Vol. 5, Issue 1 (2020)
Nutritional sink formation in galls of Millettia Pinnata synergistically infected by Myricomyia Pongamiae and Eriophyes Cheriani
Author(s): Myrene RD, Reshma S, Renuka R
Abstract: Investigation of source and sink relationships between galls and their host plants often invoke exploration of nutrition, environment and enemy hypotheses. According to the nutrition hypothesis, resource manipulation and endophagy are typical of insect-plant gall interaction, in which galls act as nutritional sinks providing insects with essential nutrients needed for their growth and development. The galling insect controls the nutrient levels in the gall for their own benefit. Insect galls (G), galled leaves (GL) and healthy leaves (HL) of Millettia pinnata infested synergistically by the galling insects Myricomyia pongamiae and Eriophyes cheriani were collected to study the various changes resulting from biotic stress challenged with insect feeding. There is mobilization of nutrients like reducing sugar, total soluble sugars (TSS), starch, and proteins into gall tissues from the ungalled region of the leaves. Higher concentrations of total phenols (TP) and ortho-dihydric phenols (OP) were reported in galled leaves. Biomarkers of stress such as H2O2, malondialdehyde, proline and ascorbic acid were reported to be in higher levels in galled leaf tissues. In addition, levels of reduced glutathione, a non-enzymatic antioxidant responsible for scavenging free radicals declined in infected leaves. Antioxidant enzymes like glutathione reductase, peroxidases and phenol oxidase were found to possess higher activities in galls and galled leaf when compared to healthy leaf tissue.