Volatile signatures of phytoplasma presence from marigold plants showing witches’ broom and their potential as biomarkers for diagnostics

Phytoplasmas often induce phyllody symptoms at late stage of flowering. Other symptoms of infections like little leaf, stunting and witches’ broom are often confused with virus infection or nutrient deficiency. In order to search for some early signals of infections in vegetatively propagated marigold plants, volatilome profiling of infected and healthy marigold plants were undertaken through GC*GC-ToF/MS analysis. Differential emission of volatilome compounds have been observed in infected plants compared to healthy plants. Compounds like linalool, isobemeol, β-bisabolene and methyl salicylate were emitted in high amounts in infected samples. Biogenic volatile based detection of plant diseases is emerging as a promising field noninvasive technology. The volatile organic compounds can be potentially exploited as biomarkers for phytoplasma diagnostics in the early stages of the crop production.