Analysis Of Chestnut Blightin Pathogenic Difference

In order to investigate the pathogenic difference of chestnut blight fungus, we measuredthe pathogenicity of many strains collected from distinct locations, such as Beijing, Shandong,Hubei and so on.We acquired23strains of endophytic fungi by separating and purifying the seriouslyinfected branches of chestnut in Zhenan, ShaanXi.1Cryphonectria parasitica (Murr) marr.To reveal the pathogenicity of46pathogenic strains who are from Bingjing、Hubei, they wereinoculated to healthy branches as a oval plaque formation. Comparing the plaque on thelongitudinal, transverse and area, we found that pathogenic bacteria collected from differentplace harbor various pathogenicity, and strains collected from BeiJing Huairou confer thegreatest risk. Then Meishan, Ya ’an, Sichuan, Shandong Taian, Beijing Miyun, Sichuan Gulin,Shimian, Beijing Changqing, in turn, drops, pathogenic capacity is slightly lower than BeijingHuairou; And Chongqing Tongliang, Fengdu, Kaixian, Jiangjin, Zhongxian, Hubei Wuhan,Yichang pathogenic ability is lower than the former, the Shaanxi Zhenan, Ningshan,Shangnan irulence is weakest.To analyse the virulence of46strains pathogenic bacteria, we observed the color colony,found that different strains present distinct color. The colony from the Shaanxi Zhenan,Ningshan, Shangnan regions appeared light color-almost white, and would not change withgrowth. These are assigned to the weak virulence, level Ⅰ.The other is of stronger virulence.Strains collected from Beijing Huairou, Miyun are of orange, and the color would be deeperwith its growth, they belong to level Ⅲ. The rest showed great various. Some colonies’centers are white, and edge appear light yellow, the toxicity can be stronger than the onewhich center is light yellow and edge is white. Overall, level of virulence strains of these twois between the first and two classes, which means level Ⅱ.It will produce laccase inductively by doing experiment of fermentation with46strainsof pathomycete. Firstly, optimized the fermentation medium preliminary to find out the mostsuitable enzyme production medium and incubation time. It showed that the5thmedium is themost appropriate one and the most suitable enzyme production time is8thdays. In thecircumstances, produced laccase inductively by doing experiment of fermentation with46 strains of pathomycete, extracted crude laccase enzyme, measure the absorbance value under420nm ultraviolet light waves. The results showed that the ability of secreting laccase aredifferent from different regions where the pathomycete fermented from. The value ofenzymatic activity is the highest in Beijing Huairou. The value in Sichuan Meishan, ShandongTaian, Beijing Miyun, Changping is followed after Huairou.Then the value in Gulin, Shimain,Sichuan, Chongqing and Sichuan Tongliang, Fengdu, Kaixian, Jiangjin, Zhongxian aredeclined gradually. The value in Hubei Wuhan, Yichang, Shaanxi Zhenan, Ningshan andShangna is to a minimum.Doing a confrontation training experiment combied46strains from Beijing, Hubei andShaanXi. Studyingits the vegetative compatibility group by training on PDA plate confrontlywith maching these strains with each other. The results showed that the vegetationcompatibility among those strains can be divided into2types: the compatibility and theincompatibility. The hyphae will fused with each other among the compatibility under themicroscope. And the confrontation between the strains area is not obvious. Theincompatibility strains have3types: type Ⅰ iscompatibility strong, which the fighting areaswill be appeared on both sides of conidium belt. TypeⅡ is weak incompatibility. The hyphaeill fused hardly with each other among the weak incompatibility, which have no producingconidium belt in the against areas,who is made up with hyphae; Type Ⅲismiddle-incompatibility, which is between Ⅰ and Ⅱ. They have the fighting areas obviously,which conidium belt producd in the against areas lonely, the hyphae producd on the other sidelonely.