Agrobacterium leguminum sp. nov., isolated from nodules of Phaseolus vulgaris in Spain

Abstract

Two endophytic strains, coded MOVP5T and MOPV6, were isolated from nodules of Phaseolus vulgaris plants grown on agricultural soil in Southeastern Spain, and were characterized through a polyphasic taxonomy approach. Their 16S rRNA gene sequences showed 99.3 and 99.4 %, 98.9 and 99.6 %, and 99.0 and 98.7% similarity to ‘ A. deltaense ’ YIC 4121T, A. radiobacter LGM 140T, and A. pusense NRCPB10T, respectively. Multilocus sequence analysis based on sequences of recA and atpD genes suggested that these two strains could represent a new Agrobacterium species with less than 96.5 % similarity to their closest relatives. PCR amplification of the telA gene, involved in synthesis of protelomerase, confirmed the affiliation of strains MOPV5T and MOPV6 to the genus Agrobacterium . Whole genome average nucleotide identity and digital DNA–DNA hybridization average values were less than 95.1 and 66.7 %, respectively, with respect to its closest related species. Major fatty acids in strain MOPV5T were C18 : 1 ω7c/C18 : 1 ω6c in summed feature 8, C19 : 0 cyclo ω8c, C16 : 0 and C16 : 0 3-OH. Colonies were small to medium, pearl-white coloured on YMA at 28 °C and growth was observed at 10–42 °C, pH 5.0–10.0 and with 0.0–0.5 % (w/v) NaCl. The DNA G+C content was 59.9 mol%. These two strains differ from all other genomovars of Agrobacterium found so far, including those that have not yet given a Latin name. The combined genotypic, phenotypic and chemotaxonomic data support the classification of strain MOPV5T as representing a novel species of Agrobacterium , for which the name Agrobacterium leguminum sp. nov. is proposed. The type strain is MOPV5T (=CECT 30096T=LMG 31779T).

Unlocking the diversity and plant‐growth promoting potential of the bulk soil bacteria associated with the Saharan tree Vachellia tortilis subsp. raddiana

“…The bacteria belonging to these genera are agronomically relevant for their PGP traits, and biocontrol activity is known for their ability to produce plant growth hormones, which can be beneficial for plant growth (Dutkiewicz et al., 2016; Luziatelli et al., 2020). Pseudarthrobacter species have been found in the rhizosphere of various plant species, Medicago sativa rhizosphere in Hail District, Saudi Arabia (Sulieman et al., 2022); nodules of Phaseolus vulgaris L. (Castellano‐Hinojosa et al., 2021); and the rhizosphere and bulk soil of Sulla spinosissima (Oubohssaine et al., 2022).…”

Probing the potential of salinity-tolerant endophytic bacteria to improve the growth of mungbean [Vigna radiata (L.) Wilczek]

“…In this study, we reported the occurrence of Agrobacterium leguminum, Achromobacter denitrificans , Pseudomonas extremorientalis and Serratia quinivorans in the roots of mungbean for the first time. Recently, Castellano-Hinojosa et al (2021) isolated A. leguminum from the Phaseolus vulgaris nodules and claimed it as a novel species based on the data obtained from colony morphology, sequence analysis, phylogenetic analysis and taxonomic characterization. Previously, Sultana et al (2020) isolated A. denitrificans from the rice plant, which showed PGP properties under salt stress.…”

Complete genome sequencing of Agrobacterium leguminum strain EL101 isolated from Khaya senegalensis tree bark using nanopore technology

“…Agrobacteria are commonly found in soil microflora, with the majority being non-phytopathogenic ( 1 ). Recently, a novel species, Agrobacterium leguminum , was first isolated from the nodules of Phaseolus vulgaris grown in southeastern Spain ( 2 ).…”