title: Plant nitrogen-use strategy as a driver of rhizosphere archaeal and bacterial ammonia oxidiser abundance.
abstract: The influence of plants on archaeal (AOA) and bacterial (AOB) ammonia oxidisers (AO) is poorly understood. Higher microbial activity in the rhizosphere, including organic nitrogen (N) mineralisation, may stimulate both groups, while ammonia uptake by plants may favour AOA, considered to prefer lower ammonia concentration. We therefore hypothesised (i) higher AOA and AOB abundances in the rhizosphere than bulk soil and (ii) that AOA are favoured over AOB in the rhizosphere of plants with an exploitative strategy and high N demand, especially (iii) during early growth, when plant N uptake is higher. These hypotheses were tested by growing 20 grassland plants, covering a spectrum of resource-use strategies, and determining AOA and AOB amoA gene abundances, rhizosphere and bulk soil characteristics and plant functional traits. Joint Bayesian mixed models indicated no increase in AO in the rhizosphere, but revealed that AOA were more abundant in the rhizosphere of exploitative plants, mostly grasses, and less abundant under conservative plants. In contrast, AOB abundance in the rhizosphere and bulk soil depended on pH, rather than plant traits. These findings provide a mechanistic basis for plant-ammonia oxidiser interactions and for links between plant functional traits and ammonia oxidiser ecology.
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen, AB24 5UU, UK Laboratoire Ampère, CNRS UMR 5005, École Centrale de Lyon, University of Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France cecile.thion@ec-lyon.fr.
authors.forename: Cécile E
authors.initials: CE
authors.lastname: Thion
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen, AB24 5UU, UK.
authors.forename: Jessica D
authors.initials: JD
authors.lastname: Poirel
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen, AB24 5UU, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Cornulier
authors.affiliation: Faculty of Life Sciences, Michael Smith Building, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
authors.forename: Franciska T
authors.initials: FT
authors.lastname: De Vries
authors.affiliation: Faculty of Life Sciences, Michael Smith Building, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Bardgett
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen, AB24 5UU, UK.
authors.forename: James I
authors.initials: JI
authors.lastname: Prosser
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001105:Archaea / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001499:Bayes Theorem; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D010944:Plants / Q000378:metabolism / Q000382:microbiology*; D058441:Rhizosphere; D012988:Soil Microbiology
chemical_list: D000641:Ammonia; D009584:Nitrogen
keywords: ammonia-oxidising archaea; ammonia-oxidising bacteria; grasslands; plant traits; resource-use strategy; rhizosphere effect