Increased pest resistance in oilseed rape mediated by an enhanced UV-B response

Attack by insects, molluscs and microbial pathogens causes significant losses to the oilseed rape crop and considerable expense is incurred in trying to counter this problem by using pesticides. The aim of this project is to undertake research to underpin the development of new oilseed rape varieties with increased resistance to insect herbivory. Exposure of plants to UV-B wavelengths, which are a natural component of sunlight, has been shown to reduce the attractiveness of plants to insect herbivores by altering plant chemical composition. Several plant responses to UV-B are mediated by a protein called UVR8 and the defence response to herbivory involves the regulatory molecule jasmonic acid. In this project, we will examine the potential of UVR8 and a protein called MYC2 that mediates the response to jasmonic acid to increase resistance to insect herbivory in oilseed rape. We will test whether transgenic over-expression of specific genes increases resistance to insect herbivory as 'proof of concept' that manipulation of the UV-B response could be used to develop new varieties.

Attack by various pests and pathogens causes significant losses to the oilseed rape crop and considerable expense is incurred in trying to counter this problem by using pesticides. The aim of this project is to develop a novel approach to increase resistance to pest attack in oilseed rape by hyper-activation of UV-B and/or jasmonic acid (JA) signalling pathways. Exposure of plants to UV-B wavelengths has been shown to reduce the attractiveness of plants to insect herbivores. Plant responses to UV-B are mediated through several signalling pathways and hyper-activation of particular pathways may therefore increase resistance to herbivory. Jasmonic acid, which is involved in some responses to UV-B stimulates defence against attack by herbivores. In this project, we will produce transgenic lines of B. napus over-expressing the UV-B-specific regulator UVR8 and a key effector of JA signalling, the transcription factor MYC2. We will test whether these lines have increased resistance to several pests as 'proof of concept' that manipulation of the UV-B response could be used to develop new varieties. We will dentify key changes in gene expression profiles using transcriptomics and levels of secondary metabolites involved in resistance to herbivory in the over-expression lines.

The project has the potential to generate knowledge that will lead to the development of oilseed rape varieties with increased pest resistance and therefore may provide both economic benefit to the UK and societal impact through a reduction in the need to use pesticides. The recent European review of pesticide legislation within directive 91/414 EEC has identified many active ingredients that are to be withdrawn from use as commercial insecticides. This has impelled an urgent need to identify new and effective alternatives and replacements for crop protection. The target species selected for this project cover three of the most important groups of pests for oilseed rape crops. They are also representative of many invertebrate pest species that affect not only Brassica species in general, but a diverse range of other important crop species. This project aims to develop an innovative approach to crop protection that could be extended to non-Brassica species and provide significant benefits in the future. If the project leads to the development of new oilseed rape varieties that require reduced pesticide inputs it will provide significant economic benefit to companies involved in developing and selling new varieties, growers, and companies involved in processing the crop. It may therefore benefit the UK economy. The potential reduction in pesticide use will have a positive impact on society in general through benefits for health and the quality of life. Reducing pesticide use will be beneficial for growers, decrease the levels of toxins that harm ecosystems and wildlife, improve water quality and reduce pesticide residues in foods. The project will potentially benefit government agencies involved in policy making as it will hopefully demonstrate how supporting innovative science underpinning the development of new crop varieties can be successful in providing economic benefit and improving the quality of life.