放線菌＂Lentzea albidia＂ SR-A5菌株的分離鑑定與防除花卉病毒之研究

本研究由龍葵植物根圈分離出一種放線菌屬之分離株SR-A5，其培養於大豆培養基之發酵液，於Indirect ELISA及奎藜接種試驗中顯示具有可分解多種植物病毒及降低病毒感染力之效果，作用對象包括蕙蘭嵌紋病毒Cymbidium mosaic virus （CymMV）、齒舌蘭輪斑病毒Odontoglossum ringspot virus （ORSV）、胡瓜嵌紋病毒Cucumber mosaic virus （CMV）及車前草嵌紋病毒Plantago asiatica mosaic virus （PlAMV）。SR-A5分離株經由生理生化特性分析及16S rDNA核酸序列定序結果鑑定為Lentzea albida。SR-A5粗發酵液經無菌水稀釋8-16倍時，仍具有分解CymMV、ORSV、CMV及PlAMV等病毒之效果，但其有效稀釋倍數則視所施病毒對象而定。SR-A5發酵液為熱敏感性，使用時須在低於其敏感溫度的條件下才能發揮具體的作用。西方墨點法分析顯示SR-A5發酵液可分解CymMV、ORSV、CMV及PlAMV等四種受測植物病毒之鞘蛋白，具有蛋白分解酶之活性。SR-A5發酵液對刀片表面受污染之病毒可達到明顯的防除效果，可於5 min內分解CymMV及ORSV;於5 min後可分解CMV及10 min後可分解PlAMV。本研究為首次證實屬於放線菌Lentzea albida之SR-A5菌株，其發酵液具有對CymMV、ORSV、CMV及PlAMV等多種植物病毒之分解能力與降低病毒感染力之作用，具有應用於抑制植物病毒活性之潛力，尤其是表面受病毒汙染之刀具。

"An actinomyces isolate (denoted as SR-A5) was collected from plant rhizosphere of Solanum nigrum L. By indirect ELISA and inoculation to Chenopodium quinoa, SRA5 possessed the ability to lyse the coat proteins of Cymbidium mosaic virus (CymMV), Odontoglossum ringspot virus (ORSV), Cucumber mosaic virus (CMV) and Plantago asiatica mosaic virus (PlAMV), and to reduce their infectivities on C. quinoa. SR-A5 was identified as an isolate of Lentzea albida according to biochemical characterization and the nucleotide sequence of 16S rDNA. The 8-16x dilutions of SR-A5 metabolites could degrade CymMV, ORSV, CMV and PlAMV. However, the effective working dilution of SR-A5 metabolites was dependent on the virus species. The SR-A5 metabolites is heat sensitive. The function of degrading viruses kept effective only under the condition that temperature was lower than the limited degree of heat sensitivity. Results of western blots demonstrated that SR-A5 metabolites possessed the protease activity to degrade viral coat proteins of CymMV, ORSV, CMV and PlAMV, respectively. When the virus-contaminated blades was treated with SR-A5 metabolites, it spent less than 5 min to eliminate CymMV or ORSV, 5 min later for CMV, and 10 min later for PlAMV. Lentzea albida is first reported to degrade coat proteins of CymMV, ORSV, CMV and PlAMV, and have the potential to prevent virus infection. Results in this study revealed that application of L. albidia SR-A5 metabolites by the way of surface treatment can effectively eliminate the surface contamination of plant viruses."