Investigating a Role for BLADE-ON-PETIOLE Genes in Plant Defense

Plants have evolved multiple layers of defense to ward off pathogens. Pathogen-associated molecular pattern (PAMPs)-triggered immunity (PTI) is the most ancient and basal form of plant defense. BLADE-ON-PETIOLE1/2 (BOP1/2) are members of an evolutionarily conserved subclade of BTB-ankyrin proteins that control plant development within the NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES1 (NPR1) family of plant defense regulators that control systemic acquired resistance. I analyzed the transcriptome of BOP1 overexpressing plants to find a previously undiscovered role for BOPs in plant defense. Gene Ontology analysis revealed that 35% of upregulated genes belong to plant defense pathways with PTI forming the largest group. Among these PTI genes were clade I TGA factors, also essential for BOP-mediated developmental processes. Data validation and direct pathogen testing support the model that BOPs and clade I TGAs co-regulate a subset of genes involved in PTI. These data uncover dual role for Arabidopsis BOPs in development and defense.