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Modularity of nitrogen‐oxide reducing soil bacteria: linking phenotype to genotype
Author(s) -
Roco Constance A.,
Bergaust Linda L.,
Bakken Lars R.,
Yavitt Joseph B.,
Shapleigh James P.
Publication year - 2017
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.13250
Subject(s) - nitrite reductase , biology , nitrous oxide reductase , nitrate reductase , bacteria , denitrifying bacteria , reductase , gene , nitrate , genome , genetics , soil microbiology , denitrification , nitrogen , biochemistry , enzyme , ecology , chemistry , organic chemistry
Summary Model denitrifiers convertNO 3 −to N 2 , but it appears that a significant fraction of natural populations are truncated, conducting only one or two steps of the pathway. To better understand the diversity of partial denitrifiers in soil and whether discrepancies arise between the presence of known N‐oxide reductase genes and phenotypic features, bacteria able to reduceNO 3 −toNO 2 −were isolated from soil, N‐oxide gas products were measured for eight isolates, and six were genome sequenced. Gas phase analyses revealed that two were complete denitrifiers, which genome sequencing corroborated. The remaining six accumulated NO and N 2 O to varying degrees and genome sequencing of four indicated that two isolates held genes encoding nitrate reductase as the only dissimilatory N‐oxide reductase, one contained genes for both nitrate and nitric oxide reductase, and one had nitrate and nitrite reductase. The results demonstrated that N‐oxide production was not always predicted by the genetic potential and suggested that partial denitrifiers could be readily isolated among soil bacteria. This supported the hypothesis that each N‐oxide reductase could provide a selectable benefit on its own, and therefore, reduction of nitrate to dinitrogen may not be obligatorily linked to complete denitrifiers but instead a consequence of a functionally diverse community.