砷氧化菌株的筛选及Bosea sp.AS-1基因组分析

Screening and genome analysis of arsenite-oxidizing strain Bosea sp. AS-1

摘要:

[目的] 对湖南省锡矿山地区的砷氧化菌株的种属进行初步鉴定，并对砷锑氧化菌株Bosea sp.AS-1（简称AS-1）进行全基因组测序和生物信息学分析。[方法] 分离砷氧化菌株，并利用16S rRNA基因测序进行菌种鉴定。在此基础上，对能够高效氧化砷的菌株AS-1进行全基因组测序，对测序数据进行基因组装和功能注释、COG、GO及KEGG聚类分析，以及次级代谢产物合成基因簇与代谢途径预测等。[结果] 湖南省锡矿山的砷氧化菌株主要分布在α-、β-、γ-变形菌纲以及厚壁菌门。菌株AS-1基因组的测序结果显示AS-1基因组包含一条大小为5.536 Mb环状染色体和两个大小分别为189.9 kb和112.1 kb的质粒。对AS-1基因组进一步分析发现该菌株的基因组中包含砷锑代谢相关基因，还有鞭毛形成、鞭毛运动及生物膜形成的基因，这些基因的存在可能与AS-1能高效耐受和氧化砷和锑的特性相关。此外，菌株AS-1中还存在部分碳固定基因和硫氧化基因，这暗示着AS-1能够进行自养生长并氧化环境中的硫元素。[结论] 菌株AS-1可以在自养条件下生长并且能够氧化Sb（III）为Sb（V）。

Abstract:

[Objective] In this study, we aimed to characterize the community structure of arsenite-oxidizing bacteria in Xikuangshan of Hunan Province, and the whole genome of an arsenite-antimonite-oxidizing strain Bosea sp. AS-1 (Abbreviation:AS-1). [Methods] Arsenite-oxidizing bacterial strains were isolated from the samples collected in Xikuangshan, and 16S rRNA genes were sequenced for phylogenic analysis. Whole genome of strain AS-1 was sequenced and analyzed using relevant software and databases for genome assembly, gene prediction and functional annotation. [Results] The arsenite-oxidizing bacteria in Xikuangshan were mainly distributed in α-, β-, γ-Proteobacteria and Firmicutes. AS-1's genome contained one circular chromosome with a size of 5.536 Mb and two plasmids of 189.9 kb and 112.1 kb, respectively. Further analysis on AS-1's genomic data reveal many genes related to arsenic and antimony metabolism, as well as flagella formation, flagellar movement, and biofilm formation. These genes may be involved in AS-1's resistance to high level of arsenic and antimony in environment. Besides, several carbon-fixation genes and sulfur-oxidizing genes were also found in the genome of AS-1, suggesting that AS-1 may grow autotrophically and oxidize sulfur. [Conclusion] Subsequent experiments confirmed autotrophic growth of AS-1.