不同价态锑对蚓触圈细菌群落多样性和结构的影响

Effects of different valent antimony on the bacterial diversity and community structure of drilosphere

为研究锑(Antimony,Sb)污染土壤经蚯蚓扰动及消化前后蚓触圈(肠道、蚓穴)的细菌群落多样性和结构差异,本试验将蚯蚓暴露在Sb(Ⅲ)和Sb(Ⅴ)单一和复合处理中,结果发现:蚯蚓肠道、穴壁土、对照土3种基质的微生物多样性存在显著差异,随着培养时间和锑含量的增加,蚓触圈基质的Chao1指数、Shannon指数、Pielou指数显著降低;蚓触圈呈现出独特的微生物群落结构,在高含量复合处理的穴壁土中,Comamonas_testosteroni、Sphingobacterium_faecium、Sphingobacterium_multivorum的相对丰度高于其他菌种,结合相关性分析,表明以上3个菌种在介导Sb(Ⅲ)的转化中可能发挥着积极作用;冗余分析表明,穴壁土的丰富菌门Bacteroidetes与土壤中的Sb(Ⅲ)含量呈正相关关系,Proteobacteria与土壤中Sb(Ⅲ)含量、Sb(Ⅴ)含量、群落覆盖度呈正相关关系。研究表明,蚓触圈是一个微生物介导下锑形态转化的潜在热区。

Earthworms were exposed to soils contaminated with Sb(Ⅲ)and(or)Sb(Ⅴ)to study the differences in microbial community structure of drilosphere(gut and burrow lining)before and after the disturbance and digestion of Sb-contaminated soil by earthworms.The result shows that:the microbial diversity of earthworm gut,burrow lining,and control soil is significantly different.With the increase in culture time and Sb concentration,the Chao1 index,Shannon index,and Pielou index of the drilosphere matrix significantly reduced.The drilosphere presents a unique microbial community structure,and the relative abundances of Comamonas_testosteroni,Sphingobacterium_faecium,and Sphingobacterium_multivorum are higher than that of other species in high-concentration compositetreated burrow lining soil.Combined with the correlation analysis,this shows that the above three species may play a positive role in the mediating transformation of Sb(Ⅲ).According to redundancy analysis,there is a positive correlation between Bacteroidetes and Sb(Ⅲ)content in soil;Proteobacteria is positively correlated with the content of Sb(Ⅲ),Sb(Ⅴ),and community coverage,indicating their resistance to Sb.Thus,the drilosphere is a potential thermal zone for the microbial-mediated transformation of Sb morphology.