Modelling and manipulation of plant-aphid interactions: A new avenue for sustainable disease management of an important crop in Africa

在东非和中非，豆类是一种至关重要的作物，因为它们使土壤中含有固定氮(一种不可或缺的天然肥料)，进而支持玉米(玉米)和木薯等其他重要作物的种植。豆类是当地饮食中必不可少的一部分，因为它们含有丰富的蛋白质和至关重要的微量营养素，如铁和锌。由于豆类主要由妇女种植和交易，这种作物为妇女及其子女提供了额外的直接经济利益。不幸的是，许多病毒攻击豆类植物，造成严重的作物损失。虽然有一些豆类品种对其中一种病毒(称为菜豆普通花叶病毒)具有抗药性，但一种在非洲广泛存在且土生土长的密切相关病毒(菜豆普通坏死性花叶病毒)会导致这些抗病品系的植物死亡。因此，重要的是制定新的战略来保护这一至关重要的作物。我们的方法是攻击在植物之间传播这些病毒的昆虫(蚜虫)。我们发现，蚜虫与植物的相互作用在很大程度上是由植物的“小RNA途径”控制的。小RNA通路是最近发现的一种调节系统，被植物和许多其他生物用来控制自己基因的表达，以及抗击疾病。小RNA通路的发现给生物学和医学带来了革命性的变化。在植物中，小的RNA途径控制着自然信号化学物质的产生，这些化学物质可以吸引或击退包括蚜虫在内的害虫。有趣的是，病毒会产生一种被称为“沉默抑制物”的因子，来改变小的RNA途径。我们发现沉默抑制子影响了感染病毒的植物与蚜虫的相互作用，这种方式可能会提高这些昆虫获得病毒并将它们转移到其他植物的速度。我们在乌干达、肯尼亚和英国的两个中心组建了一个科学家团队，将这些发现从实验室转化到田间，并利用它们来保护豆类。然而，蚜虫及其传播的病毒是所有主要农作物的问题，这项工作将为更广泛的作物保护领域提供重要数据。我们的跨国团队将合作：a.确定在植物中调节植物-蚜虫交流的潜在因素：小RNA，它们控制的基因，以及它们调节其产生的化学信号。B.使用数学流行病学学科提供的建模方法来帮助我们设计实验(在实验室和后来的田间条件下)，以预测如何利用改变植物的吸引力(无论是由于植物的变化还是作为陷阱或诱饵的信号化学物质的部署)来帮助最小化或防止病毒的传播。C.利用1和2中的工作设计实验，以测试在受控和模拟的田间条件下改变植物对蚜虫的反应或利用纯化的信号化学品诱捕或威慑蚜虫对病毒传播的影响。D.通过泛非豆类研究联盟向非洲作物科学家、种植者和消费者传播我们的工作所获得的信息，泛非豆类研究联盟是28个非洲国家的国家豆类研究方案的网络。

In Eastern and Central Africa beans are a vital crop because they enrich the soil with fixed nitrogen (an indispensable natural fertilizer), which in turn supports the cultivation of other important crops such as corn (maize) and cassava. Beans are an essential part of the regional diet because they are rich in protein and crucially important micronutrients like iron and zinc. Since beans are predominantly grown and traded by women, this crop provides additional direct economic benefits to women and their children. Unfortunately, a number of viruses attack bean plants, causing severe crop losses from disease. Although there are a few bean varieties with resistance to one of these viruses (called bean common mosaic virus), a closely related virus that occurs widely in, and is indigenous to, Africa (bean common necrotic mosaic virus) causes plants of these 'resistant' lines to die. Thus, it is important to develop new strategies to defend this vital crop. Our approach is to attack the insects (aphids) that transmit these viruses from plant to plant. We have found that aphid-plant interactions are controlled in large part by the plant's 'small RNA pathways'. Small RNA pathways are a recently discovered regulatory system used by plants and many other organisms to control the expression of their own genes as well as to fight off disease. The discovery of small RNA pathways has revolutionized biology and medicine. In plants, small RNA pathways control, among other things, the production of natural signal chemicals that attract or repel insect pests, including aphids. Intriguingly, viruses produce factors called 'silencing suppressors' that modify small RNA pathways. We have found that silencing suppressors affect the interactions of virus-infected plants with aphids in a way that is likely to enhance the rate at which these insects acquire viruses and transport them to other plants. We have assembled a team of scientists based in Uganda, Kenya and at two centres in the UK to translate these findings from the laboratory to the field and exploit them for protection of beans. However, aphids and the viruses they transmit are problems for all major crops and the work will yield vital data for the wider field of crop protection. Our multinational team will collaborate to: A. Identify potential factors involved in mediating plant-aphid communication in plants: small RNAs, the genes they control, and the chemical signals whose production they regulate. B. Use the modelling methods provided by the discipline of mathematical epidemiology to help us design experiments (under lab and later field conditions) to predict how altering the attractiveness of plants (whether engendered by changes in the plant or deployment of signal chemicals as traps or decoys) could be used to help minimize or prevent the transmission of viruses. C. Utilize the work from 1 and 2 to design experiments to test the effects on virus transmission of modifying plant responses to aphids or utilization of purified signal chemicals to trap or deter aphids under controlled and simulated field conditions.D. To achieve impact by disseminating information gained from our work to African crop scientists, growers and consumers through the Pan-Africa Bean Research Alliance, a network of the national bean research programmes of 28 African nations.