Phenolics in defence response of species of genus Nicotiana infected with Cucumber mosaic virus containing satellite RNA

Nicotiana megalosiphon, N. glutinosa and N. tabacum var. Samsun are used as diagnostic and propagation species in Cucumber mosaic virus (CMV) research. CMV has the widest host range for any plant virus. Some strains of CMV encapsidate evolutionary unrelated satellite RNA (CMVsat). Phenolics are widely distributed among plants and many different physiological roles, including protection of plants against biotic and abiotic stress, have been attributed to them. In order to investigate the differences in response to abiotic and biotic stress within the same species as well as between species of the same genus, changes of phenolics content in species of genus Nicotiana induced by wounding or CMVsat infection were investigated. Analysis of phenolics was performed by high performance liquid chromatography method. Samples were separated on Zorbax Rx-C18 column (75x4, 6 mm, 5 μm, Agilent Technologies) using segmented gradient at 35°C and 1 ml/min flow. Concentration of phenolics in upper untreated leaves was significantly higher compared to lower wounded or virus inoculated leaves. Most of wounded and virus inoculated plants had lower amount of phenolics in all leaves compared to untreated plants. Significant differences of phenolics content in lower or upper leaves established between untreated and wounded as well as between wounded and virus treated plants depended on the time elapsed after the treatment.