Symbiotic Matching Between Soybean Rhizobium And Soybean Cultivars

In this study, the method of nutritious liquid culture was selected to determine the symbiotic matching combinations between sinorhizobium fredii, Bradyrhizobium japonicum and soybean cultivars representing soybean core germplasm varieties in China, and the significant differences of symbiotic matching abilities between Bradyrhizobium japonicum USDA110-A and 2178 with soybean cultivar Suinong20 was primarily analyzed by proteomic technique to research for the reasons of diversity in symbiotic matching abilities between USDA110-A and 2178. This work will provide some useful information for the selection of rhizobium strains in agricultural production and materials in the investigation of soybean breeding, and through this work the symbiotic system with excellent symbiotic abilities and superior nitrogen fixation activities would be got.The crossed nodulation test between 18 soybean rhizobium and 11 soybean cultivars shows that: (1) different soybean rhizobium strains have a great diversity in nodulation and nitrogen fixation; (2) S. fredii exhibit more critical than B. japonicum in nodulation; (3) USDA110, 113-2, HH103 are superior broad-hosted in symbiotic nodulation; (4) Beijingheidou, Shang951099, Zheng92116 have excellent symbiotic matching abilities with soybean rhizobium. Among the matching combinations, USDA110-A could nodulate well with Suinong20 while 2178 could not. These 2 combinations were perfect materials in the study of symbiotic nodulation mechanism between rhizobium and their host pants.The protein expression profiles of USDA110-A, 2178 were analyzed after they were disposed to daidzein of Suinong20. The results showed that: USDA110-A had 8 up-regulated proteins and 7 down-regulated proteins in expression with significant difference, while 2178 had 5 up-regulated and 7 down-regulated proteins. Differentially displayed proteins from USDA110-A and 2178 were analyzed by MALDI-TOF-MS, and 20 of them were identified, except protein 12 from USDA110-A and proteins 1, 3, 5, 11, 18 from strain 2178. Of the 20 proteins, 14 proteins'functions have been reported while the other 6 are not.Among the identified proteins up-regulated from USDA110-A in this study, PHDPS synthase, metal-dependent phosphohydrolase, glycosyl transferase family 2 executed functions related with nodulation and they were involved in synthesis of EPS which has a close relation with symbiotic nodulation. ABC-type organic solvent transporter was a transmembrane protein. It could change the structures of the nodule factors by enhancing the secretion of the nodule factors from inner of the rhizobium cells, which heightened the appetency of rhizobium with their host plants. But neither the proteins related to synthesis of EPS nor proteins related to symbiotic nodulation was detected in strain 2178. The differences of rhizobium in responses to daidzein was one of the most important reasons that cause varieties in symbiotic matching ability.