Transcriptomic and physiological response of durum wheat grain to short period of heat stress at the early grain-filling stage

Wheat is one of the most significant crops in terms of human consumption in the world. In a climate change scenario, extreme weather event such as heatwaves will be more frequent especially during the grain-filling (GF) stage and could affect grain weight and quality of crops. Molecular mechanisms underlying the response to short heat stress (HS) have been widely reported for the hexaploid wheat (Triticum aestivum) but the regulatory heat stress mechanisms in tetraploid durum wheat (Triticum turgidum ssp. durum) remain partially understood. In this work, we performed a transcriptomic analysis of durum wheat grains to HS during early GF to identify key HS response genes and their predicted regulatory networks under glasshouse conditions. Overall design: Tetraploid wheat (Triticum turgidum spp. durum) genotype Queule-INIA was grown under standard glasshouse conditions. Three seeds per pots were sowing. At flowering (Zadok 65), three principal spikes/pot with similar development and size were tagged. Two thermal treatments were performed: control treatment (ambient air temperature on glasshouse) and short HS treatment, which consisted of increasing the air temperature in a range of moderately high temperatures (20 to 32 ºC). The grain samples (complete caryopsis) at 10 days after flowering were collected after three hours of HS from four pot per replicate (two basal grains of four central spikelest from 12 spikes were polled for each replicate). Three replicates for each thermal treatments were done.