Plant Growth of the Wild Forage Legume Genista monspessulana is Improved by Bradyrhizobium sp. sv. Genistearum in the Acidic Soils of Northern Morocco.

Genista monspessulana is a wild legume of high fodder value in northern Morocco, where it contributes to livestock feeding, particularly during the lean season. The plant fixes nitrogen in symbiosis with soil bacteria known as rhizobia. To identify and characterize its symbiotic partners, we isolated twenty-two bacteria inhabiting the plant nodules and assessed their phenotypic and genetic diversity as well as their symbiotic efficiency. The 16S rRNA sequences analysis proved that 7 isolates were affiliated with the genus Bradyrhizobium, which significantly improve plant growth under nitrogen deficiency. Based on multi-locus sequence analysis using five different housekeeping genes, three representative strains were selected for further analyses. The phylogenetic analysis of the concatenated sequences of the five genes showed that the closest type strain is Bradyrhizobium canariense LMG 2122265T. The strains nodulate also other Genisteae such as Cytisus villosus and Lupinus luteus besides their host plant. The phylogenetic analysis of the symbiotic nodC gene allowed the assignment of the strains to the symbiovar genistearum. The three strains proved to be very efficient in the fixation of N as revealed by their relative and absolute efficiency indexes and may be used as effective individual or mixed inocula, to improve the plant growth in its natural habitat and contribute to soil restoration, and revegetation in Northern Morocco.