Drought Priming May Enhance the Tolerance of Cotton Seedlings to Subsequent Drought Stress

Enhancing water use efficiency is a key strategy to improve drought resistance in cotton. Although drought priming has been recognized for enhancing plant tolerance to drought, its impact on upland cotton remains uncertain. In a pot trial with Xinluzao19, we studied the influence of soil drought and drought priming on seedlings. Primed plants maintained similar height to non-primed ones but showed significant differences in hydrogen peroxide, malondialdehyde, and enzyme activities, indicating improved reactive oxygen species (ROS) homeostasis. Transcriptome analysis revealed 1441 upregulated genes and 12,024 downregulated genes in RD6D compared to D6D. GO enrichment and KEGG metabolic pathway analysis also revealed that numerous stress-related genes and defense pathways were significantly enriched. Some genes linked to ascorbate peroxidase and superoxide dismutase displayed similar expression profiles with enzymatic activities. These insights contribute to enhancing cotton and overall crop productivity, particularly under water-deficit conditions.