酶法制备壳寡糖对番茄灰霉病病菌抑制机理初探

目的：研究酶降解法制备的壳寡糖对番茄灰霉病病菌的抑制机理。方法：测定壳寡糖对番茄灰霉病菌菌丝发育、孢子萌发的抑制作用以及对菌丝形态、细胞膜透性和对菌丝体可溶性蛋白质含量的影响。结果：当壳寡糖处理浓度为1.5mg/mL以上时,对菌丝生长的抑制率达70%以上,EC50为0.72mg/mL。当处理浓度为6mg/mL时,对分生孢子的抑制率显著优于其他浓度水平,达87.4%,EC50为1.48mg/mL。显微观察,浓度为0.8mg/mL的壳寡糖处理可诱导菌丝分枝增多、菌体分隔增加,分生孢子形成受到抑制。此外壳寡糖能够引起菌丝细胞膜透性发生变化,造成菌丝体内含物的渗漏。壳寡糖处理66 h后,菌丝体可溶性蛋白含量比对照降低了36.7%。结论：壳寡糖对番茄灰霉病病菌抑制机理的探究为研究壳寡糖这一新型生物农药的作用机制提供依据。

Primary Study on the Inhibition Mechanism against Botrytis cinerea Pers. of Chitosan-oligosaccharides Obtained by Enzymatic Hydrolysis

Objective: In order to study the inhibition mechanism of the chitosan-oligosaccharides prepared through enzymatic hydrolysis by chi-tosanase to Botrytis cinerea Pers. Method: The inhibition effects of the chitosan-oligosaccharides upon the hyphae and the spore germination of Botrytis cinerea Pers. were studied. And the morphology shape of hyphae, the cell membrane permeability of the pathogen and the content of soluble protein from Botrytis cinerea. treated with the chitosan-oligosaccharides were also investigated. Result: When the concentration of the chitosan-oligosaccharides was over 1.5mg/mL, the inhibition rate to the hypha growth of Botrytis cinerea Pers reached to over 70%, and the EC_(50) was 0.72mg/mL. When the concentration was 6mg/mL, the inhibition rate to the spore germination was more significant than the others, reached to 87.4% . The EC_(50) was 1.48mg/mL. According to the microscope observations, the chitosan-oligosaccharides with concentration of 8mg/mL induced morphological changes, including excessive branching and hyphal segments in the new hyphal of Botrytis cinerea Pers. The formation of conidiospore was inliibited. The chitosan-oligosaccharides could result in the leakage of inclusion of mycelium and in the change of permeability of the cell membrane so as to increase the conductivity. In addition, the inclusion of protein from the pathogen of B. cinerea declined 36.7 % under the treatment of the chitosan-oligosaccharides for 66 hours. Conclusion: The research of chitosan-oligosaccharides' inhibition mechanism towards Botrytis cinerea Pers provides basis for the mechanism of chitosan-oligosaccharides, the new biological pesticide.