由Pseudomonas viridiflava引起的十字花科蔬菜細菌性葉枯病

Cruciferous bacterial leaf blight: a new disease caused by Pseudomonas viridiflava

許秀惠(S. H. Hseu) ； 許馨云(S. Y. Hsu) ； 蔡叔芬(S. F. Tsai) ； 曾怡蓉(Y. J. Tseng)

《植物病理學會刊》 24卷2期 (2015/06) Pp. 119-130

https://doi.org/10.6649/PPB.201506_24(2).0005

摘要

民國102年初春在高雄梓官的蔬菜栽培區發現尼龍白菜葉片上出現水浸狀病斑，之後形成壞疽病斑，在高濕環境下葉片呈現輕微軟腐且組織褐化、壞死的不規則斑點，但在乾燥環境下則僅呈現褐化的不規則斑。後續2年期間陸續在台灣東北部宜蘭三星，北部新北市地區，中部南投仁愛、信義等地的甘藍、青花菜、紫花椰菜、結球白菜、黃金結球白菜、黃花芥菜、白花芥菜與大頭菜等十字花科蔬菜上發現同樣的病徵。經組織分離、菌株純化及柯霍氏法則確認本病係由細菌所引起。經生理生化測定與Biolog鑑定結果與Pseudomonas viridiflava及P. syringae 相近，但在碳源的利用顯示分離自十字花科的供試病原菌無法利用蔗糖產生酸性產物，此特性與P. vidiflava相同。以對P. viridiflava具專一性的引子對20F/20R進行PCR鑑定，供試31株菌株於440 bp處均產生專一性條帶，但供試P. syringae菌株則未產生條帶。再以16S rDNA定序鑑定，結果與GenBank 中的Pseudomonas viridiflava strain BC 2495（accession number HM190218）相似度達99％。綜合上述，確認本病是由Pseudomonas viridiflava（Burkholder）Dowson 1939引起的細菌性葉枯病，為台灣十字花科蔬菜上的首次紀錄。由接種試驗顯示該病原菌可感染供試22種十字花科蔬菜。初步以濾紙擴散法在培養基上測試藥劑對本病原菌的抑制效果，結果顯示供試10種藥劑均有抑制作用，其中以鏈四環黴素、嘉賜黴素及多保鏈黴素的效果較佳。

關鍵字

十字花科蔬菜 ； 細菌性葉枯病 ； 室內藥劑篩選

並列摘要

An unknown disease was first noticed on Pak choy in early spring in Zhi quan（梓官）, Kaoshiung 2013. The symptoms began with small water soaked lesions on the leaf and gradually expanded. In humid conditions, the lesions became slimy, rotten, and eventually the whole leaf collapsed. A field survey was conducted from 2013 to 2015, the disease was commonly found on cruciferous vegetables such as cabbage, cauliflower, pruple cauliflower, Chinese cabbage, mustards and kohlrabi in the north-eastern, northern and central areas. The pathogen was isolated from diseased tissues to get pure culture, and Koch's postulates were fulfilled. The pathogen was identified as Pseudomonas species (viridiflava or syringae) by physiological and biochemical characterization and Biolog system; however, based on the incapability of utilizing sucrose, the pathogen was identified as P. viridiflava. A total of 31 strains collected from the fields showed a 440 bp fragment specifically amplified by the 20F/20R primers in a polymerase chain reaction. The 16S rDNA nucleotide sequences of the tested strains showed that they were 99% identical to the one of P. viridiflava BC2459 (accession number HMI190218). Twenty two cruciferous plants were inoculated and showed to be susceptible to the pathogen in the green house inoculation assays. Ten agrochemicals were tested by disc diffusion assays, and all of them showed inhibitory activities against the pathogen; among them, streptomycin + tetracycline, kasugamycin, and polyoxin had better efficacy in inhibiting bacterial growth on the culture medium.

並列關鍵字

cruciferous vegetables ； Pseudomonas viridiflava ； bacterial leaf blight ； agrochemical screening