The potential to control insects and other organisms antagonistic to wheat by the up regulation of hydroxamic acids.

小麦是英国一种重要的农作物。绿蝇通过直接取食和向作物传播疾病，降低了粮食品质和产量，需要加以控制。人们试图通过转基因将杀虫活性物质从其他生物转移到小麦中，从而减少杀虫剂的使用。然而，许多植物物种可以通过产生少量的天然化学物质来防御入侵的害虫。我们计划利用这一特性，为谷类作物开发替代的、更环保的抗虫害策略。具体地说，我们对异羟肟酸(HAS)感兴趣，这是一种在小麦和其他谷物中产生的化合物，可以保护植物免受害虫的侵害。这些化学物质减少了蚜虫的发育，并可能阻止其他昆虫和杂草。HAS控制谷类害虫的潜力已被深入研究，植物体内HAS生物合成的途径现已为人所知。我们计划在对病虫害具有不同程度抗性的小麦品种中检测HA的产生，以证实这些化合物确实在抗蚜虫方面具有重要作用。通过这种方式，我们希望开发出仅在必要时才启动植物天然防御化合物生产的方法，从而节省植物的能量并减少对害虫的抗性发展。这将涉及到育种技术，将高产的哈斯德引入可以在英国生长的小麦植株。然而，全面的人类风险评估将是该项目之后所做工作的一部分。

Wheat is an important agricultural crop in the United Kingdom. Greenfly (aphids) can reduce grain quality and yield by direct feeding and transmission of diseases to this crop and they need to be controlled. The Department of the Environment, Food and Rural Affairs and the agricultural industry have invested much effort into controlling these pests and others, including fungi and weeds, with pesticides, but there is concern that excessive use of such agents could harm the environment and pass into the human food chain. Attempts have been made to reduce pesticide use by transferring insecticidally active agents into wheat from other organisms by genetic modification. However, many plants species can mount their own defence by producing small amounts of natural chemicals that can deter invading pests. We plan to exploit this property to develop alternative, more environmentally compatible pest resistance strategies for cereal crop plants. Specifically, we are interested in the hydroxamic acids (HAs), a family of compounds produced in wheat and other cereals that defend plants against pests. These chemicals reduce the development of aphids and may deter other insects and weeds. The potential of HAs to control pests in cereals has been intensively studied and, the pathway involved in their biosynthesis within the plant is now known. We plan to examine HA production in wheat varieties that have varying degrees of resistance to pests and disease to confirm that these compounds do indeed have a significant role in aphid resistance. Besides differences in HA levels in these varieties that can be detected under normal conditions, we will exploit ways of increasing production in the wheat by investigating the action of other natural plant chemicals, called plant activators, which can cause increased production in the defence chemistry of plants. In this way we hope to develop means to switch on the production of the plant's natural defence compounds only when necessary, thereby conserving the plant's energy and reducing the development of pest resistance. In addition to demonstrating the effect of high levels of HAs on aphids, we will also investigate their effects on other insects such as gout fly, and to weeds such as black-grass. We know the genetic backgrounds, or pedigrees, of the varieties that we have chosen to study, so we will be able to identify the original parents of wheat varieties that produce high levels of HAs or that are capable of increasing production by the action of the plant activators. Therefore, by the end of the project, working under more practically oriented funding programmes, we will develop our findings together with industrial partners to produce new varieties of wheat that will be able to protect themselves more effectively in the face of a pest attack. This will involve breeding techniques to introduce high production of HAs into wheat plants that can grow in the United Kingdom. The HAs are naturally produced in the roots and green tissue of the plant and so do not influence the nutritional value of the seed from which we make flour for food production, but we will ensure that high HA producing varieties do not show detectable amounts of HAs in the grain. However, full human risk assessment would be part of the work done following this project. Although we can only speculate on how valuable increased HA production will be in developing new means for controlling pests on wheat, we know that HAs are antagonistic to a range of pests, weeds and fungal pathogens. We have established chemical analytical and molecular biological methods for analysing the natural chemicals and associated genes involved in the production of these materials and we have, in preliminary studies, demonstrated increased production of HAs with the natural plant activator chemical, cis-jasmone.