Genetic Analysis And Mapping Of Resistance Genes Against Bean Common Mosaic Virus In Soybean V94-5152

Glycine max is one of the most important economic crops in the world whose growth is threatened by many pathogens,among which the soybean mosaic disease caused by virus is very widespread and often seriously ruduces soybean yield and quality.For a long time,researchers took Soybean mosaic virus?SMV?as the main pathogen of soybean mosaic disease and carried out a great number of studies.At present,at least four SMV resistance loci?Rsv1,Rsv3,Rsv4 and Rscl5?have been found.However,recent researches showed that Bean common mosaic virus?BCMV?,a SMV closely related species,also can effectively infect soybean in different parts of our country,which constitutes serious threat to soybean yield and quality,while there have been few reports of soybean resistance to BCMV.Therefore,to investigate the inheritance of BCMV resistance gene in soybean and fine mapping its region have important value of science and application for further utilizing this gene locus to cultivate and plant resistant soybean varieties.In this study,BCMV resistance variety V94-5152 and BCMV susceptible variety Williams 82 were used to construct a hybrid genetic population.We used BCMV strain HZZB011 to infect 292 F2 individuals and recorded their phenotypes,these data supported that the resistance in V94-5152 against BCMV-HZZB011 was controlled by a single dominant gene?3R:1S,P>0.05?.By screening 845 SSR?Simple sequence repeat?markers distributed on soybean different chromosomes,we obtained 211 SSR markers showing polymorphism between two parents.Bulked Segregant Analysis?BSA?and the verification experiments of using 20 susceptible individuals found that the BCMV resistance gene was closely linked with 9 SSR markers on chromosome 2.Next,a genetic linkage map based on the genotypes of all 292 F2 individuals in 9 S SR markers and their phenotypes found that the BCMV resistance gene should locate between SSR markers BARCSOYSSR₀2₀611 and BARCSOYSSR₀2₀617,the genetic distance to two markers are 0.1 cM and 0.3 cM respectively.In order to confirm this mapping result,we further selected 28 F2:3 lines based on their recombinant types and inoculated them with HZZB011 for observing phenotypes,the data of cross-over points and F2.3 phenotypes supported that the BCMV resistance gene was located between BARCSOYSSR₀2₀611 and BARCSOYSSR₀2₀617,it was consistent with the genetic linkage map.According to Williams 82 reference genome,we found there are five genes in such region.By using specific primers to amplify them in V94-5152,we initially obtained the sequences of three genes,they are Glyma.02G121300,Glyma.02G121400 and Glyma.02G121500 respectively.Sequence alignment showed that there is no difference between resistant and susceptible cultivar neither Glyma.02G121300 nor Glyma.02G121500,while Glyma.02G121400 has three SNPs between resistant and susceptible cultivar,and only one of them is nonsynonymous mutation.Since the sequences of Glyma.02G121600 and Glyma.02G121700 were not amplified,the explicit candidate gene are still to be revealed by further experiments.Finally we need specially point out that the mapping result of the BCMV resistance gene in soybean varieties V94-5152 was almost in the same interval with previously reported SMV resistance locus Rsv4,which means that V94-5152 could use the same genes to response the threat of SMV and BCMV at the same time,reflecting that this locus has important research and application value.