N^+注入选育高毒力球孢白僵菌菌株及对3种油茶害虫的毒力测定

Mutation Breeding of a High Virulence Beauveria bassaana Strain by N^+ Implantation and Its Virulence against the Pests of Camellia oleifera

以低能氮离子注入(N+)作为诱变手段对球孢白僵菌进行诱变,并对3种油茶主要害虫进行了毒力测试。结果表明:不同剂量的氮离子注入后白僵菌存活率呈"马鞍曲线",其峰值即150×1013ions.cm-2为诱变最佳剂量。氮离子注入对白僵菌的菌落形态、产孢量、孢子萌发率等生长特性均有影响,通过产孢量、Pr1蛋白酶活和几丁质酶活指标筛选我们得到3株优良菌株,其中BbⅢ22菌株的Pr1蛋白酶活和几丁质酶活分别达0.230、0.137(OD值),为出发菌株的近2倍水平。BbⅢ22菌株对油茶叶蜂、油茶毒蛾有较强的致病力,在孢子浓度为107孢子.mL-1时,致死率达到了80%以上,而对油茶象甲的致死率相对较弱为60%左右。对油茶叶蜂、油茶毒蛾和油茶象甲的LD50对数浓度分别为5.2960、5.6347、6.3555。

In this study, Beauveria bassiana was mutagenized by low energy N＋ implantation, and bioassays were carried out on 3 main pests of Camellia oleifera. The results showed that, by implanting different doses of N＋, the curve of survival rate of B. bassiana showed the typical ＂saddle shape＂. The peak value 150×10^13 ions.cm-2 was the optimal dose of the mutagenic breeding. The growth characteristics as colony morphology, sporulation, spore germination rate of B. bassiana had been effected by N~ implantation. 3 stains of B. bassiana were selected by sporulation, chitinase and Prl enzyme activity as the screening indices, in which the activity of Prl enzyme and chitinase in BbⅢ22 was up to 0.230 and 0.137 （OD value）, which was almost 2 times of the original strain. The strain of BbⅢ22 was the most virulent to the Caliroa camellia Zhou et Huang and Euproctis pseudoconspersa （Strand）, the mortality reached over 80% with concentration of 107 sporesmL-1, whereas the mortality against Curculio chinensis was only around 60%. The logarithmic LDso of the mutant strain against the C. camellia, E. pseudoconspersa and C. chinensis were 5.2960, 5.6347, 6.3555, respectively.