夜來香病毒之研究與檢定技術發展現況
Other Title
Current status of tuberose virus research and the development of its indexing techniques.
Journal
植物病理學會刊
Journal Volume
8
Journal Issue
3
Pages
89-94
Date Issued
1999-09
Author(s)
Abstract
夜來香，又名晚香玉，雖原產於墨西哥，但頗能適應台灣之風土氣候，被視為具發展潛力之近本土化球根花卉。文獻上有關夜來香病毒病之記載甚少，過去僅紐西蘭曾報導有馬鈴薯Y屬病毒感染之情形，但並未鑑定出確實之病毒種類。本研究室於1994年自夜來香植株中分離出一種長絲狀病毒，經鑑定後證實為一Potyvirus屬之新紀錄病毒。調查發現本省絕大多數無性繁殖之重瓣品系夜來香均已感染此病毒，由於病株之葉片及花軸上會出現輕微嵌紋病徵，因此將其命名為夜來香微嵌紋病毒(Tuberose mild mosaic potyvirus, 簡稱TMMV)。TMMV除感染夜來香外並未發現有其他寄主植物。除機械傷口接觸外其亦可經由蚜蟲以非永續型方式傳播。以電泳分析估計TMMV之鞘蛋白分子量約為38 kDa。血清試驗結果發現TMMV與其他22種已知之potyviruses均不具同源之血緣關係，顯示TMMV應為一具獨立分類地位之Potyvirus屬病毒。此項結論後經進一步選殖及定序TMMV RNA之3'端約2kb核酸序列並與其他已知之16種potyviruses之核酸與氨基酸序列比對後更加確定。所製備之TMMV抗血清可以應用於ELISA、direct tissue blotting (DTB)及SDS- immunodiffusion test等三種方法將TMMV由感病植物組織中專一性檢出。但檢定對象如果是生長中之植株時三者中以ELISA最為適用，若對象為儲藏球根時則以DTB最佳，而SDS- immunodiffusion test則較適用於病毒種類之確認。由於發現TMMV在夜來香植株全身部位之濃度分佈頗不均勻，其中以幼嫩新葉及花軸鞘葉之病毒濃度較高，故可作為檢定時之最佳採樣部位，而檢定儲藏期球根時則應以鱗葉為取樣標的，其病毒檢出率之準確度最高。試驗中更發現利用25℃回溫處理長期冷藏於5℃之種球，可促使病毒濃度於二天內迅速提升，增加病毒檢定之正確性。
Tuberose (Polianthes tuberosa L.), a species native to Mexico, has been cultivated in Taiwan for over 300 years and has become an economically important bulb crop. Several diseases including Erwiniaspp., Botrytis spp., and S c l e rotium rolfsii have been documented to infect tuberoses, however, there has not been any report on virus disease until 1988 when a virus, possibly a potyvirus, was described in New Zealand. During a survey for ornamental plant virus diseases in 1994, foliar mild mosaic symptoms were noticed on most tuberose plants in Taiwan. A virus was isolated from infected plants and it was subsequently identified as an newly recognized potyvirus, designated as tuberose mild mosaic potyvirus (TMMV), based on particle morphology, aphid transmissibility and the cylindrical inclusions it induced in infected cells. Tuberose was the only host identified so far for TMMV in our inoculation experiment. The purified capsid contained a single species of protein monomer with an estimated relative mass of 38 kDa. Based on the result of several serological tests, TMMV was found serologically distinct to other 22 known potyviruses tested. This was further confirmed by the comparative sequencing studies of a 2 kb DNA fragment cloned from the 3' terminus of TMMV's RNA. Using the antiserum prepared against purified TMMV virions, we showed that ELISA, tissue blotting and SDS-immunodiffusion test could specifically detect the virus from tuberose tissue. Among them, ELISA was found the most appropriate one for detecting virus infection in leaf tissue, however, tissue blotting was evaluated as the best choice for bulb indexing. TMMV was found distributed unevenly in different parts of tuberose plants. The highest concentration was detected in sheath leaves of flower stems followed by the young leaves; they were reasonably taken as the best sampling sites during field survey. To index tuberose bulbs, however, lateral buds and apex scale leaves were optimum choices for sampling. It was also found that by treating the 4℃-stored bulbs at 25℃ for 2 days could enhance virus multiplication in bulb tissue from a minimum to a detectable level thus allowing better and consistent indexing. An antiserum against bacteria expressed cloned TMMV coat protein has been successfully produced and shown that it was applicable, equivalent to the antibodies produced by traditional means, in the detection of TMMV in tuberoses.
Publisher
中華民國植物病理學會
Type
journal article