菜豆萎凋病菌之生物特性及其病原性

The Characteristics of a Causal Agent of Common Bean wilt and Its Pathogenicity

李宜欣(I. H. Lee) ； 林宗俊(T. C. Lin) ； 黃振文(J. W. Huang)

《Fungal Science》 26卷1期 (2011/08) Pp. 7-21

https://doi.org/10.7099/FS.201108.0007

摘要

西元2001年，於南投縣集集鎮的菜豆(Phaseolus vulgaris L.)栽培田發生植株萎凋死亡的現象，隨後也在埤頭、魚池及頭社等地區發現菜豆植株萎凋、黃化的病徵。受害植株地下部的根系大多發育不良，根莖部的維管束褐化，病勢蔓延至葉片，繼而全葉枯黃脫落。自罹病菜豆分離病原菌，共獲得FOP-044、FOP-061及FOP-091等12個菌株。各菌株培養在馬鈴薯葡萄糖瓊脂培養基斜面，其菌落顏色為白色或粉橘紅色，可在試管壁形成細小的菌絲結。多數菌株的菌落生長基質呈深紫色；部分菌株會出現數目不等的深墨綠色(dark bluish green)菌核體(sclerotial bodies)。孢子有大孢子、小孢子及厚膜孢子等三種：大孢子呈鐮刀形，具典型的足細胞，大小3.0-6.0×25.0-35.0 μm（平均4.5×30.0 μm），以3-4個隔膜的大孢子較多；小孢子為橢圓或臘腸形，無色，大小2.0-3.8×3.8-11.4 μm（平均2.9×7.6μm）；厚膜孢子大多形成於菌絲間，亦有頂生者，球形至橢圓形，大小2.0-4.0×6.0-15.0 μm（平均3.0×10.5 μm）。大小分生孢子皆著生於分生孢子梗(conidiophore)的瓶狀枝(phialide)上，小孢子呈假頭狀排列。孢子堆呈橙黃色、平鋪型或粒狀型。將FOP-044與FOP-091菌株接種於16種不同作物，結果發現僅菜豆可被其感染。另外取Fusarium oxysporum其他分化種的菌株接種於菜豆上，發現只有由罹病菜豆植株分離到的菌株才能感染菜豆。依上述菌株之形態特徵與病原性，參照Booth氏、Nelson氏等及Gerlach氏與Nirenberg氏之Fusarium分類系統，將引起菜豆萎凋病之病原菌鑑定為F. oxysporum Schlechtend.: Fr. f. sp. phaseoli J. B. Kendrick and W. C. Snyder。本菌最適生長溫度介於24至28℃之間。最適分生孢子發芽的酸鹼值為pH6。最適發病溫度介於24至28℃之間。利用浸根接種法與病菌土接種法，發現菜豆萎凋病的罹病度，會隨著接種菌量濃度的增加而越趨嚴重。菜豆品種間以扁圓莢有絲－屏東大莢最為耐病；而以圓莢無筋絲83-10-28最為感病。。

關鍵字

Fusarium oxysporum f. sp. phaseoli ； 菜豆萎凋病

並列摘要

In 2001, a disease of common bean (Phaseolus vulgaris L.) was observed in central Taiwan fields. The fungus traversed the vascular bundles throughout almost the entire stem and extended into the branches and the petioles of the leaves. The vascular bundles were conspicuously discolored and extended from the root. In the early stage the color of the leaves turn to bright yellow, later to dark brown. The leaves finally dried up and dropped off. The fungus, Fusarium oxysporum, was consistently isolated from all affected plants. Twelve isolates of the fungus isolated from the diseased tissues were able to cause a wilt disease of common bean, but did not cause any visible symptom in other crops, while other formae speciales of F. oxysporum could not cause a wilt disease of common bean after inoculation in greenhouse. According to the morphological characteristics and pathogenicity tests, the pathogen was identified as Fusarium oxysporum f. sp. phaseoli. The fungus produced the blue-purple colony. Sporodochia appeared discrete or confluent, straw or orange. Sclerotial bodies were sparse to abundant, dark bluish green. Microconidia were produced abundantly from monophialides only in false heads, generally single-celled, elliptical to allantoid, 2.0-3.8×3.8-11.4 μm. Macroconidia were produced abundantly from monophialides, 3.0-6.0×25.0-35.0 μm, on branched or unbranched conidiophores, slightly sickle-shaped, thin-walled, and delicate, with a foot-shaped basal cell, mostly 3-5 septate. Chlamydospores were formed mostly in hyphae, terminal or intercalary, solitary, in pairs or in chains, 2.0-4.0×6.0-15.0 μm. The optimum temperature for mycelial growth and conidial germination of F. oxysporum f. sp. phaseoli isolates FOP-044 and FOP-091 was at 24-28℃, and for chlamydospore germination was at 24℃. The optimum pH value for conidial germination of two isolates was at 6. The appropriate temperature for infecting common bean plants by these isolates was at 24-28℃. The common bean cultivar, Pingdon-big-pod, was the most tolerant while the cultivar, 83-10-28, was the most sensitive to Fusarium wilt among the tested cultivars..

並列關鍵字

common bean ； Fusarium oxysporum f. sp. Phaseoli ； Fusarium wilt