锡林河流域潜在异养硝化-好氧反硝化菌群的陆向分异及影响因素

Landward differentiation and influencing factors of heterotrophic nitrification-aerobic denitrification bacterial populations in Xilin River Basin

为阐明异养硝化-好氧反硝化(HN-AD)菌群的空间分化及其环境影响因素,本研究沿着水生-湿生-旱生的陆向梯度采集沉积物/土壤样品进行细菌16S rRNA基因高通量测序、环境因子检测及生物信息学分析.结果显示,副球菌属主要分布于水生环境,陶厄氏菌属、不动杆菌属、气单胞菌属、假单胞菌属主要分布于湿生环境,芽孢杆菌属、节杆菌属和鞘氨醇单胞菌属主要分布于旱生环境;沿着陆向梯度,Shannon-Weiner和Pielou指数均呈先升后降趋势,Simpson指数呈上升趋势.黏粒、粉粒、硝态氮含量对潜在HN-AD菌群组成陆向分异的总解释度分别为79.51%、8.15%、7.81%,砂粒、粉粒、含水量对潜在HN-AD菌群多样性陆向分异的总解释度分别为89.79%、4.34%、2.75%,这些环境因子均发挥直接作用.HN-AD菌群组成及多样性指数存在明显的陆向分布特征并与粉黏粒等环境因子密切相关.研究结果可为废水处理和土壤修复领域寻找新型HN-AD微生物资源提供科学依据.

This study aimed to clarify the spatial differentiation of heterotrophic nitrification-aerobic denitrification(HN-AD)bacterial populations and their influencing factors.Along a landward gradient,21 sediment/soil samples were collected from aquatic riverbed,the hygric floodplain to xeric terrace zones.The composition and diversity of HN-AD bacterial populations at genus level were analyzed by 16S rRNA gene high-throughput sequencing.The relationship between potential HN-AD bacterial populations and environmental factors was studied based on redundancy analysis(RDA),multivariate regression tree(MRT)and structural equation modeling(SEM).The results showed that Paracoccus was mainly distributed in the aquatic environment.While Thauera,Acinetobacter,Aeromonas and Pseudomonas were mainly distributed in hygric environment,and Bacillus,Arthrobacter and Sphingomonas were mainly distributed in xeric environment.Along the landward gradient,the Shannon Weiner and Pielou indexes first increased and then decreased,while Simpson index increased gradually.MRT analysis showed that the content of clay particles,silt particles and nitrate accounted for 79.51%,8.15%and 7.81%of the landward differentiation of potential HN-AD bacterial compositions,respectively.Meanwhile,the content of sand particles,silt particles and moisture accounted for 89.79%,4.34%and 2.75%of the landward differentiation of potential HN-AD bacterialα-diversity,respectively.The results of SEM showed that the content of clay particles,silt particles,nitrate nitrogen and moisture had positively direct effects on the landward differentiation of HN-AD bacterial populations.The HN-AD bacterial populations had obvious landward distribution characteristics,closely related to sediment/soil physicochemical factors such as clay and silt particles.The results can provide scientific basis for searching novel HN-AD bacteria for wastewater treatment and soil remediation.