透過您的圖書館登入
IP:3.81.221.121
  • 期刊
  • OpenAccess

Fusarium oxysporum f. sp. koae引起造林地台灣相思樹之萎凋病

Decline of Acacia confusa in Plantations Caused by Fusarium oxysporum f. sp. koae in Taiwan

摘要


相思樹(Acacia confusa Merr.)為臺灣重要的原生造林樹種。2019年間,在南投兩處相思樹造林地持續觀察到樹木萎凋之病徵。先前研究已發現,相思樹苗木維管束萎凋病的植株中,可分離到病原菌Fusarium oxysporum f. sp. koae。本研究主要在探討,造林地內相思樹呈現萎凋病徵之原因,與相思樹苗期維管束萎凋病是否為相同病原菌所引起,並探討該病原菌經由莖部侵染的可能性。為此,本研究自造林地感病相思樹樣本進行潛在病原菌的分離培養,得到可能的病原菌菌株Fusarium sp.。經由核醣體核酸的非轉錄基因間隔區序列(nuclear ribosomal DNA intergenic spacer, IGS)比對,本病原菌與F.oxysporum f. sp. koae有超過99%的相似度。進一步將此病原菌菌株對相思樹苗木進行接種試驗,結果顯示本研究分離之F. oxysporum f. sp. koae菌株,可成功經由莖部傷口感染相思樹苗木,造成萎凋之病徵;並可於感病組織上,成功回分接種之F. oxysporum f. sp. koae菌株,完成柯霍氏法則。經由兩重複病原菌接種試驗可發現,接種F. oxysporum f. sp. koae的相思樹苗木,其植株呈現缺水萎凋之葉片比率高於健康植株,顯示F. oxysporum f. sp. koae為造成相思樹造林地樹木萎凋之潛在病原菌,且可經由莖部傷口感染植株。

並列摘要


Acacia confusa Merr. is one of the most important native trees used for afforestation in Taiwan. The wilt symptoms were observed in the two Acacia-plantations in Nantou in 2019. According to the previous study, the fungal pathogen Fusarium oxysporum f. sp. koae was isolated from the A. confusa seedlings with vascular wilt symptoms. The purpose of this study was to investigate the agent causing wilt symptoms in the plantations and try to identify if the pathogen was the same as the vascular wilt of A. confusa seedlings. One potential Fusarium sp. was consistently isolated from the wilted Acacia trees in the plantations for further inoculation test. This fungus was identified by nuclear ribosomal DNA intergenic spacer (IGS) sequences as F. oxysporum f. sp. koae with more than 99% similarities. The A. confusa seedlings were inoculated and successfully infected by the isolate of F. oxysporum f. sp. koae through wounds of stems and exhibited wilt symptoms. Furthermore, the same fungus was further isolated from the inoculated seedlings to complete Koch's postulates. By two trails of inoculation tests, the percentage of wilted leaves of the inoculated Acacia seedlings was higher than the control ones. The results indicated that F. oxysporum f. sp. koae was a potential pathogen causing wilt symptoms in the Acacia-plantations and may infect through wounds of stems.

延伸閱讀