Diversity Analysis And Serological Assay Of Fusarium Oxysporum In Northeastern Of China

Fusarium Wilt of melon is a kind of melon disease caused by Fusarium oxysporum,its popularity and spread have caused different degrees of economic losses to the melon production in china.In this paper,the population structure of Fusarium oxysporum,pathogenicity and the disease resistance of different varieties of melon were studied and analyzed by traditional morphology and method of molecular biology.ELISA was used to detect Fusarium oxysporum,and established detection method.1.Pathogenic ofFusarium oxysporumTest results are as follows:62 strains of pathogenic bacteria were isolated and purified from musk melon collected from LiaoNing Province,JiLin Province,HeiLongjiang province and the Inner Mongolia Region.On the basis of traditional morphological analysis,the genomic DNA of the tested strains was amplified by using the specific primer FOF1/FOR1 of Fusarium oxysporum,44 strains were identified as Fusarium oxysporum.Pathogenicity test results showed that 44 strains of Fusarium oxysporum on Muskmelon have certain infectivity,thedisease index is between 31.7-83.3,pathogenic of them wasstrong.The test results of the resistance of different varieties of melon showed that,there are 2 high susceptible(HS)varieties,12 susceptible(S)varieties,6 moderately(MR)varities,1(R)varities.No one is high resistant among the 21 kinds of melon seeds.2.Diversity analysis of Fusarium oxysporum44 isolates Fusarium oxysporum from melon in various areas of the northeast were analyzd the genetic diversity by SRAP technique to explore the relationship between genetic diversity and geographical origin.The results indicated that 8 pairs which had rich product sand high polymorphism were selected,generated a total of 53 reproducible bands,53 of which were polymorphic,and similarity coefficient was 100%,with an average of 6.63 for each pair of primers.By cluster analysis,the similarity coefficients of 44 strains fusarium oxysporum were ranged from 0.47 to 0.98,rich genetic variation existed among the tested isolates and there was no correlation between SRAP group and the geographic origin.3.Establishment of ELISAdetection method for Fusarium oxysporumThe polyclonal antibody was prepared by the extraction of the mycelium protein of Fusarium oxysporum,the antibody can be used for the detection of Fusarium oxysporum.Determination by indirect ELISE,the polyclonal antibody was specific to the pathogen of Fusarium Wilt,and its titer was 1:25600.At the same time,the concentration of antibody and antigen were optimized,the optimal dilution of antibody was 1:1000;The working concentration of enzyme labeled antibody was also selected as 1:1000,is determined by taking into account the experimental results and the economic factors.The sensitivity of the antibody was determined,when the antigen was diluted to 0.005 μg/ml,P/N>2.1.The location of the disease was in the rhizomein the early stage of Muskmelon Fusarium Wilt,the Fusarium oxysporum of root was detected by ELISA,the disease was positive and the Healthy was negative.Muskmelon Fusarium wilt is a soil borne disease,we detected the Fusarium oxysporum in soil.The results show that the one year and five years soil were positive,the contents of the two kinds of soil were 2.28 μg/ml and 4.43 μg/ml calculated by the standard curve.Sterilized soil was negative.