Microscopic detection of HR accumulation at interaction sites of O. neolycopersici. Trypan blue staining of silenced ShNPSN11 (A,C, and E) and control (B, D, and F) plants following infection with On-lz. Co, conidium; App, appressorium; Ha, haustorium; Sh, secondary hyphae; Sa, secondary appressorium; HR, hypersensitive response. Bar, 50 μm.