國立臺灣大學植物病理與微生物學系暨研究所劉瑞芬2006-07-262018-06-292006-07-262018-06-291998http://ntur.lib.ntu.edu.tw//handle/246246/17657疫病菌Phytophthora parasitica Dastur (=Phytophthora nicotianae Breda de Haan) 是本省非常重要的植物病原菌。其屬於較 嗜高溫菌，在本省之分佈主要集中於中南 部，可危害之寄主種類繁多。研究顯示， 從不同寄主分離到之疫病菌在形態及生理 特徵上都有相當差異，接種試驗也發現菌 系間病原性有差別，寄主範圍也不同，可 能已有分化現象。本計畫之目的擬藉DNA 指紋分析來探討自不同寄主植物所分離到 之疫病菌菌株基因型的變異情形。為了尋 求適合的核酸探針，我們除了進行疫病菌 基因庫之篩選外，也嘗試探討以反轉錄轉 位子序列作為探針進行DNA 指紋分析的 可行性。目前的研究結果顯示，疫病菌確 實帶有Ty1-copia group 反轉錄轉位子序 列；以之為探針進行基因組南方雜合反應 時，供試菌株之雜合圖譜呈現明顯的多型 性。實驗結果也顯示，在一般培養條件下， 這一個轉位子不具有轉位能力。因此，其 在不同疫病菌分離株之存在情形或可反映 出這些菌株彼此之間的類緣關係。為了進 一步探討這一個核酸片段在疫病菌有性與 無性繁殖過程中的遺傳特性，我們另外還 進行了兩項分析，目前實驗仍在進行當 中，短期內應可獲得明確結果。Phytophthora parasitica Dastur (= Phytophthora nicotianae Breda de Haan), being able to attack a wide variety of plants, is a very notorious plant pathogen in the central and southern Taiwan. Crops of great economical importance such as citrus, tobacco, dieffenbachia, lily, cymbidium, etc., all are targets of this pathogen. It has been shown that there are variations in the morphology, pathogenicity, and virulence among P. parasitica isolated from different host species, indicating that differentiation may have arisen in P. parasitica isolated from different host species. The purpose of this study was to analyze the genotypes of P. parasitica by DNA fingerprinting. To search for probes appropriate for DNA fingerprinting analysis, 20 clones were randomly selected from the genomic library of P. parasitica . Subsequently, DIG-labeled probes were prepared from each clone and used in genomic Southern hybridization. Besides, the possibility that retrotransposon may serve as a genetic marker was also investigated at the same time. Fortuitously, results obtained from the latter approach have been very inspiring. It has been found that there indeed exist Ty1-copia retrotransposons in P. parasitica, as revealed by the presence of reverse transcriptase sequences. Analysis by genomic Southern hybridization using retrotransposon sequence as a probe indicated that polymorphisms exist among P. parasitica isolates tested. To determine its genetic stability, RNA was prepared from this fungus and analyzed by Northern hybridization as well as reversetranscriptase- polymerase chain reaction. No signal was detectable, indicating that this retroelement is unable to transpose. In addition, the genetic stability of this sequence throughout the asexual and sexual reproduction cycles of P. parasitica is now 3 being investigated as well.application/pdf33768 bytesapplication/pdfzh-TW國立臺灣大學植物病理與微生物學系暨研究所反轉錄轉位子疫病菌基因型DNA 指紋分析核酸探針Phytophthora parasitica DasturDNA fingerprintinggenotypesretrotransposonotherhttp://ntur.lib.ntu.edu.tw/bitstream/246246/17657/1/872313B002042.pdf