不同风化程度凝灰岩表生细菌群落结构与功能比较

Community Structures and Functions of Epibiotic Bacteria in Tuff with Different Weathering Degrees

本研究利用高通量测序技术、Biolog EcoPlate检测法结合生物信息学分析手段比较研究了江西省抚州市东乡县低风化(LR)和高风化凝灰岩(MR)以及附近红壤(SS)样品表生细菌群落α多样性、群落结构与功能的差异。结果表明,随着凝灰岩风化程度的加剧,细菌群落独特OTU数目、Chao1指数以及微生物碳利用率和代谢多样性香农指数逐渐增高。酸杆菌门(Acidobacteria,相对丰度17.8%~40.7%)、放线菌门(Actinobacteria,9.2%~29.2%)和变形菌门(Proteobacteria,18.8%~34.6%)是该生境中的优势菌门。随着凝灰岩风化程度的加剧,Acidobacteria相对丰度越来越高,而Actinobacteria和Alphaproteobacteria相对丰度逐渐降低。岩石样品pH、有机质(OM)含量以及有效态P、K和Ca的含量解释了凝灰岩表生细菌99%的群落结构变异。PICRUSt2对细菌群落功能预测结果表明,3组样品中编码碳酸酐酶(CA)、鞭毛合成和有机酸产生功能基因相对丰度的排序为SS>MR>LR,而LR中产铁载体相关功能基因相对丰度最高。综上,随着风化程度的加剧,凝灰岩表生细菌群落α-多样性随之升高,群落结构发生显著变化,表生细菌群落可能同时通过多种方式风化凝灰岩;且微生物群落对于不同种类碳源具有不同的优先利用模式。研究结果进一步丰富了凝灰岩风化形成红壤过程中微生物群落结构与功能的变迁规律。

In this study,the less(LR)and more(MR)weathered rock samples and the adjacent red soil samples(SS)were collected from Dongxiang County,Fuzhou,Jiangxi Province to compare the differences in diversity,structure and ecological functions of bacterial communities by applying the high-throughput sequencing of partial bacterial 16S rRNA genes,a metabolic profiling technique(Biolog EcoPlate)and bioinformatics analysis.It was found that as rock weathering degree intensified,the number of unique OTUs and Chao1 index of bacterial communities,as well as microbial carbon utilization and metabolic diversity Shannon index gradually increased.Acidobacterium(with relative abundance of 17.8%-40.7%),Actinobacteria(9.2%-9.2%)and Proteobacteria(18.8%-34.6%)were the most dominant phyla in these habitats,the relative abundance of Acidobacteria increased,while the relative abundances of Actinobacteria and Alphaproteobacterium decreased.pH,the contents of organic matter(OM),available P,K and Ca of rock(or soil)samples explained 99%of the community structure variation of tuff(or soil)surface bacterial communities.The prediction results of bacterial community function by PICRUSt2 showed that the relative abundances of genes encoding carbonic anhydrase(CA),flagella synthesis and organic acid production in the three groups of samples were in the order of SS>MR>LR,with LR having the highest relative abundance of iron producing carrier related functional genes.In conclusion,as the degree of rock weathering intensifies,α-diversity of bacterial community on tuff surface increases,and the community structure changes significantly changes.Bacterial communities inhabiting rock surface might simultaneously weather tuff in multiple ways.Additionally,microbial communities inhabiting tuff surfaces with different weathering degrees had different priority utilization patterns for different carbon sources.The present study further enriched the changes in microbial community structure and function during the weathering process from tuff to red soil.