Zhou Fangyuan, Lou Qiaozhe, Wang Bo, Xu Letian, Cheng Chihang, Lu Min, Sun Jianghua
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci Rep. 2016 Feb 3;6:20135. doi: 10.1038/srep20135.
Insect-microbe interaction is a key area of research in multiplayer symbiosis, yet little is known about the role of microbe-microbe interactions in insect-microbe symbioses. The red turpentine beetle (RTB) has destroyed millions of healthy pines in China and forms context-dependent relationships with associated fungi. The adult-associated fungus Leptographium procerum have played key roles in RTB colonization. However, common fungal associates (L. procerum and Ophiostoma minus) with RTB larvae compete for carbohydrates. Here, we report that dominant bacteria associated with RTB larvae buffer the competition by inhibiting the growth and D-glucose consumption of O. minus. However, they didn't inhibit the growth of L. procerum and forced this fungus to consume D-pinitol before consuming D-glucose, even though D-glucose was available and a better carbon source not only for L. procerum but also for RTB larvae and associated bacteria. This suggests the most frequently isolated bacteria associated with RTB larvae could affect fungal growth and the sequence of carbohydrate consumption. Thus, this regulates carbohydrate allocation in the RTB larva-microbe community, which may in turn benefit RTB larvae development. We also discuss the mechanism of carbohydrate allocation in the RTB larva-microbe community, and its potential contribution to the maintenance of a symbiotic community.
昆虫与微生物的相互作用是多重共生研究的一个关键领域，但对于微生物间相互作用在昆虫与微生物共生关系中的作用却知之甚少。微红梢斑螟在中国已毁掉了数百万棵健康的松树，并与相关真菌形成了依赖环境的关系。与成虫相关的真菌长喙壳菌在微红梢斑螟的定殖过程中发挥了关键作用。然而，与微红梢斑螟幼虫相关的常见真菌（长喙壳菌和短喙壳菌）会竞争碳水化合物。在此，我们报告称，与微红梢斑螟幼虫相关的优势细菌通过抑制短喙壳菌的生长和D-葡萄糖消耗来缓冲这种竞争。然而，它们并不抑制长喙壳菌的生长，并且迫使这种真菌在消耗D-葡萄糖之前先消耗D-松醇，尽管D-葡萄糖是可利用的，而且不仅对长喙壳菌，对微红梢斑螟幼虫及相关细菌而言都是更好的碳源。这表明，与微红梢斑螟幼虫最常分离出的细菌可能会影响真菌生长以及碳水化合物消耗顺序。因此，这调节了微红梢斑螟幼虫-微生物群落中的碳水化合物分配，这反过来可能有利于微红梢斑螟幼虫的发育。我们还讨论了微红梢斑螟幼虫-微生物群落中碳水化合物分配的机制及其对维持共生群落的潜在贡献。
