滇藏热泉arxA基因型厌氧砷氧化原核微生物多样性及其影响因素

Diversity of arsenic-oxidizing prokaryotes containing arxA gene in Yunnan-Tibet hot springs and the influencing factors

摘要:

【目的】探究滇藏地区热泉沉积物微生物及arxA基因的多样性及其影响因素。【方法】采用Illumina MiSeq高通量测序技术和统计学的分析方法,针对3个滇藏地热区的22个样点,进行地球化学分析及微生物多样性分析,并分析其与环境因子之间的相关性。【结果】沉积物微生物群落主要门类及其丰度占比为Chloroflexi(21.27%)、Deinococcus-Thermus(17.25%)、Aquificae(13.39%)、Proteobacteria(9.27%)、Acetothermia(8.3%)、Bacteroidetes(4.96%)与Crenarchaeota(4.57%);具有arxA基因的微生物主要门类及其丰度占比分别为Proteobacteria(64.87%)、Bipolaricaulota(9.55%)、Deinococcus-Thermus(6.42%)与Crenarchaeota(4.05%);不同地热区优势种群有所差异,主要受温度、pH值、砷浓度、总溶解固体(TDS)及海拔等因素的影响,Mantel检验呈显著相关性(P<0.001)。【结论】沉积物中具有arxA基因的微生物主要以Proteobacteria为主;不同地热区受到不同环境因子及地理隔离因素的影响,优势群落存在一定地理分布差异;然而,其中具有arxA基因的微生物与pH值无相关性,主要受控于海拔、砷浓度、TDS与空间因素等,体现了此类微生物生理代谢特征的差异性与特殊性。

关键词:滇藏地区;热泉;砷氧化;arxA基因

Abstract:

[Objective] To study the diversity of microorganisms in sediments of hot springs in Yunnan and Tibet, the existence of arxA in them, and the influencing factors. [Methods] Illumina MiSeq and statistical analysis were employed for geochemical analysis and microbial diversity analysis of the 22 samples in 3 geothermal areas in Yunnan and Tibet and the relationship between the microorganisms and environmental factors was elucidated. [Results] The dominant phyla in the sediments were Chloroflexi (abundance: 21.27%), Deinococcus-Thermus (abundance: 17.25%), Aquificae (abundance: 13.39%), Proteobacteria (abundance: 9.27%), Acetothermia (abundance: 8.3%), Bacteroidetes (abundance: 4.96%), and Crenarchaeota (abundance: 4.57%). arxA gene-harboring phyla were Proteobacteria (abundance: 64.87%), Bipolaricaulota (abundance: 9.55%), Deinococcus-Thermus (abundance: 6.42%), and Crenarchaeota (abundance: 4.05%). The dominant populations were different among the geothermal areas, which was mainly caused by the temperature, pH, arsenic content, total dissolved solids (TDS), and altitude, as manifested by the significant correlation (P<0.001) between the microorganisms and the environmental factors verified by Mantel test. [Conclusion] arxA gene-harboring microorganisms in the sediments of hot springs were dominated by Proteobacteria and were affected by environmental factors and geographical isolation. They exhibited geographical distribution pattern, as indicated by unique dominant microbial groups in different geothermal areas. In contrast, the arxA gene-containing microbial groups showed no correlation with pH, but were mainly influenced by altitude, arsenic content, TDS, and spatial variables. This suggests the unique physiological characteristics of them among the whole microbial communities.

Key words:Yunnan and Tibet;hot springs;arsenic oxidation;arxA gene