抗盲蝽转基因棉花的研发

盲蝽属半翅目昆虫，是危害棉花的主要害虫。此外，由于其刺吸式的取食方式，Bt蛋白对其毫无毒杀作用。在Bt转基因棉花种植面积逐步扩大的今天，防治盲蝽类害虫，培育新型的抗虫棉将是未来棉花育种的重要目标。最近，华中农业大学张献龙团队的科研人员利用RNAi干涉技术成功实现了对中黑盲椿的防治。

研究人员从中黑盲椿（Adelphocoris suturalis）中克隆了一个与生殖有关的基因，该基因编码脂肪酸乙酰辅酶A还原酶（FATTY ACYL-COA REDUCTASE, AsFAR），主要在昆虫信息素生物合成途径中发挥作用。该基因的表达受到抑制后，昆虫信息素合成受阻，卵巢发育异常。研究人员构建了针对AsFAR基因的dsRNA，并将其转化到棉花中。经鉴定，转基因棉花表现出很强的中黑盲椿抗性效果。
RNAi干涉技术不仅是研究基因功能的重要工具，它也正在成为作物保护领域的有力武器。近日，美国环保署（US EPA）正式批准了第一个基于RNA干扰技术的杀虫剂。孟山都利用RNAi技术开发了能够干涉昆虫DvSnf7基因从而达到玉米根甲虫防治效果的转基因玉米MON87411，并继续应用杂交聚合的方法得到升级版SmartStax  PRO玉米（比SmartStax多了dsDvSnf7基因）。其中MON87411已于2015年获得了美国和加拿大的种植许可。RNAi干涉技术的成功应用将成为Bt蛋白的有力补充，解决稻飞虱、玉米蚜、小麦蚜虫、棉花盲蝽等害虫的为害问题。

New Phytologist, 30 June 2017
A transgenic strategy for controlling plant bugs (Adelphocoris suturalis) through expression of double-stranded RNA homologous to fatty acyl-coenzyme A reductase in cotton
Authors
Jing Luo, Sijia Liang, Jianying Li……Lizhen Chen, Shuangxia Jin, Xianlong Zhang*
*: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, China
Summary
Plant bugs (Miridae species), which are sap-sucking insects, have emerged as major pests of cotton in China. Most Miridae species are not sensitive to commercial Bacillus thuringiensis (Bt) cotton, resulting in significant economic losses and an increased application of insecticide, which eventually may compromise the future of Bt cotton.
We demonstrate that FATTY ACYL-COA REDUCTASE (AsFAR) plays an essential role in the reproduction of the bug Adelphocoris suturalis. Down-regulation of AsFAR expression by injection of double-stranded RNA suppresses ovarian development and female fertility, resulting in females producing few viable offspring.
To determine the viability of an RNA interference approach to limit FAR expression and reproductive ability in A. suturalis, a dsRNA targeting the AsFAR gene (dsAsFAR) of A. suturalis was expressed in transgenic cotton plants. AsFAR transcription levels were significantly downregulated in A. suturalis feeding on the transgenic plants. In contained field trials, the transgenic cotton lines significantly suppressed the development of A. suturalis populations and were resistant to damage caused by plant bug infestation.
These results suggest a new strategy for the management of plant bug pests of cotton.

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