ClO2对马铃薯块茎软腐病菌的控制效果及作用机理

Inhibitory Effect and Mechanism of ClO2 on Pectobacterium carotovorum subsp.carotovorum of Soft Rot on Potato Tubers

以马铃薯块茎软腐病原菌Pectobacterium carotovorum subsp.carotovorum(Pcc)为研究对象,探究离体条件下二氧化氯(ClO2)对其控制效果及作用机理,采用扫描电镜(SEM)和透射电镜(TEM)对其进行室内生物测定,观察菌体形态和菌体超微结构,并通过马铃薯体内接种Pcc对马铃薯块茎软腐病进行防治效果评价。结果表明,离体条件下,Pcc对ClO2具有较好的敏感性,其毒力回归式为y=4.4868+7.6827x,EC50和EC90分别为0.2524μg·mL^-1和0.4872μg·mL^-1,ClO2处理对马铃薯软腐病原菌Pcc的生长具有显著的抑制作用,且抑制效果存在浓度效应,0.52μg·mL^-1 ClO2对Pcc的相对抑制率最高;扫描和透射电镜观察发现,ClO2处理后Pcc菌体形态发生异常,个别菌体胞壁皱褶、破裂,内容物渗出,细胞壁与细胞膜出现分离,且鞭毛消失,生长受到抑制。体内试验表明,ClO2处理可显著降低马铃薯薯块的发病率和病斑扩展速度,其中以低温条件下80μg·kg^-1效果最佳。综上所述,ClO2对Pcc具有良好的抑菌特性,该研究可为ClO2在马铃薯采后病害防治中的安全高效应用提供科学的理论依据。

The inhibitory effect and mechanism of chlorine dioxide(ClO2)against P.carotovorum subsp.carotovorum(Pcc)of soft rot on potato were investigated.The morphology and ultrastructure of the bacteria were observed by indoor bioassay,scanning electron microscopy(SEM)and transmission electron microscopy(TEM)after treated with ClO2 in vitro test,and effect of ClO2 treatment on soft rot of potato tuber inoculated with Pcc pre-treatment were also evaluated.The results showed that,potato soft rot pathogen was sensitive to ClO2,in which the virulence of regression,EC50 and EC90 were y=4.4868+7.6827x,0.2524μg·mL^-1 and 0.4872μg·mL^-1 respectively.The growth of soft rot pathogen was significantly inhibited by ClO2 in a concentration dependent way,and the relative inhibition rate of 0.52μg·mL^-1 ClO2 treatment was the highest.The Pcc pathogen cells changed from normal straight rod to round or approximate oval shape.The cell walls of individual were wrinkled,ruptured with content exudation and were separated from the cell membrane.SEM and TEM showed that,the flagellum was disappeared,and the growth was inhibited after ClO2 treatment.Results from vivo test indicate that ClO2 was effective to control the soft rot of potato tubers with Pcc,among which 80μg·kg^-1 of ClO2 concentration at low temperature was the optimal condition.These findings suggested that,ClO2 had direct fungitoxic activity against the pathogen and could be a potential green fungicide to control postharvest diseases in potatoes.