Closed genomes of commercial inoculant rhizobia provide a blueprint for management of legume inoculation.

Unlabelled: Rhizobia are soil bacteria capable of establishing symbiosis within legume root nodules, where they reduce atmospheric N into ammonia and supply it to the plant for growth. Australian soils often lack rhizobia compatible with introduced agricultural legumes, so inoculation with exotic strains has become a common practice for over 50 years. While extensive research has assessed the N-fixing capabilities of these inoculants, their genomics, taxonomy, and core and accessory gene phylogeny are poorly characterized.

Complete genome sequence of bv. viciae SRDI969, an acid-tolerant, efficient N-fixing microsymbiont of .

We report the complete genome sequence of bv. viciae SRDI969, an acid-tolerant, efficient nitrogen-fixing microorganism of . The 6.

Competition in the - symbiosis and the role of resident soil rhizobia in determining the outcomes of inoculation.

Background And Aims: Inoculation of legumes with effective N-fixing rhizobia is a common practice to improve farming profitability and sustainability. To succeed, inoculant rhizobia must overcome competition for nodulation by resident soil rhizobia that fix N ineffectively. In Kenya, where (common bean) is inoculated with highly effective CIAT899 from Colombia, response to inoculation is low, possibly due to competition from ineffective resident soil rhizobia.

The putative vacuolar processing enzyme gene TaVPE3cB is a candidate gene for wheat stem pith-thickness.

The vacuolar processing enzyme gene TaVPE3cB is identified as a candidate gene for a QTL of wheat pith-thickness on chromosome 3B by BSR-seq and differential expression analyses. The high pith-thickness (PT) of the wheat stem could greatly enhance stem mechanical strength, especially the basal internodes which support the heavier upper part, such as upper stems, leaves and spikes. A QTL for PT in wheat was previously discovered on 3BL in a double haploid population of 'Westonia' × 'Kauz'.

Current Progress and Future Prospect of Wheat Genetics Research towards an Enhanced Nitrogen Use Efficiency.

To improve the yield and quality of wheat is of great importance for food security worldwide. One of the most effective and significant approaches to achieve this goal is to enhance the nitrogen use efficiency (NUE) in wheat. In this review, a comprehensive understanding of the factors involved in the process of the wheat nitrogen uptake, assimilation and remobilization of nitrogen in wheat were introduced.

Physiological and cannabinoid responses of hemp () to rock phosphate dust under tropical conditions.

Growing a high-value crop such as industrial hemp (Cannabis sativa L.) in post-mining environments is economically and environmentally attractive but faces a range of biotic and abiotic challenges. An opportunity to investigate the cultivation of C.

Semi-quantitative analysis of cannabinoids in hemp (Cannabis sativa L.) using gas chromatography coupled to mass spectrometry.

Background: Hemp (Cannabis sativa L.) is a producer of cannabinoids. These organic compounds are of increasing interest due to their potential applications in the medicinal field.

sp. nov., sp. nov., sp. nov. and sp. nov., symbionts of different leguminous plants of Western Australia and South Africa and definition of three novel symbiovars.

is a heterogeneous bacterial genus capable of establishing symbiotic associations with a broad range of legume hosts, including species of economic and environmental importance. This study was focused on the taxonomic and symbiovar definition of four strains - CNPSo 4026, WSM 1704, WSM 1738 and WSM 4400 - previously isolated from nodules of legumes in Western Australia and South Africa. The 16S rRNA gene phylogenetic tree allocated the strains to the supergroup.

sp. nov., sp. nov. and sp. nov., isolated from a biodiversity hotspot of the genus in Western Australia.

Strains of the genus associated with agronomically important crops such as soybean () are increasingly studied; however, information about symbionts of wild species is scarce. Australia is a genetic centre of wild species and we performed a polyphasic analysis of three strains-CNPSo 4010, CNPSo 4016, and CNPSo 4019-trapped from Western Australian soils with , and , respectively. The phylogenetic tree of the 16S rRNA gene clustered all strains into the superclade; strains CNPSo 4010 and CNPSo 4016 had CCBAU 10071 as the closest species, whereas strain CNPSo 4019 was closer to LMG 18230.

Evolution of diverse effective N-fixing microsymbionts of following horizontal transfer of the CC1192 symbiosis integrative and conjugative element.

Rhizobia are soil bacteria capable of forming N-fixing symbioses with legumes, with highly effective strains often selected in agriculture as inoculants to maximize symbiotic N fixation. When rhizobia in the genus have been introduced with exotic legumes into farming systems, horizontal transfer of symbiosis Integrative and Conjugative Elements (ICEs) from the inoculant strain to soil bacteria has resulted in the evolution of ineffective N-fixing rhizobia that are competitive for nodulation with the target legume. In Australia, (chickpea) has been inoculated since the 1970's with sv.

sp. nov., sp. nov. and sp. nov., isolated from nodules of legumes indigenous to Western Australia.

