The potential of gene-knockdown for controlling varroa mites

蜜蜂通过为野生和养殖植物的花朵授粉对人类非常重要。据估计，我们吃的第三口食物在某种程度上依赖于蜜蜂。在中国的一个地区，由于意外地过度使用杀虫剂，杀死了所有的蜜蜂和其他授粉昆虫，那年的苹果树不得不人工授粉。考虑到英国较高的工资水平，这种情况将使苹果成为绝对的奢侈品。不幸的是，蜜蜂的数量每年都在严重下降，欧洲和美国的蜜蜂每年损失超过30%-这是不可持续的。蜜蜂数量下降的确切原因尚不清楚，但可能是由于几个因素。其中一个最重要的因素是寄生螨狄斯瓦螨（Varroa destructor），它从蜜蜂身上吸血并传播严重的病毒性疾病。使用杀虫剂控制瓦螨变得越来越不有效，因为瓦螨已经对少数可用的杀虫剂产生了抗药性。开发杀死瓦螨但不伤害蜜蜂的杀虫剂非常困难，因为它们彼此关系相对密切，不像开发杀虫剂杀死猫身上的跳蚤或猪身上的绦虫。目前迫切需要开发一种瓦螨属特异性的、环境友好的杀虫剂或克服瓦螨属对注册杀虫剂的抗性机制的方法。我们最近开发了一种敲除瓦螨属个体和特定基因的方法，该方法不会影响蜜蜂或任何其他动物。在这个项目中，我们的目标是构建双链RNA（dsRNA）片段，有效地杀死螨，但不影响蜜蜂。通过搜索所有瓦螨属基因的大型数据库，将确定可以有效和安全靶向的基因片段。这些dsRNA构建体将喂给幼虫和成年蜜蜂，以评估它们在开始蜂巢处理之前作为概念验证的有效性。此外，我们还将鉴定与对特定杀虫剂的抗性有关的基因，并研究当我们敲除这些基因时，抗性螨是否会对杀虫剂敏感

Honey bees are incredibly important to humans through their pollination of flowers of both wild and farmed plants. It is estimated that very third mouthful of food we eat is reliant to some extent on honey bees. When there was an accidental overuse of insecticides in an area of China that killed all the bees and other pollinating insects, the apple trees had to be hand pollinated that year. Taking into account higher wages in the UK, such a scenario here would make apples an absolute luxury item. Unfortunately, honey bee numbers are seriously declining year on year with areas in Europe and the USA suffering bee losses over 30% every year – this is not sustainable. The exact reasons for honey bee declines are not known for certain, but are likely due to several factors. One of the most important factors is the parasitic mite Varroa destructor that sucks the blood from bees and transmits serious viral diseases.Control of Varroa using insecticides is becoming less effective as the Varroa have become resistant to the handful of available insecticides. Developing insecticides that kill Varroa but leave the bee unharmed is very difficult as they are relatively closely related to each other, unlike the scenarios of developing pesticides to kill fleas on cats or tapeworms in pigs. There is an urgent need to develop a Varroa-specific, environmentally friendly insecticide or some method of overcoming the Varroa’s resistance mechanism to the registered insecticide.We have recently developed a method to knockdown individual and specific genes in the Varroa that will not affect honey bees or, indeed any other animals. In this project we aim to construct pieces of double-stranded RNA (dsRNA) that effectively kill the mite, but do not affect the bees. By scouring large databases of all the Varroa genes will identify pieces of genes that can be effectively and safely targeted. These dsRNA constructs will be fed to larval and adult bees to assess their effectiveness as a proof-of-concept before embarking on hive treatments. Additionally, we will identify the genes involved in resistance to a specific insecticide and investigate whether resistant mites become susceptible to the insecticide when we have knocked down these genes