| Sclerotinia sclerotiorum (Lib.) De Bary is host widely and non-specific plant pathogenic fungi, and it is also the rape of china and other various economic crops’ important plant pathogenic bacteria. The research of S.sclerotiorum mainly focus on the identification and selection of resistant varieties, disease resistance mechanism, resistance gene cloning and genetic diversity, etc, at home and abroad. At present the related research reports have not been seen whether the variation of host varieites has influence on the same sclerotinia isolates of pathogenic differentiation and genetic differentiation. The research was mainly the research that vaccinating the same bacterial strains of S.sclerotiorum to the internal of stems of various of rapeseeds, and again from stem collected in the sclerotia, and then after separation and purification of bacterial strains of S.sclerotiorum to study the morphology, pathogenic differentiation and genetic differentiation, so as to get whether there is difference between biological characteristics, pathogenic differentiation, genetic differentiation the same bacteria strains of S.sclerotiorum and the primary causes of the pathogenic differentiation and genetic differentiation, test results are as follows:1、Isolated89strains of S.sclerotiorum, collected from the inoculation the same S.sclerotiorum stem of different rapeseed varieties. Through the determination of the growth speed of hypha of bacteria strains and morphological characteristics, it showed that there were significant differences of the different strains in the colony morphology, growth speed of hypha, matrix color, the number. After training various strains in the PDA, the cultivatable matrix can be divided into four differences, white, light brown, green, and livid brown;89bacteria strains basically could be divided into12colonies form; the growth speed of Hypha’ range were0.53cm/d-2.68cm/d; Their fresh weight and dry weight of the range were0.00g～1.23g and0.00g～0.59g. Analysing the relationship of the morphological properties in the growth speed of89bacteria strains of S.sclerotiorum and hypha, their weight (dry weight and fresh weight) and their number, etc, the results showed that the indexes of different morphology characteristics are markedly different. Through the analysis of the characteristics of biology,46bacteria strains of S.sclerotiorum were screened as the selected material for the late experiment.2、Accounding to the pathogenicity assay on the46plants of S.sclerotiorum strain adopted by leaves in vitro and stem in stem inoculation method, the results indicated that there is obvious difference in pathogenicity of every strain to the rape. Inoculation every strain by leaves in vitro method after96h, the length of the scab is around0cm～5.78cm, however, adopt the leave in stem method after15h, the length is around0cm～4.8cm. The result prove that even the same S.sclerotiorum strain inoculation different rape cultivars, the acquired S.sclerotiorum strain exist virulence difference. Inoculation every strain by leaves in vitro method after96h, the length of the scab is around0cm～5.78cm; however, adopt the leave in stem method after15h, the length is around0cm～4.8cm. The result prove that even the same S.sclerotiorum strain inoculation different rape cultivars, the acquired S.sclerotiorum strain exist virulence difference. According to the result of rape friend resistance at sichuan academy of agricultural science institute of plant protection in2010, the46cultivars can be divided4resistant group:resistance, slightly susceptible, moderate susceptible, highly susceptible. Meanwhile, statistical analysis on the4types, the result prove that the disease spots’ length of the S.sclerotiorum strain analysis by the leaves in vitro method is same to the leaves in stem.The virulence difference is obviously in different group of strain. And after the multiple comparison, the result is in the rape cultivars in2010, the pianissimo Possibile virulence of sclerotinia sclerotiorum strain is the "group of resistance ", the group of moderate susceptible is forte fortissimo. The order is moderate susceptible> moderate susceptible> Slightly susceptible> resistance. Thus it can be seen that there is connection between the S.sclerotiorum strain’s differentiation of virulence and the rape cultivars resistance.3、46rapeseed varieties were inoculated with a same strain of S.sclerotiorum by stalk toothpick inoculation method, then collected and isolated the sclerotias from stalks. SRAP markers was used to analysis the genetic differentiation of46isolates of S.sclerotiorum. A total of357scorable fragments were identified with twelve SRAP primer combinations; among them273were polymorphic loci (76.47%). UPMGA (Unweighted Pair Group Method with Arithmetic Mean) indicated that the dendrogram consisted of seven groups, when the genetic similarity coefficient was0.77. AMOVA (Analysis of Molecular Variance) revealed that the percentage of variation among populations differed by host resistant level(98.5%, P<0.001), by cultivar type (105.16%, P<0.001), and by breeding ground (95.36%, P<0.001), but variation among populations of different breeding ground plants was extremely significant (4.64%, P<0.001). And on the basis of POPGENE analysis about46isolates of S.sclerotiorum which are grouped according to breeding ground of the host breeding strains show that genetic differentiation coefficient is0.048and Gene flow is10.031. The result with AMOVA analysis results are basically the same. One of the most significant results in this study was that S. sclerotiorum isolated from different varieties of oilseed rape inoculated with the same strain are genetic differentiate between strains, and that genetic differentiation was closely related to rapeseed breeding ground. |
PDF Full Text Request