| Rhizobia, isolated from broadbean in 24 different regions of 11 provinces of China were analyzed by numerical taxonomy, BOX-PCR, 16S rDNA PCR-RFLP and IGS PCR-RFLP, 16S rDNA full length sequencing and cross-nodulation experiments.The analysis of BOX-PCR divided the 73 strains into 18 groups and 5 unattached branch at the similarity of 70%; Based on the result of BOX-PCR, fifty strains with 11 refernence strains were tested by numerical analysis of 138 physiological and biochemical characters. The result showed that the 50 strains were divided into 4 distinctive clusters at the similarity of 81 % with another 8 unattached branch; Furthermore 25 strains as the representation of the broadbean rhizobia with 11 reference strains were selected to PCR-RFLP of 16S rDNA analysis.The 25 strains were clustered into 4 groups at the similarity of 85% with another 1 unattached embranchment. This result was in good agreement with that of numerical taxonomy, The characterization of 35 strains including 11 reference strains were performed by 16S-23S rRNA intergenic gene spacer(IGS) RFLP. Compared with 16S rDNA PCR-RFLP, the result of IGS RFLP showed more differences among strains.The full length of 16S rDNA of the center strains: XZ-SX01-6, SC-HY1 , SX-YX11 and another two representative strains: SC-YA3, SX-YX15 were sequenced and analyzed with the fifteen reference strains. The results displayed that all the representative strains belonged to the same phylogenetic branch of Rhizobium.Ninteen strains of broadbean rhizobia were compared for their growth or survival abilities under the stresses of NaCl, acid, alkali, high temperature and low temperature. The results showed that there were some stains with superior tolerance to NaCl, acid and alkali, while their endurance abilities differred greatly.The strain XZ-SX01-6 was chosen to perform cross-nodulation experiments with 6 legume plants. The results showed that the rhizobium from the broadbean can only nodulate with broadbean and pea. |
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