地衣芽孢杆菌γ-聚谷氨酸、杆菌肽代谢调控机理的系统生物学研究

Bacillus licheniformis is one of the most important bacterium in the biotechnology industry to manufactrue enzymes, antibiotics, biochemicals and consumer products. In the current project, we analyze three B. licheniformis strains with clear genetic backgrounds, similar genomic sequences and sighnificantly different metabolic products. Of these three B. licheniformis strains, ATCC 14580 strain is the model strain,which can not produce poly-γ-glutamic acid (γ-PGA) and bacitracin. WX-02 strain can high-yield γ-PGA in salt stress, and RF20-22 strain is the bacitracin-manufacture strain in biotechnology industry. Firstly, we will sequencing the transcriptomes of the above three strains in different growth time, different cultivation and stress conditions,and differently expressed genes will be analyzed. Then the metabolic network,protein-protein interaction network and regulation network of γ-PGA and bacitracin related genes in B. licheniformis will be established, and potential regulatory factors and regulation mechanisms of γ-PGA or bacitracin biosynthesis will be investigated. Finally, we will build 3~5 genetically recombinant strains for strengthening the regulatory factors or missing /covering the major regulatory genes, to verify whether the poteitial regulatory factors can promote the high-yielding of γ-PGA or bacitracin. The implementation of the project will investigate the regulation network of γ-PGA and bacitracin synthesis in B. licheniformis, and provide a solid foundation for building highly efficient genetically recombinant B. licheniformis strains for large-scale γ-PGA and bacitracin production.

本项目以生物制造产业中的重要生产菌株地衣芽胞杆菌（Bacillus licheniformis）为研究材料，首先测定三株遗传背景清晰、基因组序列相似、但代谢物产物明显不同的B. licheniformis菌株在不同生长时间、不同培养和胁迫条件下的转录组数据，找出它们的差异表达基因，在此基础上构建地衣芽孢杆菌的代谢网络、蛋白互作网络和基因调控网络，采用系统生物学方法对三个菌株的基因组、转录组、代谢及调控网络进行比较，寻找调控γ-聚谷氨酸和杆菌肽合成的潜在调控因子，阐明γ-聚谷氨酸（γ-PGA）和杆菌肽的代谢调控机理，最后构建3~5个重要调控因子的强化或缺失回补重组菌株，验证找到的调控因子对促进γ-PGA或杆菌肽高效合成的调控作用。本研究的顺利实施可以系统深入地研究地衣芽孢杆菌中γ-PGA和杆菌肽的代谢调控机理，为构建γ-PGA和杆菌肽高效规模化生产的基因工程菌株奠定理论基础。

本项目以生物制造产业中的重要生产菌株地衣芽胞杆菌（Bacillus licheniformis）为研究材料，测定三株遗传背景清晰、基因组序列相似、但代谢物产物明显不同的B. licheniformis菌株在不同生长时间、不同培养和胁迫条件下的转录组数据，鉴定了差异表达基因、反义RNA及非编码区的小RNA，识别了操纵子结构，在此基础上构建了地衣芽孢杆菌的代谢网络、蛋白互作网络和基因调控网络，采用系统生物学方法对三个菌株的基因组、转录组、代谢及调控网络进行比较，寻找调控γ-聚谷氨酸和杆菌肽合成的潜在调控因子，阐明γ-聚谷氨酸（γ-PGA）和杆菌肽的代谢调控机理，进一步对degU、motA、yhbJ和swrA等重要调控因子进行了缺失菌株构建及基因回补，发现degU对菌体合成γ-聚谷氨酸起至关重要的作用。本研究的顺利实施系统深入地研究地衣芽孢杆菌中γ-PGA和杆菌肽的代谢调控机理，为构建γ-PGA和杆菌肽高效规模化生产的基因工程菌株奠定了坚实基础。