Identification of Candidate Master Regulators of the Response to Early Heat Stress in Climate-adapted Wheat Landraces via Transcriptomic and Co-expression Network Analyses

Climate change is not only causing a rise of global temperature but also more variable climates. In major wheat-producing countries, spring temperatures have increased up to 40°C in recent years. Considering the wheat optimal growth temperature of around 20°C, wheat is particularly prone to damage by heat stress. To combat this threat, it is imperative to understand the response of wheat to early heat stress. This research is focus on understanging the transcriptional reprogramming of wheat when exposed to heat stress during the three-leaf stage. Differential expression and weighted gene co-expression network analysis have been used here before and after the stress to to identify candidate master-regulators of this transcriptional response. Thirteen wheat landraces where used to asses the wheat transcriptomic response to 14-days heat stress during the early stages of development (3-leaf stage). The experiment was performed by growing the plant until 3 leaf-stage (22°C/16°C (day/night) on an 18 hour day/night cycle) and then submitting the plants to 14 days of 35°C/30°C (day/night) and three days of recovery (22°C/16°C (day/night) on an 18 hour day/night cycle) after that. Four replicates, per treatment, per landrace accession were used in this experiment. mRNA-Seq analysis was performed on RNA material collected at the 3-leaf stage and after the heat stress.