比較分離自葡萄園之Colletotrichum spp.菌株對葡萄之致病力

比較所蒐集之不同分離來源的Colletotrichum spp.菌株對「巨峰」葡萄（Vitis vinifera × V. labrusca, 'Kyoho'）致病力（virulence），在離果的葡萄果粒的接種試驗結果顯示（in vivo），Colletotrichum viniferum致病力最強，無論果粒有或無傷口，皆可造成顯著且大範圍之晚腐病病斑，且葡萄果分離株致病力有大於葉分離株的趨勢；Colletotrichum fructicola次之，有趣的是，分離自葡萄園內的牛筋草（Eleusine indica）分離株致病力高於葡萄果或葉分離株；Colletotrichum tropicale致病力最低，本研究中的菌株都需要藉由傷口才能感染果粒。另以C. fructicola與C. tropicale進一步做病原性測試，在田間葡萄幼果的接種試驗中（in planta），以C. fructicola菌株接種的果串在轉色後皆能成功發展出晚腐病病徵，其中牛筋草分離株接種的果串發病率以及病徵表現皆高於葡萄分離株的，而以C. tropicale接種的果串則未觀察到晚腐病的病徵；在接種葡萄全植株的試驗中，無論哪個菌株接種後的植株葉片或其他部位皆無出現明顯病徵。本研究為C. fructicola在台灣感染葡萄之首篇報導，同時確認C. fructicola可感染牛筋草，造成牛筋草水浸狀與褐化，進一步推論C. fructicola在田間可以牛筋草為替代寄主（alternative host），並可能在葡萄葉片上腐生，伺機感染葡萄果實，直至轉色期前後開始危害葡萄果實造成晚腐病。

關鍵字

葡萄晚腐病； Colletotrichum viniferum ； Colletotrichum fructicola ； Colletotrichum tropicale ；致病力

並列摘要

Virulence of Colletotrichum viniferum, Colletotrichum fructicola, and Colletotrichum tropicale from different isolation sources were compared on grapes (Vitis vinifera). In vivo pathogenicity test on the detached grape berries showed that C. viniferum was the strongest virulent species, which could cause significant and larger spots of ripe rot on grape berries with or without wounds. Moreover, the virulence of fruit isolates seems to be stronger than that of the leaf isolates; C. fructicola was ranked second in virulence. Interestingly, the virulence of the C. fructicola isolate from goose weed (Eleusine indica) was stronger than other isolates from grape fruits and leaves; C. tropicale was the lowest virulent species, and all the isolates in this study required wounds to infect berries. In addition, in planta pathogenicity tests of C. fructicola and C. tropicale were performed. In young grapes inoculation test, only berries inoculated with isolates of C. fructicola could develop the typical ripe rot disease symptoms after veraison. The disease rate and symptoms were higher and severer with C. fructicola isolated from goose weed than those from grape isolates, while no obvious symptoms with C. tropicale isolates. As for whole potted plants inoculation test, no obvious disease symptoms appeared on leaves or other parts of plants inoculated with any of the selected isolates of C. fructicola and C. tropicale. To our knowledge, this study is also the first report of goose weed leaf anthracnose caused by C. fructicola, which showed water-soaked and browning symptoms on leaf. These data suggest that, in the field, goose weeds could be an alternative host of C. fructicola. C. fructicola might live in a saprophytic life on grape leaves, waiting for chances to infect grape berries.

並列關鍵字

Grape ripe rot ； Colletotrichum viniferum ； Colletotrichum fructicola ； Colletotrichum tropicale ； Virulence test

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