Studies On Inheritance Of Resistance To Procymidone And Pathphysiology Of Botrytis Cinerea

In this paper, different isolates of Botrytis cinerea were the research objects. Thehigh-resistant mutants were obtained by inducing sensitive strains with Procymidone. Thedifference of pathogenicity, the physiological and biochemical mechanisms topathogenicity, the physiological and biochemical mechanisms of host resistance werestudied systematically, and the variation of fungicide resistance of B.cinerea was alsodiscussed. The results were summary as follows:1. Study on fungicide resistance to procymidone of B.cinerea. The results showed that the control effect of procymidone and carbendazim was thebest among the four kinds of fungicide including procymidone, carbendazim, mancozeband dithofencarb. The Ec50 value of procymidone and carbendazim was less than 0.5ug/ml.There were significant differences between the control effects of different fungicides todiverse strains isolated from different hosts. In the whole, the sequences of the number ofcontrol effects were carbendazim > procymidone > dithofencarb > mancozeb. The Ec50 value of two high-resistant mutants CF1-1 and CF1-2 belonged tomulti-resistant strains because the two strains had the high resistant level to procymidoneand carbendazim, respectively the resistant mutants grew prosperously on the medium inwhich contained low content of procymidone. While the mycelial growth rate of resistantmutants was higher than that of sensitive strains. The color of resistant mutants colonybecame darker and more abnormal than that of sensitive. These characteristics weredemonstrated that the resistant mutants were accustomed to the environment with lowcontent of fungicide. The conidia bearing quantities of resistant mutants were less than thatof parents strains, it showed that the reproductive capability of resistant mutants toprocymidone decreased compared to inoculating the leaves of strawberry, thepathogenicity of resistant mutants to procymidone was stronger than that of sensitivestrains, and the lesion area was larger than that of sensitive strains. Maybe the co-evolutioneffect resulted in the characteristic of CF1-1 and CF1-2, these were the two mutants ownedthe high resistant level to procymidone and strong pathogenicity. The results of sub-culturing the resistant mutants showed the resistance level ofresistant mutants did not declined when they grew on the medium in which did not containthe two fungicides. The mycelia growth rate declined with the increase of culturegeneration. Maybe it resulted from culture in vitro with long-term. While there were noany influence on the resistance level to procymidone and carbendazim, but the myceliagrowth rate declined significantly when they grew to the tenth generation. The results ofgrowth frequent on the medium with fungicides showed, the growth frequent of resistantmutants in the fifth generation was high and they grew prosperously. The percentage ofsurvived of resistant mutants to carbendazim in the stage of the seventh generation washigh, but that to procymidone decreased to 50%, the percentage of survival of resistantmutants in the stage of the tenth generations decreased to 25%. These characteristicssuggested that the resistance level decrease or lose to some extent when these resistantmutants sub-cultured for a long time. The resistant inheritance of B.cinerea to procymidone ivwas stable.2. The mechanism of pathogenicity of Botrytis cinerea Different hosts were inoculated by different strains of B.cinerea isolated from differenthosts, and the intensity of pathogenicity was determined. The result showed that differentstrains had obvious diversities pathogenicity in the same plant, and the same strains haddifferent expression in different plants. Making use of the measure of spectrophotometric analysis to study strawberry leaveswere inoculated by several different B.cinerea strains the pathogenicity enzyme activity ofcarboxymethylcellulose(CMC), β-glucosi...