Dandie, C.E.Burton, D.L.Zebarth, B.J.Henderson, S.L.Trevors, J.T.Goyer, C.2025-12-172025-12-172008Applied and Environmental Microbiology, 2008; 74(19):5997-60050099-22401098-5336https://hdl.handle.net/1959.8/152642Link to a related website: http://europepmc.org/articles/pmc2565952?pdf=render, Open Access via Unpaywall<jats:title>ABSTRACT</jats:title> <jats:p> This study measured total bacterial and denitrifier community abundances over time in an agricultural soil cropped to potatoes ( <jats:italic>Solanum tuberosum</jats:italic> L.) by using quantitative PCR. Samples were collected on 10 dates from spring to autumn and from three spatial locations: in the potato “hill” between plants (H), close to the plant (H <jats:sub>p</jats:sub> ), and in the “furrow” (F). The denitrification rates, N <jats:sub>2</jats:sub> O emissions, and environmental parameters were also measured. Changes in denitrifier abundance over time and spatial location were small (1.7- to 2.7-fold for the <jats:italic>nirK</jats:italic> , <jats:italic>nosZ</jats:italic> , and <jats:italic>cnorB</jats:italic> <jats:sub>B</jats:sub> guilds), whereas the <jats:italic>cnorB</jats:italic> <jats:sub>P</jats:sub> community ( <jats:italic>Pseudomonas mandelii</jats:italic> and closely related spp.) showed an ∼4.6-fold change. The seasonal patterns of denitrifier gene numbers varied with the specific community: lower <jats:italic>nosZ</jats:italic> gene numbers in April and May than in June and July, higher <jats:italic>cnorB</jats:italic> <jats:sub>P</jats:sub> gene numbers in May and June than in March and April and September and November, higher <jats:italic>nirK</jats:italic> gene numbers in early spring than in late autumn, and no change in <jats:italic>cnorB</jats:italic> <jats:sub>B</jats:sub> gene numbers. Gene numbers were higher for the H <jats:sub>p</jats:sub> than the H location for the <jats:italic>nosZ</jats:italic> and <jats:italic>nirK</jats:italic> communities and for the <jats:italic>cnorB</jats:italic> <jats:sub>P</jats:sub> community on individual dates, presumably indicating an effect of the plant on denitrifier abundance. Higher <jats:italic>cnorB</jats:italic> <jats:sub>P</jats:sub> gene numbers for the H location than the F location and for <jats:italic>nosZ</jats:italic> and <jats:italic>cnorB</jats:italic> <jats:sub>B</jats:sub> on individual dates reflect the effect of spatial location on abundance. Denitrifier abundance changes were not related to any environmental parameter, although a weak relationship exists between <jats:italic>cnorB</jats:italic> <jats:sub>P</jats:sub> gene numbers, extractable organic carbon values, and temperature. Denitrification and N <jats:sub>2</jats:sub> O emissions were mostly regulated by inorganic nitrogen availability and water-filled pore space but were uncoupled from denitrifier community abundances measured in this system. </jats:p>enCopyright 2008 American Society for Microbiologyammonia-oxidizing bacterian2o emissionsterrestrial ecosystemoxide reductasesoil-moistureribosomal-rnanosz genesnitrogennitratepotatoJournal article10.1128/AEM.00441-082-s2.0-54449086033