The Mutation Breeding By N~+Implantation In Beauveria Bassiana And Detection On The Virulence Against Pests Of Camellia Oleifera

As an entomopathogenic fungus, Beauveria bassiana (Bals.)Vuillemin includes a large number of candidate strains that have been developed into formulation for use in arthropod pest control worldwide. With the excessive using of chemical pesticides and the problem of "3R" is worsening, B. bassiana as one of the major biocontrol agents to combat pests, more and more attention should be taken in the production and application.Low energy ion implantation is a high-tech mutation breeding technique invented by China scholars first time in1980s. Ion beam has a effect of energy deposition, momentum transfer and strong ionization to the organisms, while indirect injury is produced by high-reactive radicals. Induced the base biochemical changes of chromosome structure variation cell in physiology, genetic material. Low energy ion implantation is a new, efficient, convenient, safe and pollution-free mutagenic source, and has the characteristics of broad mutation spectrum, light damage, stable mutation rate.Camellia oleifera originated from China can be found in18provinces or municipalities in the south of China, especially in the south of the Hunan province. Moreover, it should be kept in mind that the tea-oil (Camellia oleifera oil) is an edible oil of high quality comprising much oleic acid, unsaturated fatty acids and monounsaturated fatty acids and regarding as one of the four primary edible tree oils. More than100inscets and mites are associated with Camellia oleifera in China, attacking various parts like root, stem, leaf and bud. Of this, Dasmithius camellia, Euproctis pseudoconspersa and Curculio chinensis commonly known as key pests, has been causing appreciable damage to tea-oil plantation in China for several decades. The caterpillar feeds mainly on tender leaves and makes them skeletonised. And Beauveria bassiana as a biological control is a major strategy in Integrated Pest Management (IPM) system. The information from this study is needed for ananalyzing and directing the B. bassiana effectively in boiogical control of Camellia oleifera bugs.In this study, Beauveria bassiana was mutagenized using low energy N+implantation, by implanting different doses of N+, the curve of survival rate of Beauveria bassiana took a typical "saddle shape". The optimal dose of the mutagenic breeding was the value of the peak area of the curve, which was150X1013ions·cm-2. N+implantation affects Beauveria bassiana on the growth characteristics as colony morphology, sporulation, spore germination rate. The strains' spore output, chitinase activity and Pr1enzyme activity were selected as the indices for screening, the result showed that3stains was excellent on these indexes, in which the activity of Chitinase and Pr1enzyme in BbⅢ22was up to0.230and0.137(OD value), almost2times of the original strain.The virulence of3different stains of Beauveryia bassiana named BbⅢ05,BbⅢ22, BbⅢ28against adult, D. camellia, E. pseudoconspersa and C. chinensis was tested in laboratory. The strains Beauveria bassiana to the Dasmithius camellia and Euproctis pseudoconspersa under the concentration of107spores·mL-1causing a corrected mortality of80%, And causing a corrected mortality of60%to Curculio chinensis. The strains BbⅢ22was most virulent. Its logarithmic concentration of the LD50and95%confidence intervals to the Dasmithius camellia, Euproctis pseudoconspersa and Curculio chinensis were5.2960(4.7925-5.6194),5.6347(5.2125-6.0091),6.3555(5.6925-7.1509). The results indicate that Beauveria bassiana were effective in prevention and control of pests of C. oleifera.The fermentation conditions for Beauveria bassiana BbⅢ22were optimized. At first,the optimal matrix formula, corn flour concentration, water contentration, inoculation, fermentation temperature and fermentation time were determined by single factor experiments. The experiment used Box-Behnken experimental design and response surface analytical methodology to optimum fermentation conditions were obtained:corn flour8.22g·L-1, water content38%, inoculation10.5%,temperature25.7℃. Under these conditions, the sporulation of BbⅢ22was10.578(×1010spores·g-1), being increased by3times compare with before optimization.