WPGP/WHISP HR

Hypersensitive Response to Cronartium ribicola in sugar pine needles

When challenged with C. ribicola spores, sugar pine needles with major gene resistance (Rr) exhibit the classical hypersensitivity response. Plant cells immediately adjacent to the area of fungal infection become disorganized and die, producing necrotic flecks surrounded by healthy tissue (bottom). Sensitive (rr) needles have large yellow patches of infected tissue (top)