First report of Rhizobium pusense within Voandzou (Vigna subterranea (L.) Verdc.) rhizosphere in Côte d’Ivoire

There is currently no information on the diversity of indigenous rhizobial populations associated with bambara groundnuts (Vigna subterranea L. Verdc.) in Côte d’Ivoire soils. The aim of this study was to assess the diversity of microsymbionts nodulating a Bambara groundnut landrace in north of Cote d'Ivoire. For this purpose, a local bambara groundnut accession was used to trap root nodules bacteria from three soils obtained from farmers’ fields in North Côte d'Ivoire. It was shown that all the isolates had very fast growth rates on YEMA and not absorbing Congo red. All isolates were gram negative rods and able to grow in a TY medium at pH ranging from 5.8 to 8.8 and at temperatures up to 45°C. The 16S RNA gene phylogeny showed three main clades including Rhizobium sp., an unclassified species and R. pusense. 16S RNA gene identification of the strain K39 as R. pusense was congruently confirmed by atpD gene phylogeny. Strain K39 did not nodulate bambara groundnut plants. This is the first report of the presence of R. pusense in Vigna subterranea (L.) Verdc.) rhizosphere in Côte d’Ivoire.