The detection of hydrogen peroxide involved in plant virus infection by fluorescence spectroscopy

The production of reactive oxygen species (ROS) forms part of the defense reaction of plants against invading pathogens. ROS have multifaceted signaling functions in mediating the establishment of multiple responses. To verify whether hydrogen peroxide (H2O2) contributes to plant virus infection and the development of induced symptoms, we used fluorescence to monitor the generation of H2O2 and confocal laser scanning microscopy (CLSM) to investigate the subcellular distribution of H2O2 in leaves. In this study, the M strain of Cucumber mosaic virus (M-CMV) induced heavy chlorotic symptoms in Nicotiana tabacum cv. white burley during systemic infection. Compared with mock-inoculated leaves, H2O2 accumulation in inoculated leaves increased after inoculation, then decreased after 4days. For systemically infected leaves that showed chlorotic symptoms, H2O2 accumulation was always higher than in healthy leaves. Subcellular H2O2 localization observed using CLSM showed that H2O2 in inoculated leaves was generated mainly in the chloroplasts and cell wall, whereas in systemically infected leaves H2O2 was generated mainly in the cytosol. The levels of coat protein in inoculated and systemically infected leaves might be associated with changes in the level of H2O2 and symptom development. Further research is needed to elucidate the generation mechanism and the relationship between coat protein and oxidative stress during infection and symptom development. Copyright (c) 2016 John Wiley & Sons, Ltd.