Tomato leaflet colonized by the fungal pathogen Sclerotinia sclerotiorum (red, expressing the GFP) viewed under fluorescent illumination. The agar plug used as inoculum is visible in cyan at the center of the picture. The fungus S. sclerotiorum is notorious for infecting hundreds of plant species. Sucher et al. (pp. 1820-1844) analyzed the transcriptome of plants from six botanical families to document the diversity of molecular responses to this pathogen. About one third of plant transcriptomes responded locally to S. sclerotiorum inoculation, including a high proportion of broadly conserved genes showing frequent regulatory divergence at the interspecific level. Photo by Marielle Barascud.