Effect of nitrogen and waterlogging on denitrifier gene abundance, community structure and activity in the rhizosphere of wheat. Issue 3 (17th October 2012)

• Record Type: Journal Article
• Authors: Hamonts, Kelly; Clough, Tim J.; Stewart, Alison; Clinton, Peter W.; Richardson, Alan E.; Wakelin, Steven A.; O'Callaghan, Maureen; Condron, Leo M.
• Is Part Of: FEMS microbiology ecology. Volume 83:Issue 3(2013)
• Page Start: 568
• Page End: 584
• Publication Date: 2012-10-17
• Subjects: Microbial ecology -- Periodicals; Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1574-6941.12015
• Languages: English
• ISSNs: 0168-6496

Abstract

<abstract abstract-type="main" id="fem12015-abs-0001"> <title>Abstract</title> <p>Microbial denitrification plays a key role in determining the availability of soil nitrogen (N) to plants. However, factors influencing the structure and function of denitrifier communities in the rhizosphere remain unclear. Waterlogging can result in root anoxia and increased denitrification, leading to significant N loss from soil and potential nitrous oxide (N<sub>2</sub>O) emissions. This study investigated denitrifier gene abundance, community structure and activity in the rhizosphere of wheat in response to anoxia and N limitation. Denitrifier community structure in the rhizosphere differed from that in bulk soil, and denitrifier gene copy numbers (<italic>nirS</italic>, <italic>nirK</italic>, <italic>nosZ</italic>) and potential denitrification activity were greater in the rhizosphere. Anoxia and N limitation, and in particular a combination of both, reduced the magnitude of this effect on gene abundance (in particular <italic>nirS</italic>) and activity, with N limitation having greater impact than waterlogging in rhizosphere soil, in contrast to bulk soil where the impact of waterlogging was greater. Increased N supply to anoxic plants improved plant health and increased rhizosphere soil pH, which resulted in enhanced reduction of N<sub>2</sub>O. Both anoxia and N limitation significantly influenced the structure and function of denitrifier communities in the rhizosphere, with reduced root‐derived carbon postulated to play an important role.</p> </abstract>