| China is a powerful agricultural country.Yield and quality of agricultural products are related closely to the national economy.The study mainly evaluated the biocontrol effects of antagonistic microorganisms on pathogenic fungi in fruits,vegetables and crops,so as to apply our laboratory results into practical application in the aspects of biological control.In the study,the paenibacillus polymyxa HT16 was choosed to determine the inhibitory effects on the common pathogenic fungi using the confrontation method.The result showed that the inhibition activity was more than 50%.And the spore germination and mycelial growth were inhibited significantly.Using the response surface methodology,an economic efficient medium was screened.The main factors(potato,ammonium sulfate,sucrose)were also determined by Plackett-Burman design.With the Box-Behnken design,the maximum response value was obtained.The optimal fermentation medium was as follows: 30%potato,0.4%ammonium sulfate,1.5% sources,0.05% K2HPO4,0.05% MgSO4·7H2O and 0.1% bean cake powder at pH 6.5.The inhibition zone diameter of P.polymyxa HT16 against pathogenic fungi under the optimized culture medium was improved 1 times compared to that of the original medium.And the number of the spores was improved 2.5 times.After the study of HT16 against pathogenic fungi in postharvest storage,we found that the rot disease incidence in grapes,pears and tomatos declined significantly.the prevetion effect of The crude protein of HT16 showed the most significant inhibitory effect than HT16 fermented liquid and cell-free suspension.The study about inhibitory mechanism of HT16 showed that it significantly inhibited the spore germination,destroyed the mycelial growth.After the crude protein was diluted,it still has the antifungal ability.Therefore,P.polymyxa HT16 is expected to be a good biological control agents,and will have a broad application prospect in diseases control of postharvest fruits and vegetables or in agriculture. |
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