Bottom-up effects of fertilization and jasmonate-induced resistance independently affect the interactions between tomato plants and an insect herbivore

Abstract

Whether nutrient availability interacts with induced resistance to alter plant chemistry and, consequently, the preference and performance of herbivores on plants remains unclear. We hypothesized that changing fertilizer inputs modulates responses induced by exogenous application of the defensive phytohormone methyl jasmonate (MeJA) against Tuta absoluta, a devastating pest of tomatoes. We found that tomato plants grown at or 2-fold above optimal fertilizer rates had higher nutrient content and were more preferred by T. absoluta females for oviposition and were better hosts for their offspring. MeJA increased phenolic content and volatile emissions in plants, which correlated with lower T. absoluta oviposition preference and offspring performance. However, we found no significant interactions when fertilizer and MeJA were applied simultaneously, such that induced responses against T. absoluta in tomatoes were similar regardless of fertilizer rate. These results provide novel insights into the bottom-up effects of fertilization and induced resistance on plant-insect herbivore interactions.