Bacterial fruit blotch caused by Acidovorax citrulli is a serious threat to cucurbit industry worldwide.The pathogen is seedtransmitted,so seed detection to prevent distribution of contaminated seed is crucial in dise...Bacterial fruit blotch caused by Acidovorax citrulli is a serious threat to cucurbit industry worldwide.The pathogen is seedtransmitted,so seed detection to prevent distribution of contaminated seed is crucial in disease management.In this study,we adapted a quantitative real-time PCR(qPCR)assay to droplet digital PCR(ddPCR)format for A.citrulli detection by optimizing reaction conditions.The performance of ddPCR in detecting A.citrulli pure culture,DNA,infested watermelon/melon seed and commercial seed samples were compared with multiplex PCR,qPCR,and dilution plating method.The lowest concentrations detected(LCD)by ddPCR reached up to 2 fg DNA,and 102 CFU mL–1 bacterial cells,which were ten times more sensitive than those of the qPCR.When testing artificially infested watermelon and melon seed,0.1%infestation level was detectable using ddPCR and dilution plating method.The 26 positive samples were identified in 201 commercial seed samples through ddPCR,which was the highest positive number among all the methods.High detection sensitivity achieved by ddPCR demonstrated a promising technique for improving seed-transmitted pathogen detection threshold in the future.展开更多
由燕麦噬酸菌西瓜亚种(Acidovorax avenae subsp.citrulli,简称Aac)引起的西瓜、甜瓜细菌性果斑病(Bacterial Fruit Blotch,简称BFB)是西瓜、甜瓜生产上的一种毁灭性病害。目前资料上报道的一些药剂对果斑病菌的防效不尽一致,为明确这...由燕麦噬酸菌西瓜亚种(Acidovorax avenae subsp.citrulli,简称Aac)引起的西瓜、甜瓜细菌性果斑病(Bacterial Fruit Blotch,简称BFB)是西瓜、甜瓜生产上的一种毁灭性病害。目前资料上报道的一些药剂对果斑病菌的防效不尽一致,为明确这些药剂的防治效果及筛选更有效的药剂,试验采用抑菌圈法测定了63种杀菌剂对西瓜、甜瓜细菌性果斑病菌的室内毒力作用。结果表明:72%农用硫酸链霉素SPX等11种药剂对西瓜、甜瓜细菌性果斑病菌具有较好的抑制效果,抑菌圈平均直径>10.0mm;不同厂家生产的农用链霉素在相同浓度下抑菌效果明显不同;西瓜菌株和甜瓜菌株对同一药剂的敏感性也有较大差异。展开更多
细菌性果斑病(Bacterial Fruit Blotch,BFB)是西瓜和甜瓜的重要病害。本实验从发病甜瓜果实上分离得到致病菌株MH21,经鉴定为燕麦食酸菌西瓜亚种(Acidovorax avenaesubsp.citrulli)。利用转座子Mini-Tn5构建MH21菌株的突变体库,Souther...细菌性果斑病(Bacterial Fruit Blotch,BFB)是西瓜和甜瓜的重要病害。本实验从发病甜瓜果实上分离得到致病菌株MH21,经鉴定为燕麦食酸菌西瓜亚种(Acidovorax avenaesubsp.citrulli)。利用转座子Mini-Tn5构建MH21菌株的突变体库,Southern印迹杂交结果显示Mini-Tn5在菌株MH21染色体上可随机、单拷贝插入。通过浸种处理甜瓜种子进行突变体的致病性检查,筛选得到1株致病性完全丧失的突变体M543。对M543中转座子插入基因的克隆和测序表明其突变基因为燕麦食酸菌Ⅲ型分泌系统(TTSS)中的保守基因hrcR。推测菌株MH21中hrcR基因编码的蛋白定位于细菌内膜,是分泌通道主要成分之一。hrcR基因互补菌株的致病性检查结果显示其致病力恢复到野生型的84%。研究同时发现hrcR基因突变后MH21菌株丧失了在烟草上诱导过敏性坏死反应的能力。本研究从遗传学角度说明TTSS是西甜瓜果斑病菌致病性的重要因子。展开更多
基金supported by the the National Key Research and Development Program of China (2017YFD0201602)the National Natural Science Foundation of China (31401704)the Beijing Academy of Agriculture and Forestry Foundation, China (KJCX20180203)
文摘Bacterial fruit blotch caused by Acidovorax citrulli is a serious threat to cucurbit industry worldwide.The pathogen is seedtransmitted,so seed detection to prevent distribution of contaminated seed is crucial in disease management.In this study,we adapted a quantitative real-time PCR(qPCR)assay to droplet digital PCR(ddPCR)format for A.citrulli detection by optimizing reaction conditions.The performance of ddPCR in detecting A.citrulli pure culture,DNA,infested watermelon/melon seed and commercial seed samples were compared with multiplex PCR,qPCR,and dilution plating method.The lowest concentrations detected(LCD)by ddPCR reached up to 2 fg DNA,and 102 CFU mL–1 bacterial cells,which were ten times more sensitive than those of the qPCR.When testing artificially infested watermelon and melon seed,0.1%infestation level was detectable using ddPCR and dilution plating method.The 26 positive samples were identified in 201 commercial seed samples through ddPCR,which was the highest positive number among all the methods.High detection sensitivity achieved by ddPCR demonstrated a promising technique for improving seed-transmitted pathogen detection threshold in the future.
文摘由燕麦噬酸菌西瓜亚种(Acidovorax avenae subsp.citrulli,简称Aac)引起的西瓜、甜瓜细菌性果斑病(Bacterial Fruit Blotch,简称BFB)是西瓜、甜瓜生产上的一种毁灭性病害。目前资料上报道的一些药剂对果斑病菌的防效不尽一致,为明确这些药剂的防治效果及筛选更有效的药剂,试验采用抑菌圈法测定了63种杀菌剂对西瓜、甜瓜细菌性果斑病菌的室内毒力作用。结果表明:72%农用硫酸链霉素SPX等11种药剂对西瓜、甜瓜细菌性果斑病菌具有较好的抑制效果,抑菌圈平均直径>10.0mm;不同厂家生产的农用链霉素在相同浓度下抑菌效果明显不同;西瓜菌株和甜瓜菌株对同一药剂的敏感性也有较大差异。
文摘细菌性果斑病(Bacterial Fruit Blotch,BFB)是西瓜和甜瓜的重要病害。本实验从发病甜瓜果实上分离得到致病菌株MH21,经鉴定为燕麦食酸菌西瓜亚种(Acidovorax avenaesubsp.citrulli)。利用转座子Mini-Tn5构建MH21菌株的突变体库,Southern印迹杂交结果显示Mini-Tn5在菌株MH21染色体上可随机、单拷贝插入。通过浸种处理甜瓜种子进行突变体的致病性检查,筛选得到1株致病性完全丧失的突变体M543。对M543中转座子插入基因的克隆和测序表明其突变基因为燕麦食酸菌Ⅲ型分泌系统(TTSS)中的保守基因hrcR。推测菌株MH21中hrcR基因编码的蛋白定位于细菌内膜,是分泌通道主要成分之一。hrcR基因互补菌株的致病性检查结果显示其致病力恢复到野生型的84%。研究同时发现hrcR基因突变后MH21菌株丧失了在烟草上诱导过敏性坏死反应的能力。本研究从遗传学角度说明TTSS是西甜瓜果斑病菌致病性的重要因子。
