共生真菌对Euops属卷叶象甲幼虫发育的营养功能及分子机制研究

在长期的进化历程中，很多昆虫进化出了培植真菌作为食物的行为。目前研究较为详尽的是白蚁、食菌甲虫和attine蚂蚁等社会性昆虫与真菌共生体系，而非社会性植菌昆虫的研究实例则较少。Euops属卷叶象甲作为一类典型的非社会性植菌昆虫，我们前期研究发现，卷叶象甲Euops chinensis幼虫以叶苞组织和培植真菌Penicillium herquei的菌丝为食，但共生真菌在幼虫食物中的贡献及营养功能尚未明确。本项目拟通过稳定同位素分析，确定共生真菌在不同发育阶段卷叶象甲幼虫食物中的贡献比例；通过一系列生化分析，分别验证共生菌为不同发育阶段幼虫提供N素、甾醇、氨基酸等的营养潜能；最后通过共生真菌基因组测序分析，从基因水平阐明共生真菌在营养供给及物质合成方面的分子机制。研究结果将能深入揭示共生真菌在非社会性植菌昆虫营养生态学中的作用机制，丰富昆虫-微生物共生及协同进化理论体系。

During the long-term evolutionary process, some insects have developed a habit of cultivating fungi for food. Fungus cultivation in nonsocial insects are relatively few documented as compared to those social insects such as termites, ambrosia beetles and attine ants. Leaf-rolling weevils of the genus Euops represents a kind of typical fungal cultivation in non-social insects, our previous studies found that the larva of Euops chinensis feeds on the mixtures of cradle tissues and the mycelia of Penicillium herquei, but specific nutritional roles of the fungus in the food of the Euops weevils’ larva are still not clear. The aims of current proposal are: 1) to determine the relative contribution of P. herquei to the food of the Euops weevil’s larva at different developmental stages by stable isotope analysis; 2) to identify whether P. herquei can provide the larva at different developmental stages with N, amino acids and/or sterols, respectively, by a series of biochemical analysis; 3) to elucidate the molecular mechanisms of the fungus involving in nutrition provision and material synthesis at gene level by genome sequence and analysis of P. herquei. The outcomes will not only comprehensively reveal microbial dimensions in nutritional ecology of those nonsocial fungus-cultivating insects, but also improve our knowledge of symbiosis and coevolution between insects and microbes.