The Pathogenicity Differentiation And Cross-pathogenicity Of Verticillium Dahliae On Cottons And Eggplants

The Verticillium dahliae could infect more than 600 plants and cause Verticillium wilt disease,including cotton,eggplant,pepper,sunflower and potato.Cotton and eggplant verticillium wilt are serious and cause great economic losses in China.On account of V.dahliae widely distribute range,diversity host and strong variability,the pathogenicity is well differentiation.There is no effective resistant varieties in agricultural production.The isolates of highly virulent defoliating(D)pathotype of V.dahliae had been identified in Henan Province.But the distribution and pathogenicity differentiation of defoliation strains in Henan are not clear.There are less research on the pathogenicity differentiation on eggplant V.dahliae.It is still unknown about the cross-pathogenicity of V.dahliae from different hosts.1.In this study,the plants of cottons and eggplants with the symptoms of Verticillium wilt disease were collected from different regions in Henan province.38 isolates from cottons and 65 isolates from eggplants were obtained and all of the isolates are V.dahliae by the morphological characteristics of the pathogen and the molecular biology identification.2.The mating type genes of V.dahliae isolates were identified using the specific primers Alf3/MAT11 R and HMG21F/MAT21 R.All the V.dahliae isolates fron cottons and eggplants existed with the mating type gene MAT1-2-1,but without the mating type gene MAT1-1-1.The physiological race of V.dahliae isolates were also identified using the specific primers Vd Ave1F/Vd Ave1 R and Vd R2F/Vd R2 R.All of the isolates in this study are race 2 except the strain Vdq6 from eggplant,which is race1.V.dahliae isolates infecting cotton and eggplant could be classified into defoliating(D)or nondefoliating(ND)pathotypes based on the PCR amplification using the specific primers INTD2F/INTD2 R and INTND2F/INTND2 R.There were 38 isolates of the D pathotype from cottons,accounting for 94.7%,and 2 V.dahliae cottons isolates are nondefoliating(ND)pathotype,accounting for 5.3%.This results indicated that the V.dahliae isolates of the D pathotype from cottons were the dominant population.While 27 isolates from eggplants belonged to D pathotype,accounting for 41.5%,and there were 38 isolates of the ND pathotype from eggplants,accounting for 58.5%.3.The pathogenicity 36 isolates from cottons of D pathotype were tested on cotton resistant cultivar Zhongmiansuo 41 and susceptible cultivar Jimian11 through dipping root inoculation.It is highly significant difference between the defoliation V.dahliae from cottons in Henan.The strong virulent strains are 30,reach 83.33%.The medium virulent is 6,reach 16.67%.The strong virulent defoliation V.dahliae have been the major members in Henan cotton regions.The isolates from cottons were classified into 3 types,which are AVH,AVM and AVS.There is no significant difference between the different colonial morphology and pathogenicity.There is no correlation between geographic origin or growth rate and pathogenicity of defoliation V.dahliae from cottons in Henan.4.The pathogenicity 65 isolates from eggplants were tested on eggplant resistant cultivar Tuolubamu and susceptible cultivar Heishuai 1 hao through dipping root inoculation.It is highly significant difference between the V.dahliae from eggplants in Henan.The strong virulent strains are 52,reach 80%.The medium virulent is 12,reach 18.5%.The weak virulent is 1,reach 1.5%.The strong virulent V.dahliae has been the major members in Henan cotton regions.The V.dahliae from eggplants are divided into D pathotype and ND pathotype strains,and it is not significant difference between the pathogenicity of D pathotype and ND pathotype strains.The isolates from eggplants were classified into 3 types,which are AVH,AVM and AVS.There is no significant difference between the different colonial morphology and pathogenicity.There is no correlation between geographic origin or growth rate and pathogenicity of defoliation V.dahliae from eggplants in Henan.5.Inoculated 10 isolates from eggplants to cotton resistant cultivar Zhongmiansuo41 and susceptible cultivar Jimian11.The average disease index of isolates from eggplants on Zhongmiansuo41 and Jimian11 is 24.77 and 41.35.Comprehensive view,the pathogenicity of V.dahliae from eggplants is weaker than V.dahliae from cottons on resistant cultivar Zhongmiansuo41 and susceptible cultivar Jimian11.6.Inoculated 10 defoliation isolates from cottons to eggplant resistant cultivar Tuolubamu and susceptible cultivar Heishuai 1 hao.The average disease index of isolates from cottons on Tuolubamu and Heishuai1 hao is 36.04 and 43.96.Comprehensive view,there is no differences between the pathogenicity of V.dahliae from cottons and V.dahliae from cottons on resistant cultivar Zhongmiansuo41 and susceptible cultivar Jimian11.