黄海陆架区硝化螺菌门趋磁细菌的特性及进化起源研究

Magnetotactic bacteria (MTB) consist of gram negative bacteria with diverse morphologies, they can swim along the magnetic field, which can orient and navigate along geomagnetic field lines. MTB can form intracellular membrane-bounded, nano-sized, and single-domain crystals under genetically control of Mangnetosome Island, called magnetosomes, which have specific morphologies and arrangements. MTB are considered to be the best model organisms in the study of biomagnetism and biomineralization. Magnetotactic bacteria belonging to Nitrospira were only found in freshwater environment. Recently, we detected magnetotactic bacteria within phylum Nitrospira in the sediments of Yellow Sea. However, the taxonomic position characterization and evolutionary origin are unknown. This project will investigate these marine magnetotactic bacteria in the shelf area of Yellow Sea. During the long-term investigation and analysis, we will analyze the variation of marine magnetotactic bacterial species composition, and obtain new marine magnetotactic bacterial species and 16S rDNA information, and then enrich marine microbial resource library. We will analysis the distribution of marine magnetotactic bacteria in the sediments in the Yellow Sea, and analysis the relationship between the distribution and environmental factors, to find the key factor affecting the variation of marine magnetotactic bacterial abundance. We will study characterization of magnetotactic bacteria within Nitrospirae, including shape, magnetosome and so on. We will obtain pure cells of marine magnetotactic bacteria within Nitrospirae using micromanipulation, and study their taxonomic and phylogenetic position. Then we will obtain their genome sequence by whole genome amplification, and analyse genes involved in magnetosome formation and iron metabolism, and study the evolutionary origin of marine magnetotactic bacteria with freshwater magnetotactic bacteria within Nitrospirae by comparative analysis with all known magnetosome island. This project will help us to know ecology roles and evolutionary origin of magnetotactic bacteria, and supply new model organisms for biomagnetism and biomineralization research.

趋磁细菌是一类沿着磁力线运动的特殊细菌，在基因调控下能合成磁小体，并借助其定位作用在磁场下进行趋磁-趋氧运动，被认为是生物磁学和生物矿化研究最好的模式生物。其中，硝化螺菌门趋磁细菌仅在湖泊等淡水环境发现，前期我们对黄海陆架区沉积物中发现了硝化螺菌门趋磁细菌。本项目将通过研究黄海陆架区硝化螺菌门趋磁细菌的种类组成和分布，获取趋磁细菌种质资源信息，丰富我国微生物资源库；对黄海陆架区硝化螺菌门趋磁细菌进行系统分类地位鉴定和特性研究，并分析与淡水硝化螺菌门的异同；通过单细胞基因组测序技术获得黄海陆架区硝化螺菌门趋磁细菌的基因组，对铁代谢、磁小体岛、鞭毛、光感应蛋白以及趋化蛋白等相关基因进行分析，探讨陆架海与淡水硝化螺菌门趋磁细菌的进化关系，认识海洋硝化螺菌门趋磁细菌的系统分类、进化地位和起源。本项目将为深入认识海洋趋磁细菌生态作用和进化起源打下基础，也为生物磁学和生物矿化研究提供新的模式生物。

趋磁细菌是一类沿着磁力线运动的特殊细菌，在基因调控下能合成磁小体，并借助其定位作用在磁场下进行趋磁-趋氧运动，被认为是生物磁学和生物矿化研究最好的模式生物。其中的硝化螺菌门趋磁细菌仅在湖泊等淡水环境发现。本项目，我们针对黄海陆架区沉积物中发现的硝化螺菌门趋磁细菌，研究其种类组成和分布规律，认识趋磁细菌的多样性和群落结构，获取趋磁细菌种质资源信息，丰富我国微生物资源库；对黄海陆架区硝化螺菌门趋磁细菌进行系统分类地位鉴定，并进行形态、运动、磁小体等生物矿化特性研究，并分析与淡水硝化螺菌门的异同，较全面地认识海洋硝化螺菌门趋磁细菌的特征；通过单细胞基因组测序技术获得4种海洋硝化螺菌门趋磁细菌的基因组，对其进行注释和代谢通路重构，重点分析铁代谢、磁小体岛、鞭毛、光感应蛋白以及趋化蛋白等相关基因，探讨海洋硝化螺菌门趋磁细菌的生态作用，同时通过海洋与淡水硝化螺菌门趋磁细菌的基因组的比较，分析基因组的进化过程及磁小体岛的来源，认识海洋硝化螺菌门趋磁细菌的系统分类、进化地位和起源。本项目将为深入认识海洋趋磁细菌生态作用和进化起源打下基础，也为生物磁学和生物矿化研究提供新的模式生物。