Prof.  Dawei  Xin
Northeast Agricultural University,  China

Title: Screening and identification of soybean rhizobacteria and its application in production

Abstract:

In response to the problem of over-application of nitrogen fertilizer for years during soybean cultivation in Heilongjiang Province. With the main loaded cultivar Suinong 14 as the capture host in Heilongjiang Province, and the soil of legume planting all over the country as the capture source, we carried out the isolation and identification of excellent rhizobacteria. More than 200 rhizobacteria, belonging to Bradyrhizobium sp. and Sinorhizobium sp. were obtained through isolation and identification. The physicochemical properties of rhizobacteria were further screened and identified, and excellent rhizobacteria with acid, alkali and seed coating agent resistance were obtained. The colonization characteristics of the superior rhizobacteria and control rhizobacteria on soybean were verified using the split-root assay. The rhizobia with acid, alkali and seed-coatant resistance colonized soybean significantly better than the control rhizobia. Field back-colonization of soybean rhizobacteria for nitrogen fertilizer substitution test revealed that the isolated and obtained rhizobacteria could significantly enhance the yield of soybean. In order to excavate the key genes regulating the interactions with rhizobia in soybean and guide the genetic improvement of symbiotic nitrogen fixation traits in soybean. The genome of Rhizobium was further sequenced and annotated. The type III secretion system was found to be significantly different in different soybean rhizobia. In order to identify the genes in soybean that have a reciprocal relationship with the type III effect in Rhizobium, a combination of genetic targeting and transcriptome was used to identify soybean genes that have a reciprocal relationship with the type III effector NopT in Rhizobium. By constructing CRISPR knockout and overexpression plants of the soybean genes, it was further determined that GmPBS1 could affect nodulation-related traits such as the number of raw nodules and the efficiency of symbiotic nitrogen fixation in soybeans by interacting with NopT. The results of this study are of great theoretical significance and application value in guiding the genetic improvement of symbiotic nitrogen fixation traits in soybean and the popularization and application of soybean rhizobacteria.

Biography: