Rhizobium paranaense sp. nov., an effective N2-fixing symbiont of common bean (Phaseolus vulgaris L.) with broad geographical distribution in Brazil

Abstract

Nitrogen (N), the nutrient most required for plant growth, is key for good yield of agriculturally important crops. Common bean (Phaseolus vulgaris L.) can benefit from bacteria collectively called rhizobia, which are capable of fixing atmospheric nitrogen (N 2 ) in root nodules and supplying it to the plant. Common bean is amongst the most promiscuous legume hosts; several described species, in addition to putative novel ones have been reported as able to nodulate this legume, although not always effectively in terms of fixing N 2 . In this study, we present data indicating that Brazilian strains PRF 35 T , PRF 54, CPAO 1135 and H 52, currently classified as Rhizobium tropici, represent a novel species symbiont of common bean. Morphological, physiological and biochemical properties differentiate these strains from other species of the genus Rhizobium, as do BOX-PCR profiles (less than 60 % similarity), multilocus sequence analysis with recA, gyrB and rpoA (less than 96.4 % sequence similarity), DNA-DNA hybridization (less than 50 % DNA-DNA relatedness), and average nucleotide identity of whole genomes (less than 92.8.%). The novel species is effective in nodulating and fixing N 2 with P. vulgaris, Leucaena leucocephala and Leucaena esculenta. We propose the name Rhizobium paranaense sp. nov. for this novel taxon, with strain PRF 35 T (5CNPSo 120 T 5LMG 27577 T 5IPR-Pv 1249 T ) as the type strain.

Rhizobium ecuadorense sp. nov., an indigenous N2-fixing symbiont of the Ecuadorian common bean (Phaseolus vulgaris L.) genetic pool

“…phaseoli , R. gallicum , R. lusitanum , R. pisi , R. freirei , R. mesoamericanum , R. paranaense ) and ineffective ( R. giardinii sv. giardinii and R. miluonense ) symbioses (Dall'Agnol et al , 2014). However, there are relatively few studies regarding common bean–rhizobia coevolution in centres of origin/domestication of the legume.…”

New Native Rhizobia Strains for Inoculation of Common Bean in the Brazilian Savanna

“…giardinii and bv. phaseoli) (Amarger et al, 1997), R. leucaenae (Ribeiro et al, 2012), R. freirei (Dall'Agnol et al, 2013), and R. paranaense (Dall'Agnol et al, 2014). An important feature of the bean microsymbiont rhizobia genome is the presence of DNA repeated sequences found in the symbiotic plasmid regions, pSym containing the structural nitrogenase gene, nif, or the nodulation gene, nod (Girard et al, 1991;Segovia et al, 1993).…”

Isolation and Molecular Characterization of Elite Indigenous <i>Rhizobia</i> Nodulating <i>Phaseolus</i> bean (<i>Phaseolus vulgaris</i> L.)

“…It is the nutrient most required for plant growth and is a key for good yield of agriculturally important crops [56]. It is a primary nutrient for plant growth and survival due to the fact that nitrogen is a source of cells proteins, enzymes and chlorophyll [57].…”

“…Isolation of rhizobia strain from nonspecific (promiscuous) legumes gives a wide chance of identifying new effective strain for such legumes. [56]. Since common bean is a most important legume crop in most African countries as earlier mentioned, there is a need of isolating elite rhizobia strains nodulating it in areas where its production is practiced but yield potential has never been realized.…”

“…Legumes including Common bean acquire nitrogen by living symbiotically with rhizobia which are capable of fixing atmospheric nitrogen (N 2 ) in root nodules and supplying it to the plant [56]. Genera Rhizobium, Mesorhizobium, Allorhizobium, Sinorhizobium, Arzorhizobium and Bradyrhizobium which all together form Rhizobia, play a vital role in converting free nitrogen in the soil into ammonia [54].…”