Herbaspirillum huttiensis引起的羅勒細菌性葉枯病

Occurrence and identification of bacterial leaf blight on Basil found in Taiwan

2011～2012年，於高雄大寮及屏東等多處羅勒栽培區發現在羅勒新芽、葉緣水孔處出現水浸狀病徵，隨後水浸狀隨葉脈發展，逐漸出現褐化枯萎，嚴重時葉片掉落。莖部在採收傷口處往下的枝條呈現深褐色不規則壞疽，病斑向下蔓延導致植株萎凋。經組織分離及柯霍氏法則確認，此病徵是由具病原性的細菌所引起，病原細菌經由生理生化確認與Burkholderia屬細菌的特性相近，進而測試氧化酵素酶、精氨酸二水解酶、澱粉水解酶及果膠分解酶活性等，以及PCR確認，顯示危害羅勒之未知病原菌並非已知Burkholderia屬的植物病原菌。再經Biolog及碳源測定鑑定，確認該病原菌為Herbaspirillum huttiensis（Pseudomonas huttiensis）；再以16S rDNA定序鑑定，結果與GenBank中的Herbaspirillum huttiensis（accessionnumber NR114139.1）序列相似度達99 %。綜合上述，確認本病是由Herbaspirillum huttiensis引起的羅勒細菌性葉枯病。初步以濾紙擴散法在培養基上測試藥劑對此病原菌生長的抑制效果，顯示10種供試藥劑除三元硫酸銅對羅勒部份供試菌株生長不具抑制作用外，其他9種藥劑均有抑制效果，且以歐索林酸的效果最佳，抑制效果由強至弱依序為歐索林酸、鏈黴素、鋅錳乃浦、多保鏈黴素、鏈四環黴素、鹼性氯氧化銅、氫氧化銅、嘉賜黴素、嘉賜銅及三元硫酸銅。

"An unknown bacterial blight disease of basil was observed in southern Taiwan during 2011 and 2012. Disease symptoms were found on the whole plant, including the leaf, stem, and petal etc. The symptoms start off as brown to dark brown irregular spots on young sprouts, leaf margin and veins. The spots later coalesce and could lead to leaf dropping symptoms. When infecting the stems, the pathogen first appeared on cutting or pruning wounds and later expand downward, eventually causing the plant to wilt. A gramnegative, rod-shaped bacterium was consistently isolated from the diseased tissues. The pathogenicity of the isolates were confirmed by fulfilling Koch's postulates. The unknown bacterium was identified as Herbaspirillum huttiensis based on its physiological and biochemical characteristics, and identification using the Biolog GN MicroPlate Identification System, and sequencing of its 16S rDNA. A preliminary in vitro agrochemical screening indicated that oxolinic acid was more effective in controlling the pathogen."