Fatal attraction: Engineering and selecting beauveria bassiana fungal strains for targeted biocontrol of Mountain Pine Beetle (Dendroctonus ponderosae)

在不列颠哥伦比亚省1600万公顷的土地上，山松甲虫（Dendroctonus ponderosae）已经杀死了50%的成熟黑松（Pinus contorta）。它现在已经越过落基山脉进入阿尔伯塔省，在那里它感染了lodgepole， jack （P. banksiana）和lodgepole × jack松混交林。它对杰克松的攻击是特别值得关注的，因为这种常见物种从北方森林延伸到加拿大东海岸。甲虫优先攻击成熟的树木，它们在树皮下觅食和繁殖。甲虫引入蓝斑真菌（Grosmannia clavigera, Leptographium longiclavatum），阻断水分和养分的运输，限制树木的防御反应，并为甲虫后代提供营养。控制措施仅限于摧毁受感染的树木。自2006年以来，艾伯塔省政府已经花费了近5亿美元来检测和消灭这种甲虫。球孢白僵菌是一种攻击甲虫并杀死它们的真菌。虽然该物种可以在各种节肢动物中定居，但有些菌株的活性谱很窄。这种真菌已经被用作对付其他昆虫的生物杀虫剂。虽然在实验室中球孢白丝酵母对黄皮棘球霉和其他树皮甲虫是致命的，但现场试验往往不能证明真菌病的繁殖或甲虫种群的控制。然而，由于球孢白僵菌在森林凋落物中的持久性，它与欧洲云杉树皮甲虫（Ips typographus）在野外试验中取得了成功。加拿大的森林影响气候，促进二氧化碳吸收，提供野生动物栖息地，清洁水和其他生态系统服务。2013年，他们占加拿大GDP的198亿美元。本申请申请资金用于检查球孢白僵菌真菌菌株的选择，产生和测试，这些菌株对环境强健，对山松甲虫特别致命，易于直接控制。该项目将对真菌进行改造：(1)增强紫外线和耐旱性，以改善田间应用；（ii）产生松甲虫性信息素，吸引昆虫靠近受感染的个体。实验室药效测试之后将进行对照田间试验，以评估真菌在自然条件下对昆虫的生物防治效果，并检查对理想昆虫（如授粉昆虫）的非特异性致死率。

The mountain pine beetle (Dendroctonus ponderosae) has killed >50% of mature lodgepole pine trees (Pinus contorta) across >16 million ha of British Columbia. It has now crossed the Rocky Mountains into Alberta, where it infests lodgepole, jack (P. banksiana) & lodgepole × jack pine hybrid forests. Its attack on jack pine is of special concern as this common species extends across the boreal forest to Canada's East Coast. Beetles preferentially attack mature trees where they feed & reproduce below the bark. Beetles introduce blue stain fungi (Grosmannia clavigera, Leptographium longiclavatum) that block water & nutrient transport, limit trees defensive responses, & provide nutrients to beetle offspring. Control efforts are limited to destruction of infested trees. Since 2006, the Alberta government has spent nearly $500 million to detect & eradicate the beetles. Beauveria bassiana is a fungus that attacks beetles & kills them. Although the species can colonize a wide variety of arthropods, some strains have narrow spectra of activity. This fungus is already in use as a biological insecticide against other insects. Although B. bassiana is lethal to D. ponderosae & other bark beetles in the lab, field tests often fail to demonstrate propagation of the mycosis or control of beetle populations. However, B. bassiana was successful in field tests with European spruce bark beetle (Ips typographus) due to its persistence in forest litter. Canada's forests influence climate, contribute to CO2 uptake, provide wildlife habitat, clean water & other ecosystem services. They accounted for $19.8 billion of Canada's GDP in 2013. This application requests funding to examine selection, generation & testing of fungal strains of B. bassiana that are environmentally robust, specifically lethal to the mountain pine beetle & readily deployed for direct control. The project will engineer into the fungus: (i) enhanced UV & drought tolerance to improve field applications; & (ii) pine beetle sex pheromone production to attract the insects to infected individuals. Lab tests of efficacy will be followed by controlled field trials to evaluate biocontrol of the insect by the fungus under natural conditions & examine nonspecific lethality to desirable (e.g. pollinating) insects.