台灣產黑色線齒菌(Grammothele fuligo (Berk. & Br.) Ryv.)性別與種內分化之研究

Abstract

黑色線齒菌(Grammothele fuligo (Berk. & Br.) Ryv.)，為一種寄生於單子葉植物之熱帶擔子菌，子實體具有孔洞，但其子實層卻只分佈在孔洞的底部，而非與孔洞平行的孔壁，為台灣棕櫚植物上常見之寄生菌。 本論文採集台灣本島包括：臺北市、桃園縣中壢市、嘉義市、宜蘭縣貢寮鄉、臺北縣淡水鎮六個地點之樣本，以及離島龜山島上寄生於蒲葵（Livistona chinensis (Jacq.) R. Brown var. subglobosa (Hassk.)）原始林之樣本，分別對雙核與單孢菌株做形態鑑定、培養基鑑定研究（cultural study）、交配試驗，以及ITS1-5.8S-ITS2 rDNA序列之比較。 結果發現，各樣本間之子實體（擔子果）形態、培養基生長特性、ITS1-5.8S-ITS2 rDNA序列等，都無太大差異。同樣本間之雙核菌株與單孢菌株在培養基上特性大致相同，惟同一樣本中之雙核菌株生長速率較單核菌株快。 在性別研究上，黑色線齒菌之交配系統為四極型，七個樣本中已有生物種（biological species）之分化，可分為兩個不孕群（intersterile groups, IGs），其中共發現有10種A因數及13種B因數，各因數之分佈與地理無絕對關係。故推論台灣各地之黑色線齒菌親緣關係十分相近，但已有分化之趨勢。

Grammothele fuligo (Berk. & Br.) Ryv. is a special polypore classified currently in Grammotheleaceae, Poriales, Basidiomycetes, Basidiomycota, which is only seen on monocotyledons in tropical area and common on palm trees in Taiwan. The basidioma is resupinate on the host and with shallow pore on the surface. Unlike typical polypores, the hymenium is restricted to the bottom of the tubes while the tube walls are sterile. During the field survey, seven samples of G. fuligo were collected from different locations in Taiwan viz., Taipei, Chunli, Chiayi, Kungliao, Tanshui, and Kuishan islet. Kuishan islet is an off coast island of Ilan county, a north eastern prefecture of Taiwan, where Livistona chinensis (Jacq.) R. Brown var. subglobosa (Hassk.), a common host of G. fuligo in Taiwan are inhabiting as a natural forest. As the results of present investigation, there are no apparent morphological differences between 7 samples. They also show similar cultural characteristics and ITS1-5.8S-ITS2 rDNA sequences. Within the same sample, no differences was observed from cultural study between dikaryotic strain (DS) and single-spore strains (SSs), but the growth rate of DS are higher than SSs. In sexuality study, the mating system of G. fuligo is tetrapolarity. There exist 2 intersterile groups (IGs) in 7 samples, and 10 A and 13 B mating factors. The distribution of all these mating factors in Taiwan indicated that there are no direct relationship with the locations. It is concluded that G. fuligo from different habitats in Taiwan are genetically very homologous and phyllogenetically very close, but in the process of speciation.