Systematic Identification Of Fusarium Species Associated With Soybean Root Rot In Dunhua And Gongzhuling Areas Of Jilin Province

Soybean root rot is a serious soil-borne fungal disease in soybean production in the world,which leads to the decline of soybean yield and quality to a great extent.Fusarium species are well recognized as the important causal agent of soybean root rot,but the species of Fusarium are different all over the world.In order to identify the species of Fusarium of soybean root rot in Dunhua and Gongzhuling,Jilin province,the pathogenic fungi were isolated and identified in this study,in order to provide scientific basis for the prevention and control of soybean root rot in Jilin province.There are 93 plants with typical soybean root rot disease were collected from Dunhua and Gongzhuling soybean experimental fields in Jilin province for isolation and purification of pathogenic fungi.Nucleic acid sequence consistency analysis of three conservative genes ITS,TEF1-α and RPB2 was carried out,and the species status of suspected Fusarium isolates was identified by morphological observation.Based on the three conserved genes ITS,TEF1-α and RPB2,the phylogenetic relationship between Fusarium isolates was further confirmed by single gene phylogenetic analysis and multi-gene combined phylogenetic analysis,and their pathogenicity was evaluated by in vitro leaf inoculation and Hypocotyl direct inoculation.The results are as follows:1.In this study,122 strains of fungi were isolated from diseased plants in Dunhua and Gongzhuling area of Jilin province,104 strains of Fusarium classified in 4 species were identified,including F.solani(64.42%),F.oxysporum(33.65%),F.verticillioides(0.96%)and F.proliferaum(0.96%).57 out of the 104 strains of Fusarium were isolated from the diseased plants in Gongzhuling,including F.solani(91.23%),F.oxysporum(5.27%),F.verticillioides(1.75%)and F.proliferaum(1.75%).The other 47 strains were isolated from Dunhua,including F.solani(31.91%)and F.oxysporum(68.09%).The dominant pathogens of species of Fusarium of soybean root rot in the two regions of Jilin province were different.F.solani was dominant in Gongzhuling area,while F.oxysporum was dominant in Dunhua area.2.The results of phylogenetic analysis showed that neither nucleic acid sequence analysis of single gene nor phylogenetic analysis of single gene could make the taxonomic identification of Fusarium genus extremely accurate,but the combined phylogenetic analysis of ITS,TEF-1α and RPB2 could make the taxonomic identification of Fusarium genus more rapid and accurate.3.The pathogenicity analysis of Fusarium isolates showed that among the 57 F usarium isolates in Gongzhuling area,the pathogenicity of F.oxysporum was stronge r,that of F.verticillioides and F.proliferaum was the second,and that of F.solani was weak.Among the 47 Fusarium isolates in Dunhua area,the pathogenicity of F.oxysporum was stronger than that of F.solani.