Screening for costs of disease resistance caused by stomatal dysfunction

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

Abstract

The role of abiotic stress in inducting Ramularia leaf spot (RLS) symptoms in infected barley 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 Ramularia collo-cygni (Rcc) will be investigated and its relationship to field resistance examined.

Resistance genes in barley varieties will be investigated. 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 LINK project which are not funded by BBSRC funding 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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