台灣地區葉芽線蟲Aphelenchoides besseyi族群之種內變異

The Intraspecific Variation of Aphelenchoides besseyi Populations in Taiwan

曾巧燕(C. Y. Tzeng) ； 林奕耀(Y. Y. Lin)

《植物病理學會刊》 14卷1期 (2005/03) Pp. 67-75

https://doi.org/10.6649/PPB.200503_14(1).0008

摘要

分別測量由烏日、大湖、嘉義分離之水稻葉芽線蟲(Ar)、草莓葉芽線蟲(As)、山蘇花葉芽線蟲(Af)及中興大學植病系線蟲室保存之水稻葉芽線蟲(Ab)，經形態鑑定皆為Aphelenchoides besseyi。另以掃描式電子顯微鏡觀察線蟲體表細微構造顯示四者間無差異。對山蘇花、草莓、水稻及秋石斛等之病原性測試結果顯示，四者皆可感染草莓與水稻，僅Af對山蘇花具病原性，As則無法感染秋石斛。交叉交配試驗的結果為各處理皆有子代產生，且子代仍然具有繁殖產生後代的能力。子代與親代之形態無差異，且各子代對草莓均有病原性，僅有Afs、Afb及Afr（以Af為雄性父本雜交產生之子代）對山蘇花有病原性。除Afr及Arf之外，其他子代中皆無雄蟲存在。本研究發現，將Ab和As培養在Alternaria citri後，兩者均產生孤雌生殖現象，與Huang氏等報告之A. besseyi只行兩性生殖迥異。由隨機增幅核酸多型性分析(random amplified polymorphic DNA, RAPD)的結果可看出，利用隨機引子S4、S7與S8增幅出之片段，Af與As、Ar、Ab差異大，As和Ab差異小。以共同引子對18S/26S增幅葉芽線蟲之核糖體核酸內轉錄區間(internal transcribed spacer, ITS)，可得一大小約l,000 bps的增幅產物，經酵素Rsa I剪切後，Af可得一大小約l,000 bps的片段，As與Ab為約700 bps的片段，Ar為約800 bps的片段。由本研究結果可知，台灣地區之葉芽線蟲A. besseyi族群於生理特性、病原性及分子序列上確實存在變異情形，但此變異與寄主或來源地區之相關性仍有待進一步探討。

關鍵字

葉芽線蟲 ； Aphelenchoides besseyi ； 種內變異

並列摘要

The morphological and morphometric data of four populations of Aphelenchoides besseyi, including two populations isolated from rice plant (Ar and Ab) and one from strawberry (As) and fern (Af) respectively, were not different. All of them infested strawberry and rice, but only ”Af” attacked fern. ”As” could not infect bailey. Crossing hybrid test showed offsprings in every combination treatment, and they were reproducible. The morphology and morphometrics of parental generations and its offsprings had no significant differences. All offsprings could infect strawberry, but only Afs, Afb, and Afr could infect fern. Besides Afr and Arf, the males of Afs, Afb and Ars could not be found. Parthenogenesis was observed on As and Ab that cultivated on PDA slant with Alternaria citri. Random amplified polymorphic DNA data showed that the amplification fragments of Ar, Ab, As and Af were different, but the fragments of As and Ab were alike. Using 18S and 26S universal primers to amplify ribosomal DNA, all populations yield a product about 1,000 bps. Amplified rDNA fragments digested with restriction enzyme Rsa I, Af resulted a band uncut; As and Ab were digested into 700 bps and Ar was 800 bps, both with a minor band that had a size indistinguishable from A. citri products. Therefore, the physiology, host range and rDNA sequence of rice, strawberry, and fern foliar nematodes were variant in Taiwan.

並列關鍵字

foliar nematode ； Aphelenchoides besseyi ； intraspecific variation