大额牛主食竹子的瘤胃微生物代谢机制及高活性纤维素酶系研究

大额牛为中国唯一的半野生半家养的珍稀牛种资源，主食竹子等高纤维物质仍能获得良好的生长和增重，具有粗纤维消化能力强的特点；大额牛无疑是高效木质纤维降解酶筛选和发掘的珍贵种质资源。本项目在前期研究的基础上，拟采集相同生境大额牛和云南黄牛各6头瘤胃内容物，运用瘤胃微生物组学技术比较大额牛和黄牛瘤胃微生物群落组成及功能基因差异（宏基因组10X Genomics测序），瘤胃差异代谢物及代谢通路（代谢组学）以及通过组学的关联分析构建大额牛瘤胃微生物代谢通路及功能基因调控互作网络；在此基础上筛查大额牛高效降解木质纤维的功能基因，并首次构建高活性的纤维素酶系及在E.coli中实现共表达与定向改造；同时采用人工瘤胃模拟系统体外研究该纤维素酶系对纤维降解特性；预期阐明大额牛瘤胃功能微生物与功能基因的代谢分子机制和开发高活性的纤维素复合酶；为反刍动物饲料高效转化利用以及为发掘大额牛优良种质资源提供科学支撑。

The gayal is a rare semi-wild bovine species distributed throughout china. It can graze grasses including bamboo as well as reeds and other plant species, and attains higher mature live weights than that of Yunnan yellow cattle maintained in similar environments. Previous studies confirmed that ruminal microbes and cellulases of gayal had the efficient digestion of fiber. Therefore, it is no doubt that gayal is valuable species resources for screening high-efficient cellulase.This project will compare the difference of ruminal microbiota, functional genes and rumen metabolites by omics approaches from ruminal contents of 6 gayals and 6 Yunnan yellow cattles under the native environments. We will analyse rumen microbial flora and functional genes (Metagenomics, 10X Genomics sequencing, anticipative total “metagenome” size of 600 Gb), rumen differential metabolites and metabolic pathways (Metabonomics). Furthermore, the correlation of significant microbiota flora, functional genes and related metabolites will be analyzed to construct the interaction network. We will try to construct, co-express and co-modify ruminal specific cellulosome of gayal in E.coli. In the meantime, we will also use artificial rumen simulation system to evaluate cellulosome activity and stability in rumen fluid .The results will reveal metabolic mechanism which ruminal microbes can more effectively degrade fibrous feed,especially bamboo, and provide an effective way for transforming of ruminant feeds and utilization of biology energy sources, and also contribute to developing unique biodiversity resources in Yunnan Province.