Role of Flavanolic Wall Infusions in the Resistance Induced by<i>Laccaria bicolor</i>to<i>Fusarium oxysporum</i>in Primary Roots of Douglas-fir

Abstract

When primary roots of newly germinated seedlings of Douglas-fir (Pseudotsuga menziesii) were inoculated with Laccaria bicolor, yellow-to-brown infusions were detected in many cortical cell walls beginning 13 days after initial contact with the fungus. Control roots developed only faint pigmentation in a few cortical walls. When control roots were challenged with a nonaggressive isolate of Fusarium oxysporum, the pathogen colonized intercellular spaces of the cortex and then usually penetrated cell walls to initiate intracellular colonization and lesion formation (...)