Mining differentially expressed genes in Fagus crenata seedlings in response to short-term soil drought stress

We analyzed the transcriptional response of current-year Fagus crenata (beech) seedling leaves after exposure to short-term drought. Following well-watered and water-stressed treatments, we mapped the RNA-seq reads from the sampled leaves and identified 127 differentially expressed genes (DEGs), of which 89 were upregulated and 38 downregulated in water-stressed plants. Several dozen upregulated DEGs were predicted to encode proteins that facilitate mitigating processes or help avoid the adverse effects caused by drought stress, including stomatal closure, reactive oxygen species (ROS) scavenging, abscisic acid (ABA) accumulation and response, and accumulation of osmoprotectants. The functional category of sulfate assimilation was enriched in upregulated DEGs, although there was also evidence of sulfur deficiency. These results suggest the existence of molecular mechanisms in beech that are common to other plant species, representing an acclimation response to drought stress as well as sulfur metabolism under drought stress conditions.