Jasmonate

A laboratory colony of H. zea, generously provided by Dr. May R. Berenbaum (Department of Entomology, University of Illinois at Urbana-Champaign), was maintained in an insectary kept at 28 °C with a photoperiod of 16 h light: 8 h dark on a semi-synthetic control diet containing wheat germ [25 ]. Induction treatments were performed as described by Li et al. [9 (link)]. The analytical grade plant allelochemicals, xanthotoxin, chlorogenic acid, indole-3-carbinol, flavone, rutin, gossypol, 2-tridecanone, quercetin, coumarin and plant signal molecules jasmonate and salicylate, used in this study, were obtained from Sigma (Sigma-Aldrich, St. Louis, MO, USA) (Figure 1). In brief, 30 newly molted 5th instar larvae were allowed to feed on control diets or control diets containing 0.1% plant xenobiotics for 48 h. Three independent biological replicates of the control diet or each plant xenobiotic treated diet were prepared for subsequent RNA extraction. Midguts and fat bodies were then dissected out, flash-frozen in liquid nitrogen, and stored at −80 °C for subsequent RNA extraction.

All opened flowers (after stage 14) were removed from the inflorescence, and the remaining flower bud clusters were dipped into 50 µM (±) Jasmonate (Sigma) dissolved in 0.05% aqueous Tween 20.