Developing an experimental protocol to test Armillaria-specific genes for their potential role in pathogenicity and virulence

Abstract

Most Armillaria species are notorious fungal pathogens that cause substantial damage to woody plants in forestry and agriculture. Their pathogenic success is attributed to specialized gene families involved in host invasion and virulent activities in the plant tissues. This study aims to investigate the expression patterns of expanded genetically diversified gene families in two Armillaria species (A. borealis and A. ostoyae) using unique Armillaria-specific gene sets, involved in degrading monocyclic aromatics, previously identified through comparative genomics analysis of gene pools related to fungal bioremediation. By analyzing differential gene expression data from high- and low-virulent isolates grown under stem invasion conditions, comparing fresh, slowly decaying stems with autoclaved dead stems, several Armillaria genes were implicated as potential plant pathogenicity or virulence factors. In conclusion, systematic plant invasion experiments combined with differential gene expression profiling focusing on new gene variants specific to Armillaria species offer a reliable and feasible framework for predicting genes related to pathogenicity and distinguishing between pathogenicity genes and potential virulence effectors.