褐飞虱 -内生共生真菌YLS -内生共生细菌的共生营养代谢网分析

The brown planthopper (BPH, Nilaparvata lugens) is the most destructive rice pest. BPH harbors a large amount of intracellular yeast-like symbiotes (YLS) and symbiont bacteria in the fat body cells. BPH surviving on the rice phloem sap as sole food source, its quick adaptation to new resistant rice varieties and its high productivity are believed to be closely related to the endosymbionts.However, as the unavailability of the genome sequences of BPH and its endosymbionts up to date, the YLS phylogenetic position is not clear yet, the trophic complementarity between BPH and YLS was limited on individual gene level and the endosymbiont bacteria was not considered together. Recently, we completed the sequencing and assembly of the 3 genomes for BPH, YLS and the main endosymbiont bacterium Arsenophonus, respectively. Based on the sequences of the 3 genomes, a metabolic complementarity network of amino acid, sterol and vitamins among the 3 species will be set up in this project, and the expression and regulation of genes in the network will be further analyzed. The result will reveal the global trophic interaction relationship and their regulations among BPH- - YLS- - Arsenophonus on the genome and transcriptome level, which may be serve as a modle for the further studies on trophic interaction of"insect- - fungus- - (endosymbiont bacterium)"in the life science. The result also will provide a basis for the further studies on the BPH disaster mechanism and its control from the point view of symbiosis.

褐飞虱是水稻最主要害虫，脂肪体内存在共生真菌YLS和共生细菌。褐飞虱能专一性吸食水稻汁液生存、对水稻抗性品种有快速的适应性、具高繁殖能力都可能与其体内共生菌密切相关。但目前由于缺乏宿主和共生菌基因组信息,褐飞虱共生真菌YLS分类地位还不清楚，对褐飞虱和YLS的最基本的共生关系即互相之间的营养关系研究还都仅限于个别基因、并且都没有综合考虑共生细菌的联合作用。最近我们分别完成了褐飞虱、YLS、主要共生细菌全基因组序列测定和组装，本项目拟在此基础上，建立褐飞虱-共生真菌-共生细菌的氨基酸、固醇类、维生素等营养代谢互补关系网络，并进一步分析网络中各基因的表达与调控，在全基因组和基因表达调控水平上全面揭示褐飞虱-体内共生真菌-体内共生细菌的营养互作关系。结果将为生命科学建立一种"昆虫-内共生真菌（-内共生细菌）共生营养互作网络"研究参考模式，同时为从共生系统角度阐明褐飞虱成灾机理和防治研究提供基础

褐飞虱是水稻最主要害虫，也是典型的单植食性昆虫，只取食水稻汁液，能长距离迁飞。该虫在亚洲大约每隔三年爆发一次。褐飞虱脂肪体细胞内存在大量的共生真菌YLS和共生细菌。为了更好地理解单吸一种水稻植物汁液的褐飞虱何以能很好生存和快速繁殖和为害虫防治提供参考，我们分析了褐飞虱和它的两种内共生菌的基因组。根据3个基因组序列信息，我们构建了飞虱-共生真菌-共生细菌三个物种的的氨基酸、固醇类、维生素等营养代谢互补关系网络。我们描述了1.14的褐飞虱基因组，以及帮助其专一利用水稻营养的2个共生菌基因组。这些互补基因组功能与褐飞虱的水稻取食专一性是高度契合的。对褐飞虱取食营养极不平衡的水稻汁液必不可少的生化通路基因，不少在褐飞虱基因组中是缺缺乏的，但这些保守的生化通路基因都存在于共生菌基因组中并扩张，其进化出了与宿主互补的共生营养需求相适应的基因集。我们的结果揭示了褐飞虱通过一系列复杂的生物过程的适应，变成能高度危害专一寄主水稻的大害虫。这些结果也为抑菌治虫提供了新思路。