Multi-omics insights into salinity tolerance in African bermudagrass.

Abstract

African bermudagrass (Cynodon transvaalensis Burtt-Davy) is a key parent species used to produce interspecific hybrid bermudagrass (Cynodon dactylon × C. transvaalensis). Due to the increasing use of non-potable water for landscape irrigation, salt stress has become a major concern in the turfgrass industry. While variation in salt tolerance is known within bermudagrass, the molecular basis of this trait is not well understood, particularly in African bermudagrass. In this study, we aimed to identify the molecular mechanisms associated with salt tolerance in African bermudagrass. The first-generation selfed (S₁) population derived from African bermudagrass genotype OKC1163 was evaluated for salt stress response in controlled-environment conditions in 2024 and 2025. Phenotypic data for visual leaf firing and percent green cover were collected weekly. Using a preexisting high-density linkage map, 15 quantitative trait loci (QTLs) associated with salt response were identified on seven linkage groups. Four QTLs were consistently identified as associated with salt response across years. A total of 1261 upregulated genes, 150 upregulated metabolites, and 60 upregulated lipids were identified under salt stress using the genotype OKC1163. Combining genomic and omics analyses, several candidate genes were identified to be involved in the synthesis of abscisic acid and maltose, alteration of the salicylic acid signaling pathway, and the ABC (ATP-binding cassette) transporter pathway. The results of this study elucidated the molecular mechanisms of African bermudagrass response to salt stress and provide a foundation for future marker-assisted selection and gene function validation.