Identification of Pseudomonas corrugata, the Causal Agent of Tomato Pith Necrosis, and Screening of Agrochemicals
Other Title
番茄髓壞疽病之病原菌Pseudomonas corrugata之鑑定與藥劑篩選
Journal
台灣農業研究
Journal Volume
75
Journal Issue
2
Start Page
293
End Page
306
ISSN
2790-086X
Date Issued
2026-06-09
Author(s)
Abstract
In 2014, tomato plants grown in a field located in the Waipu District, Taichung City, Taiwan, exhibited stunted growth and increased fruit abscission. Affected plants exhibited epidermal browning on the stems, and longitudinal sections of the stem revealed browning of the vascular bundles. Microscopic examination of the symptomatic stem tissues revealed abundant bacterial presence, indicating a bacterial infection. On nutrient agar, colonies of Pectobacterium carotovorum subsp. carotovorum, the known causal agent of bacterial soft rot, was isolated from symptomatic stem tissues. In addition, the unknown yellowish bacteria were also isolated. The yellowish bacteria were identified as Pseudomonas corrugata based on the Biolog identification system, physiological and biochemical characterizations, polymerase chain reaction (PCR) amplification using species-specific primer sets, and bacterial gene sequence analysis. Pathogenicity tests were conducted by inoculating the bacterial isolates into healthy tomato plants, which subsequently developed vascular bundle browning extending longitudinally along the stem, resembling the symptoms observed in the field. In cases of severe infection, pith necrosis was also observed. The same bacteria were successfully re-isolated from the symptomatic tissues, thereby fulfilling Koch’s postulates. This is the first report of P. corrugata infection on tomato in Taiwan. To manage the disease, an in vitro screening of commercial agrochemicals was conducted. Streptomycin, streptomycin + tetracycline, and thiophanate methyl + streptomycin produced distinct inhibitory zones against bacterial growth. Afterwards, no further tomatoes were planted in the field, and the disease did not recur.
在 2014 年，臺中市外埔區 1 處番茄田植株部分植株出現生長緩慢，並且果實易有落果的情形，罹病植株莖部表皮黑褐化，縱切莖部發現維管束褐化且蔓延，將受害莖部組織在光學顯微鏡下鏡檢具有大量細菌湧出，疑似細菌性病害。從罹病株分離病原菌，在營養培養基分離出番茄細菌性莖腐細菌 Pectobacterium carotovorum subsp. carotovorum 之外，另外分離出 1 種未知的淡黃色細菌，該未知細菌，經 Biolog 鑑定系統分析、細菌生理生化特性分析、專一性引子對鑑定以及細菌基因序列分析，將該菌鑑定為 Pseudomonas corrugata，將其接種至番茄植株，在莖部出現維管束褐化蔓延病徵，與田間所見相同，嚴重感染之植株，髓部可觀察到壞疽病徵產生，並可再分離出該細菌，完成科霍氏法則。此為 P. corrugata 感染番茄在臺灣之首次報導。為防治此細菌，在培養基進行市售農藥篩選試驗，以鏈黴素、鏈四環黴素及多保鏈黴素具有明顯的抑制細菌生長效果，並形成明顯的抑制圈。該田區之後未再繼續種植番茄，未再發生該病害。
Subjects
Tomato
Pith necrosis
Pseudomonas corrugate
Agrochemical screening
番茄
髓壞疽病
Pseudomonas corrugata
藥劑篩選
Publisher
農業部農業試驗所
Type
journal article
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