| Soybean is one of the most important economic crops in the world,and it is also the main source of plant protein and edible oil.Rhizobium and leguminous plants have formed a unique system of symbiotic nitrogen fixation through long-term evolution,and their nitrogen fixation amount to nitrogen fixation and nitrogen fixation is very large.China is the birthplace of soybean and Rhizobium isolated,with regional characteristics of the local resources of soybean rhizobia and inoculation screening nodulation ability strong from the soil,it can not only alleviate the dependence on agricultural industrial nitrogen and provide theoretical support for the research of Rhizobium symbiotic nitrogen fixation system with soybean.This experiment using the Rhizobium HD001 lab has separation of nodulation ability identification of 141 soybean germplasm resources of materials,at the same time in 5 different regions of the country from soil samples,separation and purification of 14 to capture the host for rhizobia by Suinong,has the characteristics of colony morphology of rhizobia strains.It was confirmed by phenotypic verification and molecular verification that the isolated strains were slow growing rhizobia,and can be used as a candidate for further field trials.The results are as follows:1.The nodulation ability of 141 soybean resources was identified and the nodulation index of 141 soybean germplasm resources was obtained.The difference of nodulation was obvious,and the number of nodules was 0-37.The nodulation ability of different soybean germplasm resources can be used as the basis for deep study on the ability of soybean nodulation.2.The Rhizobium was isolated from the soil of 5 regions of China from the host of Suinong 14,a major soybean variety in Heilongjiang province.110 strains were isolated and purified from the dilution line method of yeast juice mannitol(YMA)Congo red solid medium.The isolated strains were found to be Gram-negative bacteria by Gram staining,and 8 of them were Gram-negative bacteria.Of these strains were cultured were detected,8 strains in yeast extract mannitol(YMA)Congo red solid medium after 5 days,monoclonal colony,colony morphology of transparent or translucent,white or milky white,low convex,smooth edge,oval,straight sizes.The 16 S rDNA gene sequence analysis results show that the 16 S sequence of rDNA gene and NCBI gene amplification strains on the known sequence of the 5 strains,determine the conserved sequence of 16 S rDNA and Bradyrhizobium(Bradyrhizobium japonicum)similarity is 98%,to sum up,the 5 strains were slow growing Rhizobium(Bradyrhizobium japonicum).The nodulation characteristics of Rhizobium in different soybean germplasm resources were obtained after the isolated Rhizobium 48 was further returned to some germplasm resources,which could be used as a candidate for further field production test. |
