WHITE PINE BLISTER RUST (WPBR) CAUSED BYCRONARTIUM RIBICOLAIS A DEVASTATING FUNGAL DISEASE CAUSING GREAT ECONOMIC AND ECOLOGICAL LOSS IN LONG-GENERATION FIVE-NEEDLE PINES SUCH AS SUGAR PINE (PINUS LAMBERTIANA) IN NORTH AMERICA. THIS PROJECT WILL INVESTIGATE THE WHITE PINE BLISTER RUST (WPBR) - SUGAR PINE PATHOSYSTEM TOUNDERSTAND THE ROLE OF DNA METHYLATION IN REGULATING TRANS-GENERATIONAL IMMUNE RESPONSES.WE AIM TO I) ASSESS WHETHER THE RNA-DIRECTED DNA METHYLATION (RDDM) PATHWAY ACTIVITY IS REDUCED DURING MATURITY DUE TO A DECREASE IN THE FREQUENCY OF 24NT SMALL RNAS, RESULTING IN INCREASED TE ACTIVITY; II) IDENTIFY THE PARENTAL ENVIRONMENTAL FACTORS (BIOTIC AND ABIOTIC) THAT LEAD TO HYPOMETHYLATION AND HERITABLE INCREASED EXPRESSION OF NBS-LRR RESISTANCE GENES IN THE OFFSPRING; III) EVALUATE CHANGES IN DNA METHYLATION AND EXPRESSION OF NBS-LRR AND OTHER MAJOR GENE RESISTANCE (MGR)-RELATED GENES DURING DIFFERENT INFECTION STAGES.