台灣甘藍黃葉病菌的鑑定及其對十字花科蔬菜的致病性

Identification for the Causal Agent of Cabbage Yellows in Taiwan and its Pathogenicity on Cruciferous Vegetable Crops

莊茗凱(M. K. Chuang) ； 李思儀(S. Y. Li) ； 黃振文(J. W. Huang)

《植物病理學會刊》 21卷1期 (2012/03) Pp. 29-38

https://doi.org/10.6649/PPB.201203_21(1).0004

摘要

西元2008年在雲林縣東勢鄉及2009年在苗栗縣卓蘭鎮等地區的夏季甘藍栽培田，發現甘藍植株下為葉黃化，呈現半側萎凋與枯死的現象。將罹病的植株根部縱切後，維管束有褐化、壞疽等病癥。自罹病甘藍植株組織分離，共獲得15個菌株（FOC-JR01~06與FOC-YL01~09），經柯霍氏法則測定結果，顯示它們對甘藍均具致病性。將FOC-JR01與FOC-YL08兩菌株分別接種於9種不同作物，結果發現兩株菌除會感染甘藍外，尚可感染芥藍與蕪菁。本病原菌在馬鈴薯葡萄糖瓊脂培養基的最適生長溫度為28℃，其生長初期菌絲為白色，隨後在光照之下逐漸轉變呈淡紫色，並可在試管內壁形成白色細小的菌絲結。本菌有三種孢子形態，包括大、小分生孢子及厚膜孢子；大分生孢子成鐮刀形，無色，2~4個隔膜（大多3個隔膜），大小7.9~33.3X1.0~6.4μm（平均20.6x3.7μm）；小分生孢子為橢圓或臘腸形，無色，大小6.1~13.9x1.4~6.4μm（平均10.0x3.9μm）；厚膜孢子近圓形，無色，大小4.7~13.5x4.6~14.3μm（平均9.1x9.45μm）。大小分生孢子皆著生於分生孢子梗的瓶狀枝上，小孢子呈假頭狀排列；厚膜孢子則於菌絲間生或頂生，或由大小孢子轉化而成。綜合上述菌株之形態特徵與病原性測定結果，配合它們分子生物學分析佐證資料，本研究確定台灣中南部甘藍黃葉病的病原菌為Fusarium oxysporum f. sp. conglutinans（Wollenweb.）W. C. Snyder and H. N. Hansen。利用人工病菌土進行接種試驗，發現將甘藍種子直接播種在含有菌量10^3、10^4及10^5（cfu/ml medium）的栽培介質中，28天後甘藍植株的發病率分別為33%、83%及86%；此外，將株齡21天的甘藍幼苗移植種於含有菌量250、500及1000（cfu/ml medium）的栽培介質中，21天後甘藍植株罹病率分別為93%、100%及100%；至於罹病度則分為47%、71%及76%。

關鍵字

甘藍黃葉病菌 ； 芥藍 ； 病原性 ； 蕪菁

並列摘要

Recently, cabbage yellows became severe in central Taiwan during summer season. The causal agent of cabbage yellows was isolated from diseased plants and infested soil. In this study, fifteen isolates FOC-JR01~06and FOC-YL01~09 were obtained, and identified as Fusarium oxysporum f. sp. conglutinans (Wollenweb.) W. C. Snyder and H. N. Hansen according to their pathogenicity test, morphological, and molecular characteristics. Pathogenicity test showed that isolates FOC-JR01 and FOC-YL08 had virulence on cabbage (cv. Summer Summit), Chinese kale (cv. Wai-Chun) and turnip (cv. Tsugaru-Beni). On potato dextrose agar, isolates FOC-JR01 and FOC-YL08 grew well at 24-32°C, but optimal at 28°C. Their colonies arc white then turn to purple color under 12hr-light per day and produce orange sporodochia. The pathogen is able to produce microconidia, macroconidia and chlamydospores. Microconidia produced abundantly from monophialides only in false heads, one-celled, hyaline, elliptical to allantoid, 6.1~13.9 x 1.4~6.4 μm (ave . 10.0 x 3.9 μm), Macroconidia produced from monophialides, hyaline, sickle-shaped, 2-4 septate (mostly 3-seplate), 7.9~33.3 x 1.0~6.4 μm (ave. 20.6 x 3.7 μm). Chlamydospores formed mostly in hyphae, terminal or intercalany, spherical to ovid, 4.7 ~13.5 x 4.6~14.3μm (ave. 9.10 x 9.45 μm). The disease incidences of cabbage plants in the infested media at population densities of 10^3, 10^4, and 10^5 (cfu/ml medium) were 33%, 83%, and 86%, respectively at 28 days after sowing seeds. However, the disease incidences of cabbage plants grown in the infested media at population densities of 250, 500, and 1000 (cfu/ml medium) were 93%, 100%, and 100%, respectively; and the disease severities were 47%,71%, and 76%, respectively at 2 1 days after transplanting 21-day-old seedlings in the greenhouse.

並列關鍵字

Fusarium oxysporum f. sp. conglutinans ； Chinese Kale ； Pathogenicity ； Turnip