Heterotrophy-coordinated diazotrophy is associated with significant changes of rare taxa in soil microbiome  

作　　者：Wei GAO Lianfeng WANG Zhongjun JIA 

机构地区：[1]State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008(China) [2]University of Chinese Academy of Sciences,Beijing 100049(China) [3]College of Environmental and Chemical Engineering,Dalian Jiaotong University,Dalian 116028(China)

出　　处：《Pedosphere》2022年第3期402-413,共12页土壤圈（英文版）

基　　金：financially supported by the National Science Foundation of China(Nos.91751204,41530857,and 41471205);the National Basic Research Program of China(No.2015CB150501);the Strategic Priority Research Program of Chinese Academy of Sciences(CAS)(No.XDB15040000)。

摘　　要：Soil heterotrophic respiration during decomposition of carbon(C)-rich organic matter plays a vital role in sustaining soil fertility.However,it remains poorly understood whether dinitrogen(N_(2))fixation occurs in support of soil heterotrophic respiration.In this study,^(15)N_(2)-tracing indicated that strong N_(2)fixation occurred during heterotrophic respiration of carbon-rich glucose.Soil organic ^(15)N increased from 0.37 atom%to 2.50 atom%under aerobic conditions and to 4.23 atom%under anaerobic conditions,while the concomitant CO_(2)flux increased by 12.0-fold under aerobic conditions and 5.18-fold under anaerobic conditions.Soil N_(2)fixation was completely absent in soils replete with inorganic N,although soil N bioavailability did not alter soil respiration.High-throughput sequencing of the 16S rRNA gene further indicated that:i)under aerobic conditions,only 15.2%of soil microbiome responded positively to glucose addition,and these responses were significantly associated with soil respiration and N_(2)fixation and ii)under anaerobic conditions,the percentage of responses was even lower at 5.70%.Intriguingly,more than 95%of these responses were originally rare with<0.5%relative abundance in background soils,including typical N_(2)-fixing heterotrophs such as Azotobacter and Clostridium and well-recognized non-N_(2)-fixing heterotrophs such as Sporosarcina,Agromyces,and Sedimentibacter.These results suggest that only a small portion of the soil microbiome could respond quickly to the amendment of readily accessible organic C in a fluvo-aquic soil and highlighted that rare phylotypes might have played more important roles than previously appreciated in catalyzing soil C and nitrogen turnovers.Our study indicates that N_(2)fixation could be closely associated with microbial turnover of soil organic C when available in excess.

关 键 词：rare phylotypes DIAZOTROPHS heterotrophic respiration N_(2)fixation ^(15)N_(2)-tracing 

分 类 号：S154.3[农业科学—土壤学]