Changes in primary metabolite content may affect thrips feeding preference in soybean crops

Abstract

Past research has characterized the induction of plant defenses in response to chewing insect damage. However,little is known about plant responses to piercing-sucking insects that feed on plant cell-contents like thrips(Caliothrips phaseoli). In this study, we used NMR spectroscopy to measure metabolite changes in response to sixdays of thrips damage from two field-grown soybean cultivars (cv.), known for their different susceptibility toCaliothrips phaseoli. We observed that thrips damage reduces sucrose concentration in both cultivars, whilepinitol, the most abundant leaf soluble carbohydrate, is induced in cv. Charata but not in cv. Williams. Thrips didnot show preference for leaves where sucrose or pinitol were externally added, at tested concentration. Inaddition, we also noted that cv. Charata was less naturally colonized and contained higher levels of trigonelline,tyrosine as well as several compounds that we have not yet identified. We have established that preferencefeedingclues are not dependent on the plants major soluble carbohydrates but may depend on other types ofcompounds or leaf physical characteristics.