一株与类酵母共生菌拮抗的放线菌的筛选及其活性成分对褐飞虱的防治效果

Screening an actinomycete antagonist against yeast-like symbiotics and the effect of its active ingredient on Nilaparvata lugens

【目的】为减少吡虫啉的使用,开发以褐飞虱Nilaparvata lugens体内的类酵母共生菌(Yeast-like symbiontes,YLS)为靶标的杀菌剂,并与之配伍使用,以探索防治褐飞虱的一种可行策略。【方法】以季也蒙毕赤酵母Pichiaguilliermondii为靶标菌,从土壤样品中筛选到一株对季也蒙毕赤酵母具有较强拮抗活性的放线菌,分离纯化其活性化合物并进行化合物结构解析,并通过单独或与吡虫啉配伍使用,研究其对褐飞虱的防治效果。【结果】经鉴定,该菌株命名为白色链霉菌Streptomyces albus 2013;S.albus 2013发酵液中主要的活性成分为四霉素A(Tetramycin A)。褐飞虱取食分别用浓度为500 mg/L和750 mg/L的四霉素A喷施稻苗后,褐飞虱体内季也蒙毕赤酵母的数量分别降低至3.1 copies/L和1.2 copies/L,显著(P<0.05)低于对照组(4.5 copies/L)。将吡虫啉与不同浓度的四霉素A进行配伍使用后发现:与单独使用吡虫啉对照相比,10 mg/L 80%吡虫啉与浓度为500 mg/L和750 mg/L的四霉素A按1∶1等体积配伍,褐飞虱的死亡率均有所提高,分别为50.3%和59.4%。【结论】筛选的拮抗菌株S.albus 2013的活性成分四霉素A与吡虫啉配伍不仅能提高褐飞虱的防治效果,而且可降低吡虫啉的使用量。这一结果为研发新型褐飞虱生物防治策略提供了思路。

[Objectives]To reduce the use of imidacloprid by developing a bactericide that targets yeast-like symbiontes(YLS)in Nilaparvata lugens and is compatible with imidacloprid.[Methods]An antagonistic actinomycete was isolated from a soil sample using Pichia guilliermondii as the indicator strain and its active ingredient purified and analyzed.The effectiveness of the active ingredient for controlling N.lugens,both alone,and in combination with imidacloprid,was determined.[Results]The actinomycete,named Streptomyces albus 2013,displayed a high level of antagonistic activity against P.guilliermondii.The major bioactive ingredient of S.albus 2013 was identified as tetramycin A.Treating rice seedlings with 500 mg/L or 750 mg/L tetramycin A significantly reduced the number of P.guilliermondii in N.lugens feeding on these plants to 3.1 copies/L and 1.2 copies/L,respectively,compared to the control group which had 4.5 copies/L.The mortality rates of N.lugens treated with a mixture of 500 mg/L imidacloprid and 750 mg/L tetramycin A(1︰1,v/v),were 50.3%and 59.4%higher than that of those treated with the same concentration of imidacloprid alone.[Conclusion]A combination of imidacloprid and tetramycin A isolated from a strain of S.albus 2013 not only increased mortality of N.lugens but also reduced imidacloprid usage.These findings provide a novel strategy for controlling N.lugens.