Freezing out the snow mould fungus Snow mould fungus causes devastating losses in autumn-sown cereals and grasses. A European project made significant progress in identifying mechanisms of resistance to this pathogen. Health © Shutterstock Microdochium nivale (M. nivale) can cause 50–90% losses in winter cereal crops in areas that experience bouts of cold weather. As its name suggests, the fungus can develop under snow cover. However, climate changes have exacerbated potential losses. Moreover, the pathogen can develop under humid yet chilling conditions with no snow cover. Damage of crops may be so severe that resowing of a spring variety may be necessary. The EU-funded project 'Cell wall-plasmalemma-cytoskeleton as a sensor in cold-induced plant resistance to fungal infection' (Protect CROP) investigated the natural resistance mechanism present in triticale, a hybrid of wheat and rye. Exposure of plants at the seedling stage to cold temperatures induces resistance of the plants to the fungus. This process, known as cold hardening, works by inducing interactions between the cell wall, its membrane and the cytoskeleton of the cell. Objectives of the project were to determine the type, extent and duration of the resistance response to pathogens induced in plants by cold treatment. Analysis of the role of the cell wall-plasmalemma-cytoskeleton in promoting resistance would reveal early signalling events in resistant and non-resistant plants. Finally, resistance mechanisms and pathogen-host interactions were investigated. Project results proved very encouraging to be used as a basis for inducing resistance in winter cereal crops. Prolonging cold hardening up to 90 days linearly increased resistance to pathogen attack (up to a threshold level) but extent of resistance is strongly dependent on the genetic makeup of the plant. Interestingly, the cold episode is 'memorised' and plants retain resistance during dehardening conditions for up to four weeks while a more compact cell wall is built up for passive resistance. The mechanisms of cold resistance to M. nivale are relevant to plant breeders able to incorporate resistance genes in new lines of winter cereal crops. As such, project efforts are promising for all parties with a stake in food production. These include geneticists, plant physiologists and the farming community whose livelihood depends on disease-free crop production.
