新型辅助类群噬几丁质属（Chitinophaga）细菌对粘细菌诱导特性及诱导机制研究

Myxobacteria are famous for their complicated multicellular behavior and excellent production ability of secondary metabolites, and are thus among important microbial resources for drug screening. Technique for isolation of myxobacteria based on helper bacteria (HB) is one of the main part of isolation. However effective HB are very limited and the mechanism of induction is also unclear, this restricted the improvement of myxobacteria isolation system and acquisition of new resources. In the early stage, the applicant obtained 4 Chitinophaga strains and found that some of them were good HBs of myxobacteria. This project is based on the novel HB and valid published species to evaluate the incubation specificity of myxobacteria genus. Based on the novel HB to evaluate the isolation effectiveness of unknown myxobacteria in different soils. Through genomic and comparative genomics analysis of HB to explore the response factor related to exopolysaccharide (EPS) and gliding of the HB in the process of myxobacteria predation. This study will provide a basis for the formation of targeted isolation systems of different genera, and provide new ideas and theoretical knowledge for solving the problem of difficult to purify.

粘细菌具有复杂的多细胞群体行为，能够产生丰富的次级代谢产物，是一类重要的药源微生物。辅助菌诱导是粘细菌主要分离方法之一，但当前有效的辅助类群极为有限，对于辅助菌的诱导机制也并不清晰，严重制约了粘细菌分离体系改进和新资源的获得。申请人前期获得了4株噬几丁质属（Chitinophaga）菌株，并初步验证该属含有粘细菌的有效辅助菌。本项目基于此新的辅助类群，以粘细菌已知种属为待测对象，系统评价新型辅助菌对粘细菌的诱导种属特异性；基于新型辅助菌进行环境未知粘细菌类群进行分离效果评价；通过对辅助菌进行基因组学、比较基因组学分析，探究辅助菌对粘细菌捕食过程的胞外多糖、运动性相关的响应因子。本研究结果将为形成不同种属的靶向分离体系建立基础，为解决粘细菌难以纯化的问题提供新的思路和理论依据。

粘细菌是一类能产生丰富次级代谢产物和水解酶类的难培养药源微生物，辅助菌诱导是粘细菌主要分离方法之一。本项目基于前期获得的4株Chitinophaga属细菌，并发现该属含有粘细菌的有效辅助类群展开研究。首先，对粘细菌与Chitinophaga属互作关系评价，获得一株粘细菌有效辅助菌Chitinophaga sp. K2CV101002-2及一株广谱抗菌菌株Chitinophaga flava K3CV102501，比较基因组学及抑菌实验显示非辅助类群中含有次级代谢产物抑制粘细菌生长；（2）基于不同辅助菌从森林土壤中分离粘细菌33株，包含5株新物种，完成多相分类研究及稿件撰写，将其命名为Myxococcus dinghuensis sp. nov. (K15C18031901T=GDMCC 1.2319T), Myxococcus varians sp. nov. (K38C18041901T=GDMCC 1.2320T), Myxococcus qinghaiensis sp. nov. (QH3KD-4-1T=GDMCC 1.2316T), Pyxidicoccus silviterrae sp. nov. (QH1ED-7-1T=GDMCC 1.2315T) 和 Corallococcus guangdongense sp. nov. (Z5C101001T=GDMCC 1.1321T=KCTC 62366T）；进一步泛基因组分析其遗传多样性，并发现附属基因中含有大量的酶类和次级代谢产物，可能影响粘细菌捕食速率；（3）在分离粘细菌时，获得其他新属新种5株，已发表3株，将其命名为Deminuibacter soli，Ramlibacter humi，Rhizobium glycinendophyticum，另完整鉴定及撰稿菌株1株Parachryseolinea soli。本项目为粘细菌及活性化合物资源挖掘提供丰富物质基础和理论基础。