RNA-seq of five Populus x canescens (Grey poplar) organs/tissues during periodic or chronic drought-heat stress treatment and after recovery in comparison to untreated controls

Simulating predicted future climate conditions, stress response and stress-related memory after one week of recovery were transcriptionally characterised in young and old leaves, phloem-bark, developing xylem and roots of 3-month-old Grey poplar plants that had undergone three weeks of stress or were kept under control conditions. The control conditions include ambient or elevated CO2 levels (380 µL L-1 and 500 µL L-1, respectively) with a daily maximum temperature of 27 °C. The stress conditions include a periodic and a chronic drought-heat scenario at elevated CO2 levels (500 µL L-1) with a daily maximum temperature of 33 °C. The periodic stress treatment included three cycles of reduced irrigation (50%, 60% and 70% reduction compared with the controls), each one lasting for six days; between the cycles, there were recovery periods with a duration of two days and a daily maximum temperature of 27 °C. In the chronic stress treatment, irrigation was gradually reduced for 22 days, down to 70% reduction compared with the controls. Three biological replicates were examined per group defined by a specific environmental condition (droughtPER: periodic stress, droughtCHR: chronic stress, control500: elevated CO2 control, control380: ambient CO2 control), a specific harvesting time (S: stress phase, R: recovery phase) and a specific tissue (LE1: young leaves, LE2: old leaves, PHL: phloem-bark, XYL: developing xylem, ROO: roots). For stress phase ambient CO2 control in old leaves, one replicate failed quality control.