title: Specific Microbial Communities Associate with the Rhizosphere of Welwitschia mirabilis, a Living Fossil.
abstract: Welwitschia mirabilis is an ancient and rare plant distributed along the western coast of Namibia and Angola. Several aspects of Welwitschia biology and ecology have been investigated, but very little is known about the microbial communities associated with this plant. This study reports on the bacterial and fungal communities inhabiting the rhizosphere of W. mirabilis and the surrounding bulk soil. Rhizosphere communities were dominated by sequences of Alphaproteobacteria and Euromycetes, while Actinobacteria, Alphaproteobacteria, and fungi of the class Dothideomycetes jointly dominated bulk soil communities. Although microbial communities within the rhizosphere and soil samples were highly variable, very few "species" (OTUs defined at a 97% identity cut-off) were shared between these two environments. There was a small 'core' rhizosphere bacterial community (formed by Nitratireductor, Steroidobacter, Pseudonocardia and three Phylobacteriaceae) that together with Rhizophagus, an arbuscular mycorrhizal fungus, and other putative plant growth-promoting microbes may interact synergistically to promote Welwitschia growth.
authors.affiliation: Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa.
authors.forename: Angel
authors.identifier: http://orcid.org/0000-0003-0439-9605
authors.initials: A
authors.lastname: Valverde
authors.affiliation: Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa.
authors.forename: Pieter
authors.initials: P
authors.lastname: De Maayer
authors.affiliation: Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa.
authors.forename: Tanzelle
authors.initials: T
authors.lastname: Oberholster
authors.affiliation: Namib Ecological Restoration and Monitoring Unit, Gobabeb Research and Training Centre, Walvis Bay, Namibia.|SAEON Arid Lands Node, Hadison Park, Kimberly, South Africa.
authors.forename: Joh
authors.initials: J
authors.lastname: Henschel
authors.affiliation: Swakop Uranium, Swakopmund, Namibia.
authors.forename: Michele K
authors.initials: MK
authors.lastname: Louw
authors.affiliation: Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa.
authors.forename: Don
authors.initials: D
authors.lastname: Cowan
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics; D005580:Fossils / Q000382:microbiology*; D039282:Mirabilis / Q000235:genetics / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D058441:Rhizosphere; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D012336:RNA, Ribosomal, 16S; D012987:Soil