Delineation of Paraburkholderia tuberum sensu stricto and description of Paraburkholderia podalyriae sp. nov. nodulating the South African legume Podalyria calyptrata.

Since the discovery of Paraburkholderia tuberum, an indigenous South African species and one of the first beta-rhizobia described, several other South African rhizobial Paraburkholderia species have been recognized. Here, we investigate the taxonomic status of 31 rhizobial isolates from the root nodules of diverse South African legume hosts in the Core Cape Subregion, which were initially identified as P. tuberum.

Paraburkholderia youngii sp. nov. and 'Paraburkholderia atlantica' - Brazilian and Mexican Mimosa-associated rhizobia that were previously known as Paraburkholderia tuberum sv. mimosae.

Previous studies have recognized South and Central/Latin American mimosoid legumes in the genera Mimosa, Piptadenia and Calliandra as hosts for various nodulating Paraburkholderia species. Several of these species have been validly named in the last two decades, e.g.

Diversity of endemic rhizobia on Christmas Island: Implications for agriculture following phosphate mining.

Given that phosphate supplies may diminish and become uneconomic to mine after 2020, there is a compelling need to develop alternative industries to support the population on Christmas Island. Former mine sites could be turned into productive agricultural land, however, large-scale commercial agriculture has never been attempted, and, given the uniqueness of the island, the diversity of rhizobia prior to introducing legumes needed evaluation. Therefore, 84 rhizobia isolates were obtained from nine different hosts, both crop and introduced legumes, located at seven sites across the island.

Symbiotic and non-symbiotic Paraburkholderia isolated from South African Lebeckia ambigua root nodules and the description of Paraburkholderia fynbosensis sp. nov.

Nine Gram-negative, rod-shaped bacteria were isolated from Lebeckia ambigua root nodules. All strains were able to nodulate and fix nitrogen with Lebeckia ambigua apart from WSM4178, WSM4181 and WSM4182. Based on the 16S rRNA gene phylogeny, all strains were closely related to Paraburkholderia species (98.

Horizontal Transfer of Symbiosis Genes within and Between Rhizobial Genera: Occurrence and Importance.

Rhizobial symbiosis genes are often carried on symbiotic islands or plasmids that can be transferred (horizontal transfer) between different bacterial species. Symbiosis genes involved in horizontal transfer have different phylogenies with respect to the core genome of their ‘host’. Here, the literature on legume⁻rhizobium symbioses in field soils was reviewed, and cases of phylogenetic incongruence between rhizobium core and symbiosis genes were collated.

Genetic diversity and symbiotic effectiveness of Phaseolus vulgaris-nodulating rhizobia in Kenya.

Phaseolus vulgaris (common bean) was introduced to Kenya several centuries ago but the rhizobia that nodulate it in the country remain poorly characterised. To address this gap in knowledge, 178 isolates recovered from the root nodules of P. vulgaris cultivated in Kenya were genotyped stepwise by the analysis of genomic DNA fingerprints, PCR-RFLP and 16S rRNA, atpD, recA and nodC gene sequences.

Complete Genome Sequence of ICMP 19535, a Highly Specific, Nitrogen-Fixing Symbiont of New Zealand Endemic spp.

We report here the complete genome sequence of ICMP 19535 This strain was isolated from root nodules and can nodulate and fix nitrogen with this host and also with , , and The genome consists of 8.05 Mb.

Bradyrhizobium centrolobii and Bradyrhizobium macuxiense sp. nov. isolated from Centrolobium paraense grown in soil of Amazonia, Brazil.

Thirteen Gram-negative, aerobic, motile with polar flagella, rod-shaped bacteria were isolated from root nodules of Centrolobium paraense Tul. grown in soils from the Amazon region of Brazil. Growth of strains was observed at temperature range 20-36 °C (optimal 28 °C), pH ranges 5-11 (optimal 6.

Symbiotic Burkholderia Species Show Diverse Arrangements of nif/fix and nod Genes and Lack Typical High-Affinity Cytochrome cbb3 Oxidase Genes.

Genome analysis of fourteen mimosoid and four papilionoid beta-rhizobia together with fourteen reference alpha-rhizobia for both nodulation (nod) and nitrogen-fixing (nif/fix) genes has shown phylogenetic congruence between 16S rRNA/MLSA (combined 16S rRNA gene sequencing and multilocus sequence analysis) and nif/fix genes, indicating a free-living diazotrophic ancestry of the beta-rhizobia. However, deeper genomic analysis revealed a complex symbiosis acquisition history in the beta-rhizobia that clearly separates the mimosoid and papilionoid nodulating groups. Mimosoid-nodulating beta-rhizobia have nod genes tightly clustered in the nodBCIJHASU operon, whereas papilionoid-nodulating Burkholderia have nodUSDABC and nodIJ genes, although their arrangement is not canonical because the nod genes are subdivided by the insertion of nif and other genes.

sp. nov., sp. nov., sp. nov., sp. nov. and sp. nov. isolated from root nodules.

In total, 31 strains of Gram-stain-negative, rod-shaped bacteria were isolated from root nodules and authenticated as rhizobia on this host. Based on 16S rRNA gene phylogeny, they were shown to belong to the genus , with the representative strains ICMP 19560, ICMP 19523, ICMP 19535, ICMP 19545 and ICMP 19512 being related most closely to SCAU7 (99.9-99.

