| In the whole growth period,cotton(Gossypium Spp.)is threatened by Verticillium dahliae.There is few upland cotton varietie germplasm to immune and highly resistant Verticillium wilt,and the progress of breeding cultivaris resistance to the disease is very slow.Different cotton varieties have different resistance levels to Verticillium wilt,but the mechanism of the different resistance is not clear.To reveal the relationship between resistance to Verticillium wilt of cotton and defense reaction level,and the dissemination way of Verticillium dahliae,the objective used the Verticillium dahliae which marked by green fluorescent protein(GFP),study on the differences of defense responses when different resistance cotton varieties was infected by Verticillium dahliae,and pathogenic effect of Verticillium wilt which transmit through the air.The main contents and results of this study were as follows:1.The relationship between upland cotton Verticillium wilt resistance level and immune responseAfter six different varieties of upland cotton were inoculated with Verticillium dahliae spore suspension,the resistances of cultivars were evaluated.The Verticillium dahliae biomass in cotton roots,hypocotyl and lea,ves were negatively related with resistance level,and lignin content of hypocotyl and leaves callose increased with the enhancement of disease resistance,the activity phenylalanine ammonia lyase(PAL),polyphenol oxidase(PPO),peroxidase(POD)and catalase(CAT)were positively related with disease resistance.These results showed that the immune response was related to the resistance enhancement after Verticillium dahliae infection.2.Verticillium dahliae infecting cotton plants in different parts of different defense response excitationThe seedlings of upland cotton cultivar Sumian 9 were inoculated with Verticillium dahliae by the irrigation root inoculation method and leaf inoculation method to study the defense response after inoculation.After seedlings of upland cotton were inoculated with Verticillium dahliae,the callose deposition,hydrogen peroxide accumulation,defense gene expression and the increase of defensive enzymes activity were detected,and the changes of defense reaction characteristics of the irrigation root inoculation method was more than the leaf inoculation.3.Cloning of Verticillium dahliae flagellin gene and elongation factor geneVerticillium dahliae flagellin gene(Flag)and elongation factor gene(Tu)were found from NCBI gene library,and PCR primer were design,two genes were cloned from three different pathogenic strains of Verticillium dahliae Vd07038,V1070,Bp2.The two genes of Verticillium dahliae may be the new type of flagellin and elongation factor gene family;flagellin and elongation factor have the relationship with Verticillium dahliae induced immune response in seedling of Sumian 9 which were inoculated three strains by root irrigation method.The expression of flagellin and extension factor gene in Sumian 9 and Lumianyan 21 inoculated with V1070 were detected.There was no relationship between the pathogenicity and the Flag and Tu expression;the expression of Flag and Tu of Lumianyan 21 seedlings which were inoculated with V1070 appeared surge and a sharp decline,but this phenomenon was not discovered in Sumian 9.4.The Verticillium dahliae can tansmit through the airThe seeds of Sumian 9 were planted in plastic pots and inoculated with Verticillium dahliae V1070-2 which marked by green fluorescent protein,there was Verticillium dahliae colonization on the plants which was not inoculated with V1070-2 and was sequestered with the inoculated plants.With the increase of distance with the plants which were inoculated with V1070-2,the Verticillium dahliae infection time of the plants which was not inoculated with V1070-2 was delay and the total of Verticillium dahliae was decreased.The result indicated that the Verticillium dahliae could spread through the air.In this study,there were new ideas on the interaction mechanism between cotton and Verticillium dahliae. |
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