title: Evidence of novel plant-species specific ammonia oxidizing bacterial clades in acidic South African fynbos soils.
abstract: Ammonia-oxidizing bacteria (AOB) are essential in the biogeochemical cycling of nitrogen as they catalyze the rate-limiting oxidation of ammonia into nitrite. Since their first isolation in the late 19th century, chemolithoautotrophic AOBs have been identified in a wide range of natural (e.g., soils, sediments, estuarine, and freshwaters) and man created or impacted habitats (e.g., wastewater treatment plants and agricultural soils). However, little is known on the plant-species association of AOBs, particularly in the nutrient-starved fynbos terrestrial biome. In this study, we evaluated the diversity of AOBs in the plant canopy of three South African fynbos-specific plant species, namely Leucadendron xanthoconus, Leucospermum truncatulum and Leucadendron microcephalum, through the construction of amoA-gene clone libraries. Our results clearly demonstrate that plant-species specific and monophyletic AOB clades are present in fynbos canopy soils.
authors.affiliation: Center for Microbial Ecology and Genomics, Genomics Research Institute, Department of Genetics, University of Pretoria, Pretoria, South Africa.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Ramond
authors.affiliation: Department of Biotechnology, Dr. John Garang Memorial University of Science and Technology, Bor Town, Jonglei State, South Sudan.
authors.forename: Joseph D W
authors.initials: JD
authors.lastname: Lako
authors.affiliation: Council for Scientific and Industrial Research (CSIR), South Africa.
authors.forename: William H L
authors.initials: WH
authors.lastname: Stafford
authors.affiliation: Department of Biotechnology, Institute for Microbial Biotechnology and Metagenomics (IMBM), University of the Western Cape, Cape Town, South Africa.
authors.forename: Marla I
authors.initials: MI
authors.lastname: Tuffin
authors.affiliation: Center for Microbial Ecology and Genomics, Genomics Research Institute, Department of Genetics, University of Pretoria, Pretoria, South Africa.
authors.forename: Don A
authors.initials: DA
authors.lastname: Cowan
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D020562:Betaproteobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D044822:Biodiversity; D015723:Gene Library; D058465:Nitrification; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D039105:Proteaceae / Q000382:microbiology*; D058441:Rhizosphere; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D013019:South Africa
chemical_list: D012987:Soil; D000641:Ammonia; D010088:Oxidoreductases; C045582:ammonia monooxygenase; D009584:Nitrogen
keywords: Ammonia oxidizers; Fynbos soil; Plant-microbe interactions; Proteaceae family; amoA-gene diversity