title: Symbiotic diversity, specificity and distribution of rhizobia in native legumes of the Core Cape Subregion (South Africa).
abstract: Rhizobial diversity and host preferences were assessed in 65 native Fynbos legumes of the papilionoid legume tribes Astragaleae, Crotalarieae, Genisteae, Indigofereae, Millettieae, Phaseoleae, Podalyrieae, Psoraleeae and Sesbanieae. Sequence analyses of chromosomal 16S rRNA, recA, atpD and symbiosis-related nodA, nifH genes in parallel with immunogold labelling assays identified the symbionts as alpha- (Azorhizobium, Bradyrhizobium, Ensifer, Mesorhizobium and Rhizobium) and beta-rhizobial (Burkholderia) lineages with the majority placed in the genera Mesorhizobium and Burkholderia showing a wide range of host interactions. Despite a degree of symbiotic promiscuity in the tribes Crotalarieae and Indigofereae nodulating with both alpha- and beta-rhizobia, Mesorhizobium symbionts appeared to exhibit a general host preference for the tribe Psoraleeae, whereas Burkholderia prevailed in the Podalyrieae. Although host genotype was the main factor determining rhizobial diversity, ecological factors such as soil acidity and site elevation were positively correlated with genetic variation within Mesorhizobium and Burkholderia, respectively, indicating an interplay of host and environmental factors on the distribution of Fynbos rhizobia.
authors.affiliation: Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa Plant Conservation and Population Biology, KU Leuven, Kasteelpark Arenberg 31, PO Box 2435, 3001 Heverlee, Belgium benny.lemaire@bio.kuleuven.be.
authors.forename: Benny
authors.initials: B
authors.lastname: Lemaire
authors.affiliation: Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa.
authors.forename: Oscar
authors.initials: O
authors.lastname: Dlodlo
authors.affiliation: Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa.
authors.forename: Samson
authors.initials: S
authors.lastname: Chimphango
authors.affiliation: Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa.
authors.forename: Charles
authors.initials: C
authors.lastname: Stirton
authors.affiliation: Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK.
authors.forename: Brian
authors.initials: B
authors.lastname: Schrire
authors.affiliation: Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
authors.forename: James S
authors.initials: JS
authors.lastname: Boatwright
authors.affiliation: Plant Conservation and Population Biology, KU Leuven, Kasteelpark Arenberg 31, PO Box 2435, 3001 Heverlee, Belgium.
authors.forename: Olivier
authors.initials: O
authors.lastname: Honnay
authors.affiliation: Plant Conservation and Population Biology, KU Leuven, Kasteelpark Arenberg 31, PO Box 2435, 3001 Heverlee, Belgium Naturalis Biodiversity Center, Leiden University, 2300 RA Leiden, The Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: Smets
authors.affiliation: Division of Plant Sciences, University of Dundee at JHI, Dundee DD2 5DA, UK.
authors.forename: Janet
authors.initials: J
authors.lastname: Sprent
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
authors.forename: Euan K
authors.initials: EK
authors.lastname: James
authors.affiliation: Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa.
authors.forename: Abraham M
authors.initials: AM
authors.lastname: Muasya
mesh_terms: D000217:Acyltransferases / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D044822:Biodiversity; D020369:Bradyrhizobium / Q000235:genetics; D019117:Burkholderia / Q000145:classification / Q000235:genetics; D007887:Fabaceae / Q000382:microbiology*; D058507:Host Specificity; D059128:Mesorhizobium / Q000145:classification / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics; D012231:Rhizobium / Q000145:classification / Q000235:genetics*; D053204:Root Nodules, Plant / Q000382:microbiology*; D013019:South Africa; D013559:Symbiosis / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S; D010088:Oxidoreductases; C029130:nitrogenase reductase; D000217:Acyltransferases; C060770:NodA protein, Rhizobiales; D011938:Rec A Recombinases
keywords: Burkholderia; Fynbos legumes; Mesorhizobium; host preference; in situ immunogold labelling; root nodulation