Biodiversity of Root-Nodule Bacteria Associated With the Leguminous Plant Biserrula pelecinus

Abstract

Biserrula pelecinus is a noteworthy forage legume known for its drought- and acid-resistant properties and nitrogen-fixing ability that forms an extremely specific symbiotic relationship with bacteria from genera Mesorhizobium. To investigate the biodiversity of root- nodule bacteria associated with B. pelecinus, a total of 88 bacterial strains were examined using repYpolymerase chain reaction amplifica- tion. The 16S rRNA gene sequencing was also used to determine the phylogenetic relationship with type strains of different genera of rhi- zobia. Our results show that although a considerable genetic variability among Biserrula isolates was found, most isolates were phylogenetically related to Mesorhizobium ciceri. Curiously, a new symbiotic partner was found to nodulate Biserrula, suggesting possible lateral gene transfer of nodulation and nitrogen fixation genes between Mesorhizobium and Rhizobium.