Distinct Bradyrhizbium communities nodulate legumes native to temperate and tropical monsoon Australia

Stępkowski, Tomasz; Watkin, Elizabeth; McInnes, Alison; Gurda, Dorota; Gracz, Joanna; Steenkamp, Emma Theodora

doi:10.1016/j.ympev.2011.12.020

Cited by 46 publications

(33 citation statements)

References 96 publications

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“…Thus, either many of our Namibian isolates may represent local genotypes or they belong to genotypes widespread in, and potentially restricted to, sub-Saharan countries. Similar results were observed in a recent survey on Australian bradyrhizobia (64), where it was found that most isolates were distinct from non-Australian bradyrhizobia, presumably due to geographic isolation and plant endemicity.…”

Section: Pachyrhizisupporting

confidence: 89%

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Rhizobia Indigenous to the Okavango Region in Sub-Saharan Africa: Diversity, Adaptations, and Host Specificity

Grönemeyer

Kulkarni

Hölscher

et al. 2014

Appl Environ Microbiol

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The rhizobial community indigenous to the Okavango region has not yet been characterized. The isolation of indigenous rhizobia can provide a basis for the formulation of a rhizobial inoculant. Moreover, their identification and characterization contribute to the general understanding of species distribution and ecology. Isolates were obtained from nodules of local varieties of the pulses cowpea, Bambara groundnut, peanut, hyacinth bean, and common bean. Ninety-one of them were identified by BOX repetitive element PCR (BOX-PCR) and sequence analyses of the 16S-23S rRNA internally transcribed spacer (ITS) and the recA, glnII, rpoB, and nifH genes. A striking geographical distribution was observed. Bradyrhizobium pachyrhizi dominated at sampling sites in Angola which were characterized by acid soils and a semihumid climate. Isolates from the semiarid sampling sites in Namibia were more diverse, with most of them being related to Bradyrhizobium yuanmingense and Bradyrhizobium daqingense. Host plant specificity was observed only for hyacinth bean, which was nodulated by rhizobia presumably representing yet-undescribed species. Furthermore, the isolates were characterized with respect to their adaptation to high temperatures, drought, and local host plants. The adaptation experiments revealed that the Namibian isolates shared an exceptionally high temperature tolerance, but none of the isolates showed considerable adaptation to drought. Moreover, the isolates' performance on different local hosts showed variable results, with most Namibian isolates inducing better nodulation on peanut and hyacinth bean than the Angolan strains. The local predominance of distinct genotypes implies that indigenous strains may exhibit a better performance in inoculant formulations.T he catchment area of the Okavango River extends across parts of the three sub-Saharan African countries of Angola, Namibia, and Botswana and is mainly characterized by smallholder and subsistence farming. Since cultivation techniques remain underdeveloped, e.g., in terms of irrigation and the application of agrochemicals or rhizobial inoculants, local farmers are confronted with low yields and decreasing soil fertilities (1). Pulses like cowpea (Vigna unguiculata), Bambara groundnut (Vigna subterranea), peanut (Arachis hypogaea), hyacinth bean (Lablab purpureus), and common bean (Phaseolus vulgaris) are cultivated and occasionally intercropped, but natural nodulation rates are often low (2), presumably due to a seasonal reduction of the rhizobial population caused by drought and heat. Thus, nitrogen input via symbiotic N 2 fixation might be very limited.Field-grown cowpea plants in Ghana have been reported to fix more than 200 kg N/ha (89% of plant N) (3). In contrast, values of only 4 to 29 kg N-fixed/ha (15 to 56% of plant N) were observed in semiarid southwestern Zimbabwe (4). In such areas, the application of a rhizobial inoculant may thus hold the potential to increase plant nutrition and soil fertility. Many effective rhizobial strains have been identif...

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Section: Pachyrhizisupporting

confidence: 89%

“…Since their physiology is typical of the genus Bradyrhizobium, they may represent a novel bradyrhizobial lineage apart from the established B. japonicum and B. elkanii lineages. The existence of more such lineages was also indicated in a recent study (64).…”

Section: Pachyrhizimentioning

confidence: 55%

Rhizobia Indigenous to the Okavango Region in Sub-Saharan Africa: Diversity, Adaptations, and Host Specificity

Grönemeyer

Kulkarni

Hölscher

et al. 2014

Appl Environ Microbiol

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“…These two broad lineages have been detected in most prior phylogenetic analyses of Bradyrhizobium (e.g. Moulin et al, 2004;Vinuesa et al, 2008;Ramírez-Bahena et al, 2009;Rivas et al, 2009;Stepkowski et al, 2012). Both superclades were represented in all eight of the regions sampled (Fig.…”

Section: Bradyrhizobium Phylogenetic Relationshipssupporting

confidence: 54%

“…However, the wide variation in host breadth among rhizobia has made this a challenging problem to analyse. Rhizobial groups show complex patterns of distribution across legume taxa (Vinuesa et al, 2005;Stepkowski et al, 2007Stepkowski et al, , 2012Nzoué et al, 2009). For any given bacterial lineage, it is thus unclear whether the major limiting factor affecting geographical spread might involve regional differentiation of legume communities or non-symbiotic factors such as physical habitat variables and dispersal limitation.…”

