Control of Ramularia Leaf Spot in a Changing Climate

Lead Research Organisation: John Innes Centre
Department Name: Contracts Office


In research on pathology of Ramularia leaf spot (RLS), for which BBSRC funding is requested, the role of abiotic stress in inducting RLS symptoms in infected plants by abiotic stresses will be analysed. Simplified protocols of applying stress factors in high-throughput screens for Ramularia resistance in breeding nurseries will then be developed. The effects of abiotic stress on host defences and fungal development will be investigated. The effects of mlo mildew resistance on RLS in the field and lab will be studied to test the hypothesis that mlo suppresses RLS when the plant is not stressed but
aggravates symptoms in stressed plants. Variation in varieties' susceptibility to toxins produced by Rcc will be investigated and its relationship to field resistance examined. BBSRC funding is sought for part of the research on resistance genes in barley varieties. Ramularia-free seed stocks of
barley varieties will be produced as a basis for rigorous analysis of varieties' resistance. Association genetics will be used to postulate genes for RLS resistance by combining data on field and high-throughput trials of disease with data on the distribution of DNA marker alleles and the kinship of varieties. QTL analysis of RLS resistance will be done in two crosses of spring barley varieties and one of winter barley. Markers linked to significant genes for resistance, suitable for use in marker-assisted selection for RLS-resistance, will be developed. Variety-by-isolate specificity in resistance to RLS will be
studied, to evaluate the risk of varieties' resistance diminishing through the emergence of virulent Rcc isolates. Parts of the project for which BBSRC funding is not requested concern research on the epidemiology of RLS to improve disease forecasting, analysis of fungicide resistance, investigation of the contamination of barley seed by Rcc and its significance for spread of RLS, and seed treatments to control RLS in grain.


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