Enhancing Plant Resistance at the Seed Stage: Low Concentrations of Methyl Jasmonate Reduce the Performance of the Leaf Miner Tuta absoluta but do not Alter the Behavior of its Predator Chrysoperla externa

Abstract

Plants express inducible direct and indirect defenses in response to herbivory. The plant hormone jasmonic acid (JA) and related signaling compounds referred to as jasmonates play a central role in regulating defense responses to a wide range of herbivores.We assessed whether treating tomato seeds with 0.8 mM of methyl jasmonate (MeJA) affected the performance of the leaf miner Tuta absoluta, and whether possible changes in volatile profiles altered the behavior of its predator Chrysoperla externa. MeJA-treatment significantly lengthened larval development and decreased the pupal weight of T. absoluta. Herbivory alone increased the emissions of α-pinene, 6-methyl 5-hepten-2-one, β-myrcene, (E)-β-ocimene, isoterpinolene, TMTT, (Z)-3-hexenyl butyrate, and hexyl salicylate. MeJA seed treatment significantly decreased the emissions of α-cubebene from undamaged and herbivore-infested plants. In addition, the emissions of several compounds were lower in the absence of herbivory. Chrysoperla. externa preferred odors from herbivore-infested plants over those from control plants, regardless of the MeJA-treatment, and they did not show any preference for herbivore-infested plants for any of the MeJA-treatments. Our results show preliminary evidence that the treatment of tomato seeds with MeJA can reduce the performance of Tuta absoluta, and that the chemical differences observed in plant VOC profiles do not alter the behavior of the model predator.

Interrelated responses of tomato plants and the leaf minerTuta absolutato nitrogen supply

“…These include the induction of the JA signalling pathway but also activity of other defence enzymes and the emission of volatile organic compounds, which have recently been shown to increase in T. absoluta ‐infested tomato plants (Strapasson et al . ).…”

“…The defence responses of tomato or other solanaceous plants to T. absoluta are few in the literature and restricted to the induction of volatile organic compounds (Strapasson et al . ; De Backer et al . ).…”

“…Further study restricting analyses to the attacked tissues would be necessary to clarify this point. The defence responses of tomato or other solanaceous plants to T. absoluta are few in the literature and restricted to the induction of volatile organic compounds (Strapasson et al 2014;De Backer et al 2015). However, studies involving insects from the same feeding guild may explain the seemingly low defence response of tomato to T. absoluta.…”

“…In order to confirm these assumptions, however, it will be necessary to determine the impact of LN on other tomato inducible responses. These include the induction of the JA signalling pathway but also activity of other defence enzymes and the emission of volatile organic compounds, which have recently been shown to increase in T. absoluta-infested tomato plants (Strapasson et al 2014).…”

Analysis of key genes of jasmonic acid mediated signal pathway for defense against insect damages by comparative transcriptome sequencing

“…These similarities to defense responses against insect herbivory make it possible to stimulate plant resistance before insect attack. Such a strategy may become useful in future pest management strategies 14 , employing MeJA or other stimuli of JA pathways such as hexanoic acid 15 .…”