Relative expression of selected genes measured by qPCR. Different patterns of gene expression were observed for S. lycopersicoides and S. lycopersicum inoculated with B. cinerea. Induction of (A) a PR1 protein-encoding gene was delayed in S. lycopersicum compared to S. lycopersicoides, but expression at 48 hours after inoculation (hai) was comparable in both Solanum species. Induction of (B) a beta-1,3-glucanase-encoding gene and (C) a subtilisin-like protease-encoding gene was also delayed in S. lycopersicum; however, expression at 48 hai was reduced compared to S. lycopersicoides. Induction and expression of (D) a glutathione S-transferase-encoding gene were comparable between S. lycopersicum and S. lycopersicoides. Expression of (E) a ribulose-1,5-bisphosphate carboxylase-encoding gene and (F) a glycolate oxidase-encoding gene decreased over time in both S. lycopersicum and S. lycopersicoides, but the rate and overall reduction of expression was greater in S. lycopersicoides. Genes were selected for qPCR analysis based on expression and predicted role in pathogen defense. Blue bars represent expression of genes in S. lycopersicoides relative to timepoint 0. Red bars represent expression of genes in S. lycopersicum relative to timepoint 0.