Metabolomic responses of Schinus terebinthifolia to oviposition and nymphal establishment of the leaf galling insect Calophya lutea

Schinus terebinthifolia (Brazilian peppertree, BP) is an aggressive, invasive weed in Florida, displacing native vegetation and forming dense monocultures that can interfere with the natural processes of invaded ecosystems. Biological control is a safe and sustainable method to control invasive species and is recommended for BP. Calophya lutea, a host specific, gall-inducing insect from Brazil is under study as potential biological control agent of BP in Florida. The nymphal stages of Calophya are sedentary and depend on the response of the plant to complete their development. The induction of secondary metabolites caused by herbivores is common and described in several plant-herbivore systems. The objective of this study was to investigate the metabolic responses of hypersensitive and susceptible BP to C. lutea oviposition and immature feeding. To measure the metabolites, half of the branches on a BP plant were protected from C. lutea. Leaf disk samples were collected before and after oviposition and after nymphal establishment and analyzed by LC-MS. Several metabolites were produced after oviposition and nymphal establishment including the amino acids glycine, proline, and serine. Alanine and arginine were higher on BP plants after C. lutea oviposition. Hypersensitive plants had higher levels of shikimic acid than susceptible plants. Alanine and glycine were significantly higher on leaves with eggs than on leaves without eggs. These metabolites are produced by plants to help cell signaling and activate defenses, they also help plants to increase growth after injury, and play roles in plant responses to biotic and abiotic stress.