Necrosis induction and H2O2 generation by Y1H2Y3, a pseudorecombinant between CMV-Y and CMV-HL, in plants of Arabidopsis Col-0. A, Necrotic symptoms on the plants infected with CMV-HL and Y1H2Y3 at 18 dpi. B, Symptoms on CMV-infected plants at 10 dpi. C, Detection of H2O2 in the Col-0 plants infected with Y1H2Y3 using the H2O2-sensitive fluorescent probe H2DCFDA. Leaves were harvested at 10 dpi and photographed using either bright-field light microscopy (BF) or fluorescence microscopy (H2O2). Note that necrosis was associated with the sites that fluoresced. D, Symptomatic Col-0 leaves (top panels) were subjected to tissue printing (bottom panels) to localize CMV.