Abstract:
Intersterility (IS) is thought to prevent mating compatibility between homokaryons that belong to different
species. Although IS in Heterobasidion is regulated by the genes located at the IS loci, it is not yet
known how the IS genes influence sexual compatibility and heterokaryon formation. To increase our
understanding of the molecular events underlying IS, we studied mRNA abundance changes during IS
compatible and incompatible interactions over time. The clustering of the transcripts into expression profiles,
followed by the application of Gene Ontology (GO) enrichment pathway analysis of each of the clusters,
allowed inference of biological processes participating in IS. These analyses identified events
involved in mating and sexual development (i.e., linked with IS compatibility), which included processes
associated with cell–cell adhesion and recognition, cell cycle control and signal transduction. We also
identified events potentially involved in overriding mating between individuals belonging to different
species (i.e., linked with IS incompatibility), which included reactive oxygen species (ROS) production,
responses to stress (especially to oxidative stress), signal transduction and metabolic biosynthesis. Our
findings thus enabled detection and characterization of gene expression changes associated with IS in
Heterobasidion, as well as identification of important processes and pathways associated with this phenomenon.
Overall, the results of this study increase current knowledge regarding the molecular mechanisms
underpinning IS in Heterobasidion and allowed for the establishment of a vital baseline for further
studies.
