Genetic and symbiotic characterization of rhizobia isolated from tree and herbaceous legumes grown in soils from ecologically diverse sites in Kenya

摘要: Abstract Natural genetic diversity and symbiotic status were studied among 41 root nodule bacteria from ecologically diverse sites in Kenya having no history of growing domesticated legumes, but where species Acacia Sesbania sesban grow naturally. Isolates originated either nodules field plants (trees shrubs) or trap host grown field-collected soil. The mellifera , nilotica nubica polyacantha seyal tortilis xanthophloea Faidherbia (Syn. ) albida Prosopis juliflora S. Macroptilium atropurpureum Phaseolus vulgaris Vigna unguiculata . Two molecular methods used to characterize these strains; PCR–RFLP the 16S rRNA gene (12 distinct genotypes) sequence analysis a 230 bp fragment this (10 with former showing better discriminatory power. two good agreement delineating five bacterial genera: Agrobacterium Bradyrhizobium Mesorhizobium Rhizobium Sinorhizobium strains all alkali-producing, exhibiting very slow intermediate growth; acid-producing fast growth, showed growth. further revealed corresponding elkanii japonicum leguminosarum tropici IIB, as well others characterized genus level only. Apparent varied site was greatly influenced by isolation. For example, rhizobial genotypes (four genera) found using different single woodland site, thus reaffirming occurrence heterogeneous population regardless their nodulating ability native legume species. spp. ( F. ), known for preference tropical African soils, abundant widespread mainly because most frequently host. Twenty Kenyan eight reference tested on tree that are priority use; considerable characters. Whereas variation effectiveness test strains, nodulated effectively only its homologous strains. -allied failed nodulate any tested. high (rhizobial genotypes, affinities effectiveness) will require rigorous selection host×strain×site combinations order obtain effective competitive inoculants trees crops rehabilitation agroforestry programmes.