Deciphering the phylogenetic affiliation of rhizobial strains recommended as chickpea inoculants in Argentina

Abstract

Chickpea (Cicer arietinum L.) is globally cultivated due to its high nutritional value. As with other legumes, itssuccess depends greatly on its inoculation with effective symbiotic rhizobial strains. Since its agriculturalimportance as an alternative winter crop in Argentina is very recent, there are limited phylogenetic studies on the affiliation and origin of the two strains used for its inoculation here. We attempted to define their specific identity through a multilocus sequence approach on seven housekeeping genes (phylogeny and average nucleotide identity), as well as on the basis of 16S rRNA gene sequence and nodC gene analysis. The strains were accurately and conclusively corroborated as M. ciceri and M. mediterraneum species, and their denominations were found to be associated to originally described chickpea-nodulating strains.