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Durable cereal disease resistance: the physiological, biochemical and genetic basis. - CE0154

Description
Genetic host plant resistance offers disease control that is potentially far more desirable than the application of fungicides. MAFF recognises the potential contribution more durable forms of resistance may make to sustainable systems for crop production and management. However, the rapid evolution of pathogen virulence has nullified many single genes for resistance to fungal leaf diseases that have been used by plant breeders and deployed in UK cereal cultivars. Durable resistance is available, but it is generally under complex genetic control, and therefore difficult to exploit. Powdery mildew is a consistent constraint on the efficient production of wholesome cereals. The current project is aimed at understanding the basis of durable resistance to powdery mildew in cereals in order to facilitate its exploitation through plant breeding.

The proposed studies will have two principal foci. The first will explore resistance mechanisms that interfere with early processes of fungal growth and development that are essential for the formation of infection structures used to attack the plant: features of leaf epicuticular waxes will receive particular attention. The second will concentrate on mechanisms by which plant cells recognise and respond to attack by erecting barriers that prevent or impede infection, and thus convey resistance: understanding the important role of plant phenolic compounds will provide a central theme. Understanding the physiological, biochemical and genetic basis of different resistance mechanisms, and combining them to provide complex barriers, will facilitate plant breeding for durable resistance.
Objective
The central objective is to increase understanding of resistance to biotrophic fungal pathogens of cereals with the immediate target of facilitating breeding for durable resistance to powdery mildew (Erysiphe graminis ) by :

01. Assessment of a range of oat and barley genotypes for new sources of resistance, with emphasis on identifying genotypes with high penetration resistance associated with accumulation of autofluorescent phenolic compounds in attacked leaf epidermal cells. Informing plant breeders with a view to incorporating potentially valuable germplasm into breeding programs [ongoing throughout project]. This objective to be pursued in conjunction (consultation, and exchange of material and information) with CEO155 (JKM Brown, JIC).

02. Investigation of factors that promote and impede infection structure (appressorium) formation: to identify novel resistance factors for exploitation (ongoing with appropriate updates of milestones by agreement with MAFF).

03. Investigation of the significance and mechanistic basis of induced cellular inaccessibility on the expression of resistance: Assessing the consequences of polycyclic attack on the expression and evaluation of durable resistance (by end year 4). This objective to be partially assisted through results of modelling studies in CE0155 (JKM Brown, JIC).

04. Evaluation of the suppressive effects of fungal colony establishment on cellular accessibility induced in the vicinity of developing fungal colonies: to develop methods of assessing post-infection resistance (by end year 4).
Project Documents
• Final Report : Durable cereal disease resistance: the physiological, biochemical and genetic basis   (95k)
Time-Scale and Cost
From: 1998

To: 2003

Cost: £699,523
Contractor / Funded Organisations
Institute of Grassland and Environment Research (IGER)
Keywords
Arable Farming              
Biotechnology              
Crop Diseases              
Crop Improvement              
Farming              
Sustainable Production              
Wheat Production              
Fields of Study
Arable Crops