Updated project metadata. In order to study in detail short and mid term heat stress molecular response we performed a shotgun proteomics study. One-year-old P. radiata seedlings (plant size ∼33 ± 4 cm) were kept in 1 dm3 pots under a photoperiod of 16 h (400 µmol m−2 s−1) at 25 °C and 50% relative humidity (RH), and 15 °C and 60% RH during the night period. The plants were previously acclimated over a 1-month period inside the climate chamber, being watered with nutritive solution (N : P : K, 5 : 8 : 10). In order to perform a realistic experiment, and corresponding with the dawn, heat exposure treatment began with an increasing temperature gradient from 15 to 40 °C over 5 h, which was then maintained for 6 h; after that, temperature was gradually decreased from 40 to 15 °C over 5 h. This experimental procedure was repeated for 5 days and sampling was performed at: 3 h after 40 °C was reached on Day 1 (T1/2) and at the end of the 6 h heat exposure on Day 1 (T1), Day 2 (T2), Day 3 (T3) and Day 5 (T5) (Figure 1a). Plants were watered every day to 80% full capacity (FC) in order to avoid a collateral drought stress. A group of control plants was also collected on Day 1 (C) before starting the heat exposure.