Transcriptomic and metabolomic analysis reveal differentially expressed genes and metabolic pathways in bermudagrass under drought stress

Drought stress poses a significant challenge to turfgrass growth, particularly in the regions like southern United States, where bermudagrass (Cynodon sp.) is widely used for lawns and sports fields. Drought stress disrupts physiological processes, leading to reduced water availability, impaired photosynthesis, and oxidative stress. To understand the bermudagrass response to drought, we investigated the physiological differences and characterized the gene expression and metabolite profiles in two bermudagrass genotypes, TifTuf and Premier. Physiological measurements showed significant variations in green cover percentage, visual quality, and relative water content between the two genotypes. RNA sequencing revealed extensive gene expression changes, with differentially expressed genes that were upregulated in both genotypes. Gene ontology (GO) analysis highlighted biological processes such as transcription regulation, lipid metabolism, and cellular structure development pathways. KEGG pathway analysis indicated that TifTuf had significant changes in galactose metabolism, carotenoid biosynthesis, and plant hormone signal transduction pathways, while Premier showed enrichment in plant hormone signaling, lipid metabolism, and secondary metabolite biosynthesis pathways. Metabolomic analysis provided insights into metabolic reprogramming due to drought stress. Principal component analysis revealed distinct metabolic patterns between control and drought-stressed samples, with both genotypes showing substantial alterations. Differential metabolite analysis identified key metabolites associated with stress adaptation, including the phytohormone ABA and various amino acids. This analysis elucidates the intricate physiological and molecular mechanisms underlying drought tolerance in bermudagrass genotypes. These findings enhance the understanding of drought stress adaptation strategies in bermudagrass and offer valuable insights for the development of drought-tolerant genotypes.