 days.