淡紫拟青霉航天诱变菌株对南方根结线虫的致病力

Pathogenicity of Aerospace Mutants of Paecilomyces lilacinus against Meloidogyne incognita

[目的]为筛选对南方根结线虫具有高致病力的淡紫拟青霉航天诱变菌株,通过淡紫拟青霉山东寿光菌株搭载神舟八号获得10个淡紫拟青霉航天诱变菌株。[方法]以这10个航天诱变菌株对南方根结线虫卵进行寄生试实验,观察了其发酵液对南方根结线虫卵及二龄幼虫的作用,并对与毒力相关的胞外酶几丁质酶和蛋白酶活性进行了测定。在此基础上,通过盆钵试验方法,检验菌株Sd-m-9、Sd-m-16和Sd-m-26对花椒南方根结线虫的防治效果。[结果]结果表明:10个诱变菌株对南方根结线虫卵的寄生率与原始菌株存在分化,其中有3个诱变菌株的寄生率增强,即Sd-m-9、Sd-m-16和Sd-m-26;这10个诱变菌株的几丁质酶和蛋白质酶的活性与对南方根结线虫卵的寄生率之间呈正相关。在盆钵试验中,菌株Sd-m-9、Sd-m-16和Sd-m-26对南方根结线虫的根结指数较原始菌株下降88.34%89.70%。[结论]因此,航天诱变菌株Sd-m-9、Sd-m-16和Sd-m-26可用于对南方根结线虫的防治。

[Objective] To select some highly pathogenic strains in the aerospace mutants of Paecilomyces lilacinus obtained from its original strain Sd carried by the Shenzhou-8 spacecraft as biological control agents against southern root-knot nematodes Meloidogyne incognita. [Method]Their pathogenicity against M. incognita was evaluated by comparing their hyphal parasitizing rates on nematode eggs,inhibiting effect of their fermentation broths on egg hatching and juveniles. Their activities of such enzymes as protease and chitinase were also investigated. Based on these results,three optimum mutants（ Sd-m-9,Sd-m-16 and Sd-m-26） were adopted for pot bioassay against M.incognita on pepper seedlings. [Results]The mutants Sd-m-9,Sd-m-16 and Sd-m-26 possessed the most evident virulence against M. incognita than the original strain Sd. Analysis of the relationships between the activities of protease,chitinase of aerospace mutants and parasitic rates indicated that the parasitic rate was significantly and positively correlated with the activities of protease and chitinase. The pot experiment of pepper seedlings planted in autoclaved soil showed that strains Sd-m-9,Sd-m-16 and Sd-m-26 were more effective for controlling M. incognita,the root-knot index was reduced by 88. 34% 89. 70% as compared with that of the original strain Sd. [Conclusion]It is suggest that the aerospace mutants Sd-m-9,Sd-m-16 and Sd-m-26 are of application potential for biological control of M. incognita.