- 期刊
台灣廣葉杉萎凋病相關長喙殼菌之鑑定
Identification of Ophiostomatoid Fungi Associated with Chinese Fir Wilt in Taiwan
摘要
民國91年夏天，台灣中部多處林地，包括北埔、卓蘭、東勢、和平、仁愛、埔里、水里及阿里山地區之廣葉杉相繼出現萎凋枯死的現象。由杉木罹病植株分離到五個到表性菌株，完成柯霍氏法則試驗後，確定病原性。然後依造個菌株的無性世代種類與產孢方式及有性世代的型態等特性進行系列鑑定工作，結果發現菌有兩種無性世代，其一是Pesotum sp.，具孢柄束(synnemata)，由分生芽生方式(holoblastic)產孢，分生孢子橢圓形、單孢、無色透明，大小17-2.1*3.3-5.5um。至於本菌的有性世代，主要特徵世子囊殼黑色，球形(110-130um)，具有長啄(710-1625um)及孔口菌絲(ostiolar hyphae)，著生於植物組織表面；子囊孢子腎形或橢圓形，大小2.1-2.8*4.3-5.3um。本菌屬於異絲型，多種植物材料可誘使其產生子囊殼。本菌對Cycloheximide BLAST (NCBI)比對GenBank登錄之長啄殼菌菌株核酸序列，結果發現本菌與O.querci具有99%的相似度，而與O.piceae亦有98%的相似度。進一步，研究個菌株在麥芽抽出物培養基生長時，發現菌落形態出現同心輪紋，且均可在32°C的溫度生長。綜合上述諸特性，台灣廣葉杉萎凋病之病原菌建議歸於O.piceae complex之O.querci。
並列摘要
In the summer of 2002, a large area of the Chinese fir [Cunninghamia lanceolara (Lamb.) Hook. var. lanceolara] in central Taiwan appeared permanent wilting on the leaves of individual branches or of the entire tree. Many holes made by bark beetles (Crypturgus spp.) were observed in diseased tree trunks. Galleries existed in the dead Chinese fir trunk were similar to those made by the European elm bark beetles. The symptoms of Chinese fir wilt initially began with the leaves yellowing from the base of the branches then turned brown, and finall the entire tree died. Upon removal of the bark the sapwood of infected stem appeared discoloration or mottling. In cross section of the stem especially beneath the breeding galleries, the browning appeared as a broken or continuous circle in outer ring of the sapwood and irregular discolored zone in heartwood. Pesotum and Sporothrix species were consistently isolated from diseased tissues and bark beetles and in pathogenicity test they caused leaf yellowing and death of branches on 2-year-old Chinese fir. Perithecia of Ophiostoma sp. were also observed in the breeding galleries and sapwood adjacent to the gallerie. Perithecia superficial, black, base globose, 110-130 um in diameter. Neck straight, cylindrical, 710-1625 um long, ostiolar hyphae present. Ascospore 1-celledm hyaline, orange section shaped, without sheath, 2.1-2.8 x 4.3-5.3 um. Pesotum and Sporothrix anamorphs were produced. Pesotum sp., synnemata mostly erect, simple or branched near base, dark brown to black, conidia I-celled, hyaline, elliptical, 1.7-2.1 x 3.5-6.1 um, borne on blunt denticles; Sporothrix, conidiophores erect, simple or branched, conidia borne on short, prominent denticles at the tips, Or in whorls along the sides of conidiophores, conidia frequently in small clusters, becoming catenulate by acropetal formation of new conidia, chains often branched, I-celled, hyaline, variable in shape, ovoid to oblong, 1.8-2.5 x 3.3-5.5 um. The fungus was insensitive to cycloheximide and contained cellulose. According to the characters described above and its host, the pathogen was identified as a member of Ophiostoma piceae complex. Analysis of the ITS sequences revealed that the isolates showed 99% identity to O. qllerci (AFI98238, AF198239,AF211839, and AF211841, GenBank) and showed 98% identity to O. piceae (AF211843 and AF211845, GenBank). The isolates were able to grow at a maximal temperature up to 32°C. The colonies growing on malt extract agar plates not only developed concentric rings, but also produced fancy aroma. Based on the results, it was suggested that the pathogen is named as O. querd in Ophiostoma piceae complex.