The anaerobic ammonium oxidizing(anammox) process has been found to play an important role in terrestrial ecosystems in recent years. However,the diversity and abundance of anammox bacteria in nitrogen(N)-rich agricul...The anaerobic ammonium oxidizing(anammox) process has been found to play an important role in terrestrial ecosystems in recent years. However,the diversity and abundance of anammox bacteria in nitrogen(N)-rich agricultural soils under high fertilizer greenhouse conditions are still unclear. Two greenhouse fields with different N fertilizer input levels were chosen, and their soil profiles were studied with molecular technologies, including quantitative polymerase chain reaction assay, a clone library, and phylogenetic analysis based on hzsB(encoding anammox hydrazine synthase β-subunit) gene. Molecular analyses suggested that anammox bacteria were at their highest density at 10–20 cm soil depth, and that the anammox bacterial abundance was significantly lower at high N than at low N. Candidatus Brocadia was the sole anammox bacterial genus throughout the soil depth profiles. The highest diversity of anammox bacteria was found at 30–40 cm soil depth, and different phylotypic clusters of Candidatus Brocadia were associated with specific soil environmental factors, such as nitrates, soil depth, and total N. Correlation analyses and redundancy analyses confirmed that high nitrate content associated with high N fertilizer input had a significant negative influence on the abundance and biodiversity of anammox bacteria. These results imply that excessive use of N fertilizer would affect arid land soil N loss to the atmosphere by the anammox pathway.展开更多
Responses of soil DIRB to lignocellulosic fractions during a 6-week microcosm incubation were investigated.Anaeromyxobacter,Bacillus,and Clostridium maintained their domi-nance throughout the incubation.Distinct DIRB ...Responses of soil DIRB to lignocellulosic fractions during a 6-week microcosm incubation were investigated.Anaeromyxobacter,Bacillus,and Clostridium maintained their domi-nance throughout the incubation.Distinct DIRB groups proliferated under specific lignocellulosic fraction amendments.Limits of insufficient ferric iron on the proliferation varied by DIRB group.Dissimilatory iron reducing bacteria(DIRB)are phylogenetically and physi-ologically diverse in paddy soils,where iron reduction closely couples with the oxidation of rice straw-derived carbon in the straw returning scenarios.However,few studies have addressed the niche differentiation within DIRB groups during the degradation of lignocellulosic fractions of rice straw.This study conducted a 6-week microcosm incubation experiment to reveal the distinct responses of DIRB groups under specific lignocellulosic fraction amendments with and without ferrihydrite(Fh)addition in a flooded paddy Ultisol.Results showed that the total absolute abundance of the 19 detected DIRB groups did not vary significantly during the incubation.Anaeromyxobacter,Bacillus,and Clostridium were the dominant DIRB groups for all lignocellulosic treatments whereas Thermincola was dominant but only under xylan amendment with Fh addition.DIRB-nodes in the co-occurrence networks of bacterial community mainly belonged to Anaeromyxobacter and Bacillus.Clostridium and Thermincola,Alkaliphilus and Anaeromyxobacter,and Alicyclobacillus,Desulfobulbus,and Desulfosporosinus were specifically proliferated under xylan,cellulose,and lignin amendments,respectively.Whether the proliferation was limited by insufficient ferric iron varied by bacterial group.These findings suggested the lignocellulosic fraction-induced niche differentiation within DIRB groups,which advanced our understanding of the ecology of DIRB in paddy soils under straw returning.展开更多
基金This study was funded by the National Natural Science Foundation of China(Nos.41401293 and 41771286),the National Science and Technology Pillar Program of China(No.2013BAD11B01),and the National Key Research and Development Program of China(No.2016YFD0200302).The authors thank Professor Peter Bottomley from Oregon State University,USA for language editing of the manuscript.
文摘The anaerobic ammonium oxidizing(anammox) process has been found to play an important role in terrestrial ecosystems in recent years. However,the diversity and abundance of anammox bacteria in nitrogen(N)-rich agricultural soils under high fertilizer greenhouse conditions are still unclear. Two greenhouse fields with different N fertilizer input levels were chosen, and their soil profiles were studied with molecular technologies, including quantitative polymerase chain reaction assay, a clone library, and phylogenetic analysis based on hzsB(encoding anammox hydrazine synthase β-subunit) gene. Molecular analyses suggested that anammox bacteria were at their highest density at 10–20 cm soil depth, and that the anammox bacterial abundance was significantly lower at high N than at low N. Candidatus Brocadia was the sole anammox bacterial genus throughout the soil depth profiles. The highest diversity of anammox bacteria was found at 30–40 cm soil depth, and different phylotypic clusters of Candidatus Brocadia were associated with specific soil environmental factors, such as nitrates, soil depth, and total N. Correlation analyses and redundancy analyses confirmed that high nitrate content associated with high N fertilizer input had a significant negative influence on the abundance and biodiversity of anammox bacteria. These results imply that excessive use of N fertilizer would affect arid land soil N loss to the atmosphere by the anammox pathway.
基金funded by the National Natural Science Foundation of China(Grant Nos.41730753 and 42177033)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(Grant No.21KJB210010)the Natural ScienceFoundationof Jiangxi Province(Grant No.20224BAB203033).
文摘Responses of soil DIRB to lignocellulosic fractions during a 6-week microcosm incubation were investigated.Anaeromyxobacter,Bacillus,and Clostridium maintained their domi-nance throughout the incubation.Distinct DIRB groups proliferated under specific lignocellulosic fraction amendments.Limits of insufficient ferric iron on the proliferation varied by DIRB group.Dissimilatory iron reducing bacteria(DIRB)are phylogenetically and physi-ologically diverse in paddy soils,where iron reduction closely couples with the oxidation of rice straw-derived carbon in the straw returning scenarios.However,few studies have addressed the niche differentiation within DIRB groups during the degradation of lignocellulosic fractions of rice straw.This study conducted a 6-week microcosm incubation experiment to reveal the distinct responses of DIRB groups under specific lignocellulosic fraction amendments with and without ferrihydrite(Fh)addition in a flooded paddy Ultisol.Results showed that the total absolute abundance of the 19 detected DIRB groups did not vary significantly during the incubation.Anaeromyxobacter,Bacillus,and Clostridium were the dominant DIRB groups for all lignocellulosic treatments whereas Thermincola was dominant but only under xylan amendment with Fh addition.DIRB-nodes in the co-occurrence networks of bacterial community mainly belonged to Anaeromyxobacter and Bacillus.Clostridium and Thermincola,Alkaliphilus and Anaeromyxobacter,and Alicyclobacillus,Desulfobulbus,and Desulfosporosinus were specifically proliferated under xylan,cellulose,and lignin amendments,respectively.Whether the proliferation was limited by insufficient ferric iron varied by bacterial group.These findings suggested the lignocellulosic fraction-induced niche differentiation within DIRB groups,which advanced our understanding of the ecology of DIRB in paddy soils under straw returning.
