甜瓜粉霉病病原菌鉴定及三种药物对病原菌的体外抑制作用

Identification of Fungal Pathogen Causing Pink Rot of Muskmelons and Inhibitory Effects of Three Chemicals on the Fungal Pathogen in Vitro

为明确甜瓜粉霉病真菌病原菌,以自然发粉霉病的甜瓜果实为研究对象,通过组织分离和单孢纯化得其病原,并进行rDNA-ITS克隆测序、BLAST比对分析,构建系统发育树,结合形态学特征,鉴定该病原菌为粉红单端孢(Trichothecium roseum)。以菌丝扩展和孢子萌发抑制率、毒力回归方程、半最大效应浓度(EC50)、最小抑菌浓度(MIC)为指标,通过体外试验研究了硅酸钾、香芹酚和月桂酸三种药物对T.roseum的抑菌效果。结果表明:硅酸钾、香芹酚和月桂酸浓度依次为2.00、0.08和0.16g/L时,三种药物对T.roseum的菌丝扩展抑制率分别为65.94%、68.60%和80.41%,对应的EC50分别为1.39、0.71和0.90g/L;硅酸钾、香芹酚和月桂酸浓度依次为2.00、0.08和0.16g/L时,药物对T.roseum的孢子萌发抑制率为61.24%、70.04%和77.53%,对应的EC50分别为1.25、0.05和0.09g/L。硅酸钾、香芹酚和月桂酸三种药物的MIC分别是1.50、0.08和0.12g/L。由此可知:三种药物均可体外抑制T.roseum,具有控制甜瓜粉霉病的潜力。

In order to identify the fungal pathogen causing pink rot,the muskmelon fruit( cv.Yujingxiang) of natural pink rot was used as the material,and the pathogen was isolated and purified by the method of tissue isolation and single spore isolation respectively.The rDNA- ITS were cloned and sequenced,then BLAST analyzed,finally a phylogenetic tree was constructed. Combined with morphological characteristics,the pathogen was identified as Trichothecium roseum.Furthermore,the inhibition rate of mycelial extension and spore germination,virulence regression equation,concentration for 50% of maximal effect( EC50 ) and minimum inhibitory concentration( MIC) were examined to compare the inhibitory effection T.roseum in vitro among three chemicals of potassium silicate,carvacrol and lauric acid.The results showed that the inhibition rates of mycelium expansum were 65.94%,68.60% and 80.41%,and the EC50 of them were 1.39,0.71 and 0.90 g /L,respectively,when the concentrations of three chemicals were 2.00,0.08 and 0.16 g /L,respectively.Moreover,the spore germination inhibition rate of T.roseum were 61.24%,70.04% and 77.53%,EC50 were 1.25,0.05 and 0.09 g /L,respectively.In addition,the MIC of three chemicals were 1.50,0.08 and 0.12 g /L,respectively.All these results suggest that potassium silicate,carvacrol and lauric acid can inhibit T.roseum in vitro and they have the potential to control pink rot in muskmelon fruit.