High-quality permanent draft genome sequence of Bradyrhizobium sp. strain WSM1743 - an effective microsymbiont of an Indigofera sp. growing in Australia.

Bradyrhizobium sp. strain WSM1743 is an aerobic, motile, Gram-negative, non-spore-forming rod that can exist as a soil saprophyte or as a legume microsymbiont of an Indigofera sp. WSM1743 was isolated from a nodule recovered from the roots of an Indigofera sp.

High-quality permanent draft genome sequence of the Mimosa asperata - nodulating Cupriavidus sp. strain AMP6.

Cupriavidus sp. strain AMP6 is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from a root nodule of Mimosa asperata collected in Santa Ana National Wildlife Refuge, Texas, in 2005. Mimosa asperata is the only legume described so far to exclusively associates with Cupriavidus symbionts.

Burkholderia dipogonis sp. nov., isolated from root nodules of Dipogon lignosus in New Zealand and Western Australia.

Seven strains, ICMP 19430T, ICMP 19429, ICMP 19431, WSM4637, WSM4638, WSM4639 and WSM4640, were isolated from nitrogen-fixing nodules on roots of the invasive South African legume Dipogon lignosus (subfamily Papilionoideae, tribe Phaseoleae) in New Zealand and Western Australia, and their taxonomic positions were investigated by using a polyphasic approach. All seven strains grew at 10-37 °C (optimum, 25-30 °C), at pH 4.0-9.

High-quality permanent draft genome sequence of the Lebeckia - nodulating Burkholderia dilworthii strain WSM3556(T).

Burkholderia dilworthii strain WSM3556(T) is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from an effective N2-fixing root nodule of Lebeckia ambigua collected near Grotto Bay Nature Reserve, in the Western Cape of South Africa, in October 2004. This plant persists in infertile and deep sandy soils with acidic pH, and is therefore an ideal candidate for a perennial based agriculture system in Western Australia. WSM3556(T) thus represents a potential inoculant quality strain for L.

High-quality permanent draft genome sequence of Rhizobium sullae strain WSM1592; a Hedysarum coronarium microsymbiont from Sassari, Italy.

Rhizobium sullae strain WSM1592 is an aerobic, Gram-negative, non-spore-forming rod that was isolated from an effective nitrogen (N2) fixing root nodule formed on the short-lived perennial legume Hedysarum coronarium (also known as Sulla coronaria or Sulla). WSM1592 was isolated from a nodule recovered from H. coronarium roots located in Ottava, bordering Sassari, Sardinia in 1995.

Mesorhizobium waimense sp. nov. isolated from Sophora longicarinata root nodules and Mesorhizobium cantuariense sp. nov. isolated from Sophora microphylla root nodules.

In total 14 strains of Gram-stain-negative, rod-shaped bacteria were isolated from Sophora longicarinata and Sophora microphylla root nodules and authenticated as rhizobia on these hosts. Based on the 16S rRNA gene phylogeny, they were shown to belong to the genus Mesorhizobium, and the strains from S. longicarinata were most closely related to Mesorhizobium amorphae ACCC 19665T (99.

High-quality permanent draft genome sequence of Rhizobium leguminosarum bv. viciae strain GB30; an effective microsymbiont of Pisum sativum growing in Poland.

Rhizobium leguminosarum bv. viciae GB30 is an aerobic, motile, Gram-negative, non-spore-forming rod that can exist as a soil saprophyte or as a legume microsymbiont of Pisum sativum. GB30 was isolated in Poland from a nodule recovered from the roots of Pisum sativum growing at Janow.

High-quality permanent draft genome sequence of the Parapiptadenia rigida-nodulating Burkholderia sp. strain UYPR1.413.

Burkholderia sp. strain UYPR1.413 is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from a root nodule of Parapiptadenia rigida collected at the Angico plantation, Mandiyu, Uruguay, in December 2006.

High-quality permanent draft genome sequence of the Parapiptadenia rigida-nodulating Cupriavidus sp. strain UYPR2.512.

Cupriavidus sp. strain UYPR2.512 is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from a root nodule of Parapiptadenia rigida grown in soils from a native forest of Uruguay.

Ribosomal protein biomarkers provide root nodule bacterial identification by MALDI-TOF MS.

Accurate identification of soil bacteria that form nitrogen-fixing associations with legume crops is challenging given the phylogenetic diversity of root nodule bacteria (RNB). The labor-intensive and time-consuming 16S ribosomal RNA (rRNA) sequencing and/or multilocus sequence analysis (MLSA) of conserved genes so far remain the favored molecular tools to characterize symbiotic bacteria. With the development of mass spectrometry (MS) as an alternative method to rapidly identify bacterial isolates, we recently showed that matrix-assisted laser desorption ionization (MALDI) time-of-flight (TOF) can accurately characterize RNB found inside plant nodules or grown in cultures.

Diverse novel mesorhizobia nodulate New Zealand native Sophora species.

Forty eight rhizobial isolates from New Zealand (NZ) native Sophora spp. growing in natural ecosystems were characterised. Thirty eight isolates across five groups showed greatest similarity to Mesorhizobium ciceri LMG 14989(T) with respect to their 16S rRNA and concatenated recA, glnll and rpoB sequences.