Mesorhizobium muleiense sp. nov., nodulating with Cicer arietinum L.

Abstract

Three chickpea rhizobial strains (CCBAU 83963 T , CCBAU 83939 and CCBAU 83908), which were identified previously as representing a distinctive genospecies, were further studied here and compared taxonomically with related species in the genus Mesorhizobium. Results from SDS-PAGE of whole-cell soluble proteins revealed differences from closely related recognized species of the genus Mesorhizobium. ; only Cicer arietinum, its host plant, could be invaded to form effective nitrogen-fixing nodules. The narrow spectrum of utilization of sole carbon sources, lower resistance to antibiotics, and NaCl, pH and temperature growth ranges differentiated these novel rhizobia from recognized species of the genus Mesorhizobium. Based on the data presented, the three novel rhizobial strains are considered to represent a novel species of the genus Mesorhizobium, for which the name Mesorhizobium muleiense sp. nov. is proposed. The type strain is CCBAU 83963 T (5HAMBI 3264 T 5CGMCC T ).Previously, the predominant symbiotic nitrogen-fixing bacteria associated with chickpea (Cicer arietinum L.) in Europe and in India have been classified as members of the genus Mesorhizobium, including Mesorhizobium ciceri, Mesorhizobium mediterraneum, Mesorhizobium amorphae, Mesorhizobium loti and Mesorhizobium tianshanense (Laranjo et al., 2004(Laranjo et al., , 2008L'taief et al., 2007; Maâtallah et al., 2002;Nandwani & Dudeja, 2009;Nour et al., 1994Nour et al., , 1995 Rivas et al., 2007). Similarly, 95 chickpea nodule isolates collected from alkaline soil in Xinjiang, China, in our previous study were identified as representing a novel Mesorhizobium genomic species closely related to Mesorhizobium temperatum, M. mediterraneum and Mesorhizobium robiniae based on genomic analyses, including BOX-PCR, 16S rRNA PCR RFLP, intergenic spacer PCR RFLP, multilocus sequence analysis (MLSA) and DNA-DNA hybridization (DDH) studies (Zhang et al., 2012).To determine the taxonomic status of these chickpea rhizobia, phenotypic characteristics, cross-nodulation tests, fatty acid profiles and other genetic information were further investigated and compared with related species in the current study. Based on the evidence from previous and the current study, these chickpea rhizobia are considered to represent a novel species of the genus Mesorhizobium.In the present study, the bacterial strains were cultured at 28 u C on modified-yeast mannitol agar mediumAbbreviations: DDH, DNA-DNA hybridization; MLSA, multiple locus sequence analysis.The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA, recA, glnII, atpD, nodC and nifH gene sequences of strain CCBAU 83963

Phylogeny of Nodulation Genes and Symbiotic Diversity of Acacia senegal (L.) Willd. and A. seyal (Del.) Mesorhizobium Strains from Different Regions of Senegal

“…Our results are in accordance with previous studies based on a large number of isolates showing that nifH phylogenies are broadly similar to those of nodulation genes [30]. In the particular case of Mesorhizobium spp.…”

Mechanism of Phosphate Solubilization and Physiological Functions of Phosphate-Solubilizing Microorganisms

“…Cohen et al (2009) in a similar study suggested that ABA produced along with gibberellins by PGPR strain significantly contributed to water stress alleviation of maize plants. Some rhizobial strains such as B. japonicum USDA110 also produce ABA (Boiero et al 2007) and function in the same way as do the other PGPR (Zhang et al 2012). …”

Genotypic alteration and competitive nodulation of Mesorhizobium muleiense against exotic chickpea rhizobia in alkaline soils

“…Several other chickpea rhizobia belonging to known species in the genus Mesorhizobium have also been detected in Spain and Portugal [13]. Despite the diversity of Mesorhizobium species nodulating chickpea, the highly conserved symbiotic genes nodC and nifH are shared across these species [9,13,23,24]. Most recently, Armas-Capote et al reported that more than nine Mesorhizobium genospecies could nodulate Cicer canariense in a natural habitat on La Palma, Canary Islands [2].…”

“…Chickpea nodulation and rhizobial inoculation have been studied intensively in many countries during the last three decades [2,[14][15][16]. Three main rhizobial species specifically nodulating chickpea have been described: Mesorhizobium ciceri and Mesorhizobium mediterraneum in Spain [1,11,12], and Mesorhizobium muleiense in Xinjiang, China [23]. Several other chickpea rhizobia belonging to known species in the genus Mesorhizobium have also been detected in Spain and Portugal [13].…”