Section: Introductionmentioning

confidence: 99%

Phylogenetic clustering of Bradyrhizobium symbionts on legumes indigenous to North America

Koppell

Parker

2012

Microbiology

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To analyse determinants of biogeographic structure in members of the genus Bradyrhizobium, isolates were obtained from 41 legume genera, originating from North American sites spanning 48.5 6 of latitude (Alaska to Panama). Sequencing of portions of six gene loci (3674 bp) in 203 isolates showed that there was only a weak trend towards higher nucleotide diversity in tropical regions. Phylogenetic relationships for nifD, in the symbiosis island region of the Bradyrhizobium chromosome, conflicted substantially with a tree inferred for five housekeeping gene loci. For both nifD and housekeeping gene trees, bacteria from each region were significantly more similar, on average, than would be expected if the source location was permuted at random on the tree. Within-region permutation tests also showed that bacteria clustered significantly on particular host plant clades at all levels in the phylogeny of legumes (from genus up to subfamily). Nevertheless, some bacterial groups were dispersed across multiple regions and were associated with diverse legume host lineages. These results indicate that migration, horizontal gene transfer and host interactions have all influenced the geographical divergence of Bradyrhizobium populations on a continental scale.

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“…The current Mesorhizobium diversity from fynbos Psoralea has been placed in a separate cluster unrelated to known 16S rRNA or nodA gene types from other African localities, suggesting rhizobial strains restricted to the Cape region. The Bradyrhizobium isolates from the Malawian soils, however, were closely related to B. elkanii and are geographically widespread and able to nodulate a broad range of legumes from different continents (65,(84)(85)(86)(87). In a recent study by M. A. Parker (88), a phylogenetic analysis of a broad sampling of Bradyrhizobium strains from diverse plant groups provided evidence of a broad host range of most bradyrhizobial lineages, including B. elkanii, that are associated with diverse legume tribes.…”

Section: Bradyrhizobiumafrica and South Americamentioning

confidence: 99%

Biogeographical Patterns of Legume-Nodulating Burkholderia spp.: from African Fynbos to Continental Scales

Lemaire

Chimphango

Stirton

et al. 2016

Appl Environ Microbiol

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Rhizobia of the genus Burkholderia have large-scale distribution ranges and are usually associated with South African papilionoid and South American mimosoid legumes, yet little is known about their genetic structuring at either local or global geographic scales. To understand variation at different spatial scales, from individual legumes in the fynbos (South Africa) to a global context, we analyzed chromosomal (16S rRNA, recA) and symbiosis (nifH, nodA, nodC) gene sequences. We showed that the global diversity of nodulation genes is generally grouped according to the South African papilionoid or South American mimosoid subfamilies, whereas chromosomal sequence data were unrelated to biogeography. While nodulation genes are structured on a continental scale, a geographic or host-specific distribution pattern was not detected in the fynbos region. In host range experiments, symbiotic promiscuity of Burkholderia tuberum STM678 T and B. phymatum STM815 T was discovered in selected fynbos species. Finally, a greenhouse experiment was undertaken to assess the ability of mimosoid (Mimosa pudica) and papilionoid (Dipogon lignosus, Indigofera filifolia, Macroptilium atropurpureum, and Podalyria calyptrata) species to nodulate in South African (fynbos) and Malawian (savanna) soils. While the Burkholderia-philous fynbos legumes (D. lignosus, I. filifolia, and P. calyptrata) nodulated only in their native soils, the invasive neotropical species M. pudica did not develop nodules in the African soils. The fynbos soil, notably rich in Burkholderia, seems to retain nodulation genes compatible with the local papilionoid legume flora but is incapable of nodulating mimosoid legumes that have their center of diversity in South America. IMPORTANCEThis study is the most comprehensive phylogenetic assessment of root-nodulating Burkholderia and investigated biogeographic and host-related patterns of the legume-rhizobial symbiosis in the South African fynbos biome, as well as at global scales, including native species from the South American Caatinga and Cerrado biomes. While a global investigation of the rhizobial diversity revealed distinct nodulation and nitrogen fixation genes among South African and South American legumes, regionally distributed species in the Cape region were unrelated to geographic and host factors.

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Distinct Bradyrhizbium communities nodulate legumes native to temperate and tropical monsoon Australia

Cited by 46 publications

References 96 publications

Rhizobia Indigenous to the Okavango Region in Sub-Saharan Africa: Diversity, Adaptations, and Host Specificity

Rhizobia Indigenous to the Okavango Region in Sub-Saharan Africa: Diversity, Adaptations, and Host Specificity

Phylogenetic clustering of Bradyrhizobium symbionts on legumes indigenous to North America

Biogeographical Patterns of Legume-Nodulating Burkholderia spp.: from African Fynbos to Continental Scales

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