Figure 1. Time course of Arabidopsis treatment with egg deposition, chilling and/or herbivory.

(a) Seven weeks old Arabidopsis thaliana plants were exposed to a primary stimulus (P) ‘Pieris brassicae egg deposition’ or ‘chilling at 4 °C’, respectively. After five days, the eggs were removed or plants were returned to 20 °C. After a one-day-deacclimation period a secondary stimulus ‘feeding by P. brassicae larvae’ was applied for two days, here referred to as secondary triggering stimulus (T). Leaf tissue (see panel b) was harvested at three time points: (i) after a 5-day-treatment period with the primary stimulus ‘egg-deposition’ (P₁E) or ‘chilling’ (P₁*) and from untreated control plants (C₁); (ii) one day after removal of eggs from ‘egg-deposition’-treated plants (P₂E), after one day of deacclimation of ‘chilling’-treated (P₂*), and of untreated control plants (C₂) of the same age; (iii) after two days with/without the secondary triggering stimulus ‘larval feeding’ of ‘egg-deposition’-treated (P₃E + T/P₃E), ‘chilling’-treated (P₃* + T/P₃*), and untreated control plants (T/C₃). (b) A 1 cm wide leaf strip proximal to the ‘egg deposition’ and/or ‘larval feeding’ treated area was harvested for transcriptome analysis. From ‘chilling’-treated and untreated plants, a corresponding leaf area was harvested. The circle around the larvae indicates the clip cage trapping the larvae.