超低溫冷凍去病毒技術在臺灣幾種重要無性繁殖作物健康種苗產業上之應用評估

Evaluation of cryotherapy for its industrial application in virus elimination of several important vegetative propagation crops in Taiwan

"超低溫冷凍技術主要應用於種原保存，去病毒為附加效果。目前去病毒技術主流仍為生長點組織培養，但在不易得到無病毒生長點培植體且已建立超低溫冷凍保存系統的作物，可評估使用超低溫冷凍去病毒技術（冷療處理）之可行性。比較生長點組織培養與超低溫冷凍技術對去除病毒的效果，過去的研究案例顯示，以生長點培養的再生率較高，惟去病毒率則以超低溫冷凍處理較高，不同品種間之再生率與去病毒率差異極大。本報告嘗試以經濟效益評估蝴蝶蘭、文心蘭、百香果、紅龍果、馬鈴薯、甘藷、草莓、柑橘及綠竹等9種作物應用超低溫冷凍技術去除病毒的可行性。其中草莓及柑桔已有應用超低溫冷凍技術之報告，在有新病毒發生且無法以生長點組織培養去病毒之情況下，建議可嘗試超低溫冷凍去病毒技術之開發應用；蘭花種類繁多，目前農政單位並無提供健康種苗，業者通常以確認無病毒之植株進行分生苗繁殖，農業試驗所（農試所）亦利用擬原球體（Protocorm-Like Body, PLB）加上薄層培養技術建立蝴蝶蘭去病毒技術；馬鈴薯及甘藷生長點培養去病毒效率較超低溫冷凍技術高；百香果、紅龍果及綠竹則尚未建立超低溫冷凍相關技術。總結評估推論目前蝴蝶蘭、文心蘭、百香果、紅龍果、馬鈴薯、甘藷及綠竹等7種作物在臺灣較無發展超低溫冷凍技術去除病毒之急迫性與必要性。"

"Cryopreservation is a technique commonly used to preserve plant tissues in liquid nitrogen. This method is one of the most important tools to preserve germplasms. When shoot tips are used as explants, cryopreservation may have extra functions in virus elimination. This phenomenon is known as cryotherapy. Studies have shown that using shoot-tip or meristem culture could improve the efficacy of regeneration but fails to completely eliminate viruses occasionally. Cryotherapy could greatly improve the efficiency of virus elimination in some crops. Plant cells in the top layers of apical dome and primordia of two youngest leaves are able to survive after cryotherapy. However, the regeneration rate and virus elimination vary considerably even among different varieties of the same crop. This report evaluates the economic feasibility of cryotherapy applying to eliminate viruses in nine vegetatively propagated crops including Phalaenopsis, Oncidium, passion fruit, pitaya, potato, sweet potato, strawberry, citrus and bamboo in Taiwan. Cryopreservation has been reported in strawberry and citrus. To deal with newly invasive viruses which can’t be eliminated by meristem culture, cryotherapy would be a better alternative. Unlike strawberry and citrus, cryotherapy may not be economically practical in potato and sweet potato because viruses in these two crops can be effectively removed by meristem culture. Cryopreservation has never been developed for passion fruit, pitaya and bamboo and it remains unclear whether or not the method will be effective to eliminate viruses in these three crops. There is an urgent need to eliminate viruses using cryotherapy in orchids. When orchid plants are infected by viruses, meristem culture coupling with chemotherapy and/or thermotherapy is often used to generate virus-free plants. In addition, researchers in the Taiwan Agricultural Research Institute have recently developed a new technique using thin sections from protocorm-like body (PLB) and ribavirin treatment to eliminate viruses in Phalaenopsis and Oncidium. Through our assessments, we conclude that there is no urgent need to develop cryotherapy to eliminate viruses in Phalaenopsis, Oncidium, potato, sweet potato, passion fruit, pitaya and bamboo in Taiwan."