As the above ground phenotype of AG8 infected Arabidopsis resembles a non-host infection without evidence of cell death or necrosis, we aimed to dissect the signalling pathways required for foliar resistance to AG8 through infecting mutants of the PEN1, PEN2 and PEN3 genes, which play roles in penetration resistance to several non-adapted pathogens and race specific resistance28,37. The gene discussed is PSENEN; the disease is infection.