Periodic Report Summary - PROTECT CROP (Cell wall-plasmalemma-cytoskeleton as a sensor in cold-induced plant resistance to fungal infection) Microdochium nivale (Fr.) Samuels and Hallett, is the most widespread snow mould fungus caused loses reaching over 50-90 % of autumn sawn cereals and grasses. The PROTECT-CROP project focused on the mechanisms of cold-induced plant resistance against M. nivale fungal pathogen followed by their practical application in healthy and environmentally friendly methods of plant protection. The mechanisms of cold induced plant resistance to M. nivale were partly dissected during our work: (1) Prolonged (0 - 98 days) cold hardening linearly triticale resistance to infection with M. nivale; however, threshold stress-levels should be accomplish to effective plant survival after infection. The level of achieved of cold-induced resistance is strongly dependent on plant genotype and virulence of M. nivale pathotypes. (2) Cold episodes are physiologically 'memorised' in plants and cold-induced resistance is kept at least during 3-4 weeks of dehardening weather. Plants during dehardening develop passive defense e.g. build more compact cell wall. (3) Two types of plant resistance are suggested: resistance to the establishment of the initial infection and resistance to hyphal invasion through the plant tissue. The cell wall physical-chemical state (structure, composition, stability) and physiological state (e.g. generation of reactive oxygen species by cell wall enzymes) brought by exposure to cold determined the resistance of both types. (4) Plasmalemma is the sensor in cold induced resistance. Its dynamic and composition changed with the cold treatment, and specific membrane proteins are important to absorption of fungal-originated substances. (5) Effective photosynthesis is the key regulator of the switch between two signalling processes: acclimation to cold and acquired resistance to pathogens. Results showed, that photosynthesis under non-optimal conditions (low temperature and suboptimal light conditions) caused excess excitation energy followed by reactive oxygen species accumulation. They restrict development of pathogens; however, simultaneously reactive species oxidize the plant membrane components and are origin of fotoinhibiton. Therefore, we confirmed, that survival of triticale resistant varieties under cold and infection results mainly from balanced photosynthesis. Our results are interesting not only for biologists, but also for industrial partners involved in plant breeding, evaluation of crop and seed quality, food quality and environment protection. Cold-induced resistance to M. nivale supported by the mechanism partly recognised during our work can be effectively transferred to new lines obtained from the crossing of the susceptible and the resistant varieties: 3,2 % of doubled haploid lines from such cross had lower survival capability to susceptible variety, 63,2 % lines did not differ from the resistant variety and 33,6 % lines out-crossed the better parent and fully regenerated after infection. Documents connexes Periodic Report - PROTECT CROP (Cell wall-plasmalemma-cytoskeleton as a sensor in cold-induced plant resistance to fungal infection)