The genus is considered as the probable ancestor lineage of all rhizobia, broadly spread in a variety of ecosystems and with remarkable diversity. A polyphasic study was performed to characterize and clarify the taxonomic position of eight bradyrhizobial strains isolated from indigenous legumes to Western Australia. As expected for the genus, the 16S rRNA gene sequences were highly conserved, but the results of multilocus sequence analysis with four housekeeping genes (, and ) confirmed three new distinct clades including the following strains: (1) WSM 1744, WSM 1736 and WSM 1737; (2) WSM 1791 and WSM 1742; and (3) WSM 1741, WSM 1735 and WSM 1790.

Characterization of Bradyrhizobium strains indigenous to Western Australia and South Africa indicates remarkable genetic diversity and reveals putative new species.

Bradyrhizobium are N-fixing microsymbionts of legumes with relevant applications in agricultural sustainability, and we investigated the phylogenetic relationships of conserved and symbiotic genes of 21 bradyrhizobial strains. The study included strains from Western Australia (WA), isolated from nodules of Glycine spp. the country is one genetic center for the genus and from nodules of other indigenous legumes grown in WA, and strains isolated from forage Glycine sp.

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.

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.

Sequential induction of three recombination directionality factors directs assembly of tripartite integrative and conjugative elements.

Tripartite integrative and conjugative elements (ICE3) are a novel form of ICE that exist as three separate DNA regions integrated within the genomes of Mesorhizobium spp. Prior to conjugative transfer the three ICE3 regions of M. ciceri WSM1271 ICEMcSym1271 combine and excise to form a single circular element.

Transitioning from phosphate mining to agriculture: Responses to urea and slow release fertilizers for Sorghum bicolor.

Globally, land-use transition from mining to agriculture is becoming increasingly attractive and necessary for many reasons. However, low levels of necessary plant nutrients, and high levels of heavy metals, can hamper plant growth, affecting yield, and potentially, food safety. In post-phosphate mining substrates, for example, nitrogen (N) is a key limiting nutrient, and, although legumes are planted prior to cereals, N supplementation is still necessary.

Complete Genome Sequence of bv. biserrulae WSM1497, an Efficient Nitrogen-Fixing Microsymbiont of the Forage Legume .

We report here the complete genome sequence of bv. biserrulae strain WSM1497, the efficient nitrogen-fixing microsymbiont and commercial inoculant in Australia of the forage legume The genome consists of 7.2 Mb distributed across a single chromosome (6.

Evolutionary persistence of tripartite integrative and conjugative elements.

Integrative and conjugative elements (ICEs) are generally regarded as regions of contiguous DNA integrated within a bacterial genome that are capable of excision and horizontal transfer via conjugation. We recently characterized a unique group of ICEs present in Mesorhizobium spp., which exist as three entirely separate but inextricably linked chromosomal regions termed α, β and γ.

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.

Assembly and transfer of tripartite integrative and conjugative genetic elements.

Integrative and conjugative elements (ICEs) are ubiquitous mobile genetic elements present as "genomic islands" within bacterial chromosomes. Symbiosis islands are ICEs that convert nonsymbiotic mesorhizobia into symbionts of legumes. Here we report the discovery of symbiosis ICEs that exist as three separate chromosomal regions when integrated in their hosts, but through recombination assemble as a single circular ICE for conjugative transfer.

Complete Genome Sequence of Mesorhizobium ciceri Strain CC1192, an Efficient Nitrogen-Fixing Microsymbiont of Cicer arietinum.

We report the complete genome sequence of Mesorhizobium ciceri strain CC1192, an efficient nitrogen-fixing microsymbiont of Cicer arietinum (chickpea). The genome consists of 6.94 Mb distributed between a single chromosome (6.

Complete Genome Sequence of Mesorhizobium ciceri bv. biserrulae Strain WSM1284, an Efficient Nitrogen-Fixing Microsymbiont of the Pasture Legume Biserrula pelecinus.

We report the complete genome sequence of Mesorhizobium ciceri bv. biserrulae strain WSM1284, a nitrogen-fixing microsymbiont of the pasture legume Biserrula pelecinus The genome consists of 6.88 Mb distributed between a single chromosome (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.

High-quality permanent draft genome sequence of Ensifer medicae strain WSM244, a microsymbiont isolated from Medicago polymorpha growing in alkaline soil.

Ensifer medicae WSM244 is an aerobic, motile, Gram-negative, non-spore-forming rod that can exist as a soil saprophyte or as a legume microsymbiont of Medicago species. WSM244 was isolated in 1979 from a nodule recovered from the roots of the annual Medicago polymorpha L. growing in alkaline soil (pH 8.