Resource Of Symbiotic Nitrogen-Fixation Of Legume In Some Regions Of Shaan Xi Province And Diversity Of Rhizobia In Shenmu Area

In this research, we investigated and collected the rhizobial resource of legume plant growing in Guanzhong plain and Shanbei loess plateau. The biodiversity of 56 rhizobial strains isolated from Shenmu were studied by using numerical taxonomy and some molecular motheds, such as 16S rDNA PCR-RFLP, 23S rDNA PCR-RFLP and 16S rDNA sequencing. The main results of my research were shown as following.930 nodule samples from 59 species of legumes belonging to 28 genera were collected, 720 rhizobial strains were isolated, and 10 species of legumes such as Indigofera bungeana Walp,Astragalus bhotanensis Baker,Astragalus galactites Pall,Thermopsis chinensis Bench,Oxytropis latibracteata Turtz,Oxytropis ochrantha Turcz,Oxytropis hirta Bunge,Hedysarum fruticosum Pall,Pueraria Lobata Ohwi,Caragana leveillei Kom,were not reported according to our investigation of rhizobia resources of leguminous plants in the middle and northern regions of Shaanxi province including 27 cityï¹  county. Through comparing and researching nodule characteristics, We found that nodule characteristics including size, number, shape, color and growth site was not only related to legume species, also greatly related to ecological condition. This investigation will provide the valuable resources of rhizobia for agricultural production and ecological environment construction.153 phenotypic features (sole C or N resource utilization, antibiotic resistance to NaCl ang alkali,heavy metal) of 56 rhizobial strains in shenmu county were analyzed. Most of the test strains were clustered into three groups at the similarity level of 85%. Groupâ… may be a new group of Mesorhizobium because of no reference strains clustered into it. R.loessense was clustered into Groupâ…¡. M. temperatum was clustered into GroupIII. The result of phenotypic features showed that some rhizobial strain can be resistance to much NaCl, alkali,heavy metal.16S r DNA PCR-RFLP and 23S r DNA PCR-RFLP were applied to study the genetic diversity of 56 rhizobial strains. The result of 16S r DNA PCR-RFLP and 23S r DNA PCR-RFLP were in good agreement with that of numerical taxonomy, with a little difference.The combined data of 16S r DNA PCR-RFLP and 23S r DNA PCR-RFLP analysis...