Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, 4001, Queensland, Australia.
Sugar Research Australia, Indooroopilly, 4068, Queensland, Australia.
Nat Commun. 2017 Nov 14;8(1):1496. doi: 10.1038/s41467-017-01670-6.
Banana (Musa spp.) is a staple food for more than 400 million people. Over 40% of world production and virtually all the export trade is based on Cavendish banana. However, Cavendish banana is under threat from a virulent fungus, Fusarium oxysporum f. sp. cubense tropical race 4 (TR4) for which no acceptable resistant replacement has been identified. Here we report the identification of transgenic Cavendish with resistance to TR4. In our 3-year field trial, two lines of transgenic Cavendish, one transformed with RGA2, a gene isolated from a TR4-resistant diploid banana, and the other with a nematode-derived gene, Ced9, remain disease free. Transgene expression in the RGA2 lines is strongly correlated with resistance. Endogenous RGA2 homologs are also present in Cavendish but are expressed tenfold lower than that in our most resistant transgenic line. The expression of these homologs can potentially be elevated through gene editing, to provide non-transgenic resistance.
香蕉（Musa spp.）是 4 亿多人的主食。超过 40%的世界产量和几乎所有的出口贸易都基于卡文迪什香蕉。然而，卡文迪什香蕉正受到一种强毒真菌——尖孢镰刀菌古巴专化型 4 号（Fusarium oxysporum f. sp. cubense tropical race 4，TR4）的威胁，目前还没有发现可接受的抗性替代品种。在这里，我们报告了对 TR4 具有抗性的转基因卡文迪什香蕉的鉴定。在我们为期 3 年的田间试验中，两种转基因卡文迪什香蕉品系，一种转染了 RGA2 基因（一种从 TR4 抗性二倍体香蕉中分离出来的基因），另一种转染了源自线虫的 Ced9 基因，保持无病状态。RGA2 基因在转基因系中的表达与抗性呈强相关性。RGA2 的内源性同源物也存在于卡文迪什香蕉中，但表达水平比我们最具抗性的转基因系低 10 倍。通过基因编辑，这些同源物的表达水平可能会提高，从而提供非转基因抗性。
