盾壳霉抗杀菌剂vinclozolin的诱变及突变体的生防潜力

Mutants of Coniothyrium minitans Tolerant to Vinclozolin and Their Evaluation for Biocontrol Potential

采用适应性培养的方法获得了4个抗杀菌剂vinclozolin的盾壳霉突变体。vinclozolin对野生型盾壳霉菌株Chy-1菌丝生长和分生孢子萌发的EC50分别为1.1和140.0μg/ml;而对突变菌株SV-5-1、SV-5-2、SV-10-1和V-250-1菌丝生长的EC50分别为2219.1、2683.9、2222.8和2504.2μg/ml,对分生孢子萌发的EC50分别是710.4、866.0、931.3和609.3μg/ml。在没有杀菌剂存在的情况下,这些突变菌株的转代培养后代和感染核盘菌菌核后产生的分生孢子后代仍具有抗性。用突变菌株与野生菌株接种核盘菌菌核时,突变菌株的大多数接种处理的菌核被寄生率和菌核腐烂指数与野生菌株接种处理没有明显差异。除菌株V-250-1外,其它3个突变菌株在至少1个接种处理的菌核上产生分生孢子的能力显著高于野生菌株或无明显差异。突变菌株与野生菌株在油菜花瓣上对核盘菌子囊孢子侵染油菜叶片具有明显抑制作用。

Four mutants of the mycoparasite Coniothyrium minitans tolerant to the fungicide vinclozolin were obtained by incubation of mycelia or conidia of the fungus on vinclozolin-amended media. The effective concentration （EC50） for the wild type isolate Chy-1 of C. minitans was 1.1 μg/ml for mycelial growth and 140.0 μg/ml for conidial germination, whereas for the mutants SV-5-1, SV-5-2, SV-10-1 and V-250-1, the EC50 values were 2219.1, 2683.9, 2222.8, and 2504.2 μg/ml , respectively, for the mycelial growth, and 710.4, 866.0, 931.3, and 609.3 μg/ml, respectively, for conidial germination. The fungicide tolerance of these mutants were genetically stable, as progenies of the successive transfers of these mutants and 30 conidial progenies of each mutant isolated from infected sclerotia of Sclerotinia sclerotiorum were as tolerant to vinclozolin as each parental mutant. There were no significant differences （P 〉 0.05） between the four mutants and Chy-1 in infection of sclerotia of S. sclerotiorum in most of the inoculation treatments. The conidial production on infected sclerotia by the mutants SV-5- 1, SV-5-2, and SV-10-1 were as high as or higher than that by Chy-1 for at least one treatment with these mutants. The mutants SV-5-1, SV-5-2 and SV-10-1 were effective in suppression of the infection of rapeseed leaves by ascospores of S. sclerotiorum. This study suggests that four vinclozolin-tolerant mutants of C. minitans were genetically stable, and it is possible to use the fungicide tolerance marker to monitor the survival of this fungus in soil or on plants, and to combine C. minitans with vinclozolin for integrated control of sclcrotinia diseases.