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2014—2015年,在中国山东、山西、河北、河南、辽宁等省的黄瓜茎叶上发生了毁灭性的细菌性软腐病,造成了黄瓜产业严重的经济损失。黄瓜叶片、茎、叶柄和果实表面出现流胶;茎基部呈深褐色进而出现湿腐。受侵染的黄瓜叶边缘出现黄斑和湿腐症状,并逐渐扩散至叶片中心。从受侵染组织中分离出45个细菌菌株,在形态学特性鉴定、生理学、生物化学和16Sr RNA基因序列分析的基础上,将病原体鉴定为胡萝卜软腐果胶杆菌(Pectobacterium carotovorum)。多位点序列分析(MLSA)证实,分离菌株是胡萝卜软腐果胶杆菌巴西亚种[Pectobacterium carotovorum subsp.brasiliensis(Pcb)],病原菌归入进化枝II。重新分离获得与原始菌株相同的菌株,证实了分离菌株的致病力。寄主范围测试表明,该菌株具有广泛的寄主范围。目前为止,这是对Pcb引起的黄瓜软腐病——这一对黄瓜生产具有重要经济影响的病害在中国乃至全球范围内的首次报道。
In 2014-2015, devastating bacterial soft rot disease occurred on the stems and leaves of cucumber in the provinces of Shandong, Shanxi, Hebei, Henan and Liaoning in China, causing serious economic losses to the cucumber industry. Cucumber leaves, stems, petioles and fruit appear on the surface of plastic flow; stem base was dark brown and then wet rot. The affected cucumber leaves showed macular and wet rot on the edges and gradually spread to the center of the leaves. Forty-five bacterial strains were isolated from infected tissues and identified as Pectobacterium carotovorum on the basis of morphological characterization, physiology, biochemistry and 16S rRNA gene sequence analysis. Multiple locus sequence analysis (MLSA) confirmed that the isolated strain was Pectobacterium carotovorum subsp. Brasiliensis (Pcb), and the pathogen was classified into clade II. The same strain as the original strain was obtained by re-isolation, confirming the virulence of the isolated strains. Host range testing showed that this strain has a wide host range. So far, this is the first report in China and around the world of the disease caused by Pcb-induced cucumber soft rot - an important economic impact on cucumber production.