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標題: 無病原性尖鐮胞菌在防治胡瓜及長豇豆萎凋病上之探討
Study of nonpathogenic Fusarium oxysporum in controlling Fusarium wilt of cucumber and asparagus bean
作者: 王照仁
Wang, Zhao-Ren
關鍵字: 無病原性尖鐮胞菌
nonpathogenic Fusarium oxysporum
Fusarium wilt of cucumber
hypocotyl cutting inoculation method
Fusarium wilt of asparagus bean
GUS gene
出版社: 植物病理學系所
摘要: 無病原性尖鐮胞菌菌株Fo366經種子粉衣與育苗介質混菌法導入胡瓜植株後,具有延緩胡瓜萎凋病病勢發展的能力,但仍無法保護胡瓜至採收後期。本論文主要目的在於開發剪胚軸的方式將Fo366導入胡瓜植株中,以提升其防治效果;擴大Fo366的防治對象,是否亦可抑制其他作物萎凋病;以及探討Fo366可能的防病機制。在溫室中,以種子粉衣、育苗介質混菌及剪胚軸接種法將Fo366導入胡瓜內,比較三者防治胡瓜萎凋病的效果,結果指出剪胚軸接種法最具防治效果,頗具潛力來防治胡瓜萎凋病發病至採收後期。另以育苗介質混菌法將Fo366導入長豇豆與菜豆植株中,發現Fo366對長豇豆萎凋病亦具有防病能力,但對菜豆萎凋病則否。換句話說,Fo366並非對所有作物都具有防治功效。試驗不同濃度Fo366對長豇豆萎凋病的防治效果,結果顯示Fo366的族群密度,必須高於病原菌的10倍以上,才有防治效果。利用剪胚軸接種法將Fo366導入胡瓜植株內2週後,再以剪根的方式強制導入胡瓜萎凋病菌,在此情形下,接種Fo366並不能延緩萎凋病病勢發展。因此推論Fo366的防病機制可能是競爭作用。本研究嘗試將GUS基因轉入Fo366中,以便更直接的觀察並區分病原性與無病原性尖鐮胞菌於植物組織中的纏據與分布情形。本研究另篩選其他來源之無病原性尖鐮胞菌(Fo159、Fo276和Fo501),以育苗介質混菌法導入長豇豆中,結果透露此三個菌株對長豇豆萎凋病皆具有抑病現象,尤其Fo276的抑病效果最優。
The nonpathogenic Fusarium oxysporum Fo366 had been demonstrated that it could delay the symptom expression of Fusarium wilt of cucumber by using seed coating and substrate infestation inoculation methods, but it could not guarantee a good yield to cucumber plants. The purposes of this thesis were to improve the protection efficacy by using a hypocotyl cutting inoculation method to preinoculate Fo366 into cucumber; to explore if Fo366 could be used for controlling other form species of F. oxysporum; and to study the possible mechanisms of biocontrol of Fo366. In greenhouse, three inoculation methods of seed coating, substrate infestation and hypocotyl cutting were compared on the effect of controlling Fusarium wilt of cucumber. The results indicated that the hypocotyl cutting method was the best one and its protection efficacy might last until harvest period. Moreover, Fo366 was also introduced into asparagus bean and snap bean by substrate infestation inoculation method and resulted that Fo366 performed well on inhibiting Fusarium wilt of asparagus bean, but not snap bean. Different populations of Fo366 were tested to control Fusarium wilt of asparagus bean and the results indicated that the disease control could only be achieved when the population of Fo366 was 10 times larger than that of pathogen population. In addition, Fo366 applied to cucumber roots could not delay symptom expression induced by the pathogen (F. oxysporum f. sp. cucumerinum) applied directly into the stem of plants 14 days later by using root-pruning inoculation method. Therefore, the possible mechanisms of disease protection might be the competition between pathogenic and nonpathogenic F. oxysporum for infection site or something else. Furthermore, the GUS gene was transferred into Fo366 in order to observe the distribution and colonization of Fo366 in plant tissue directly under microscope. More nonpathogenic Fusarium oxysporum isolates, Fo159, Fo276 and Fo501, (especially Fo276) had been also demonstrated that it could delay the development of Fusarium wilt of asparagus bean by using substrate infestation inoculation method.
Appears in Collections:植物病理學系



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