Head-Space Volatile Milieu from Leaves: A Case Study of Eggplant Infestation by Mealybug

The phloem-feeder mealybug, Coccidohystrix insolita (Green, 1908) is a common herbivore which causes economic loss in crop yield every year in India. The present article is aimed at understanding the impact of mealybug infestation on metabolic system of eggplant (Solanum melongena L.). The alterations in the volatile profile have been investigated with the help of head-space-solid-phase-microextraction guided Gas Chromatography Mass spectrometry. Results showed occurrence of a reciprocal balance in  total monoterpene, sesquiterpene and oxygenated monoterpene content for protection against the mealybug attack. A significant change in volatile scenario such as 4,8-dimethylnona-1,3,7-triene (4,8-DMNT), ß-ocimene, α-bergamotene and other compounds was observed. Some of these compounds belong to Green Leaf Volatile class to respond against biological stress. Quantities of secondary metabolites, like phenolic compounds was increased in damaged leaves. This preliminary finding highlighted the role of phytochemicals (both volatile and non-volatile) in defence mechanism of eggplant during herbivore attack in the tropical and subtropical climate of India.