抗木瓜輪點病毒基因改造木瓜果實之安全性評估   全文下載

Food Safety Evaluation of Papaya Fruits Resistant to Papaya Ring Spot Virus

基因改造木瓜為將木瓜輪點病毒鞘蛋白基因成功轉入植株使其具有抗病毒感染能力。然而，基因改造食品之食用安全性仍有爭議。本研究利用基因毒理及動物毒理試驗方法評估2種基因改造木瓜品系16-0-1及 18-2-4果實，並比較與非基因改造母本植株台農2號（TN-2）果實之差異性。首先，新鮮木瓜果肉經冷凍乾燥後，進行三種基因毒性測試：Ames分析（沙門菌TA98、100、102、1535及TA1537）、中國倉鼠細胞染色體變異分析（活體外）及小鼠周邊血液微核分析（活體內）。試驗結果顯示，非基因改造及2種基因改造木瓜果肉均不具基因毒性。以胃管針經口餵食5 g/kg body weight果肉進行大鼠口服急毒性試驗，結果亦無急性毒性。以胃管針經口餵食1 g/kg body weight果肉連續28天，結果顯示，非基因改造及2種基因改造木瓜對大鼠體重、飼料消耗量、血液及血清生化值、臟器重及病理學檢查均無不良毒性作用，試驗組間亦無明顯差異。綜合以上結果，抗木瓜輪點病毒基因改造與非基因改造木瓜果實兩者之安全性為實質等同安全。

Genetically modified (GM) papaya plant resistant to infection by Papaya Ring Spot Virus (PRSV) was successfully generated by cloning the coat protein (CP) gene of the PRSV. However, the food safety of GM foods remains controversial. This study assesses the food safety of two GM papayas, 16-0-1 and 18-2-4, and compares them with that of non-GM papaya, Tainung-2 (TN-2), using genetic and animal toxicity assays. Pulps of fresh papaya fruits were lyophilized and grounded before use. Three genotoxicity assays were performed: the Ames test of Salmonella typhimurium tester strains (TA98, TA100, TA102, TA1535 and TA1537); the chromosomal aberration of Chinese hamster ovary (CHO-K1) cells (in vitro); and micronucleus assays for mice (in vivo). Experimental results demonstrated that both non-GM and GM papaya fruits had no genotoxicity. Acute oral toxicity and 28-day repeated feeding toxicity tests for these papayas were performed via the oral gavage method for rats. All GM papaya fruit had no acute toxicity at a maximal dose of 5 g/kg body weight. Furthermore, the results of the 28-day study at 1 g/kg body weight in rats revealed no adverse-related effect in the body weight, feed consumption, hematology, blood biochemical parameters, organ weights and pathology in both GMs and non-GM papaya groups. In conclusion, PRSV-resistant papaya fruit lines 16-0-1 and 18-2-4 are comparable to their parent non-GM (TN-2) counterparts and are equivalent in food safety.