Decoding chilling temperature adaptation in bermudagrass:Temporal transcriptomic and metabolomic dynamics in tolerant and sensitive genotypes

Authors: GHIMIRE, KRISHNA - Purdue University; Serba, Desalegn; AMUNDSEN, KEENAN - University Of Nebraska; WU, YANQI - Oklahoma State University; Barnaby, Jinyoung

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2026
Publication Date: 6/19/2026
Citation: Ghimire, K., Serba, D.D., Amundsen, K., Wu, Y., Barnaby, J.Y. 2026. Decoding chilling temperature adaptation in bermudagrass: Temporal transcriptomic and metabolomic dynamics in tolerant and sensitive genotypes. Crop Science. 66(3). Article e70317. https://doi.org/10.1002/csc2.70317.
DOI: https://doi.org/10.1002/csc2.70317

Interpretive Summary: Bermudagrass is widely used in warm-season landscapes, but its limited ability to tolerate cold restricts its use in cooler regions. While earlier studies have provided important insights into how plants react immediately after cold stress begins, much less is known about how these responses develop and change over time. In this study, we used an integrated approach combining gene expression and metabolite profiling to track how bermudagrass adjusts to prolonged cold conditions. Our results reveal that plants coordinate protective genes and key compounds, such as sugars and amino acids, in a dynamic and staged manner to strengthen their defenses against cold damage. By uncovering these molecular and metabolic strategies, this research provides new insights into how bermudagrass adapts to extended periods of low temperature and identifies potential targets to support the development of cold-tolerant warm-season grasses.

Technical Abstract: Cold tolerance is a critical trait limiting the adaptation and utility of bermudagrass (Cynodon dactylon) in temperate regions, yet the temporal regulation of molecular and metabolic responses during sustained cold exposure remains poorly understood. Previous transcriptomic studies have provided valuable insight into the rapid responses within the first 12–24 hours of cold acclimation, but less is known about how these responses progress and are maintained over multiple days. Here, we integrated transcriptomic and metabolomic analyses to investigate the dynamic regulation of cold responses in two contrasting genotypes—the cold-tolerant cultivar TifTuf and the cold-sensitive genotype OSU2074—across days 1, 2, and 4 of exposure to 4°C. By analyzing transitions from day 1 to 2, day 2 to 4, and cumulatively from day 1 to 4, we distinguished transient early responses from sustained regulatory mechanisms and cumulative metabolic shifts. TifTuf exhibited extensive transcriptional reprogramming, including strong induction of transcription factors, ABA signaling components, and protective proteins, whereas OSU2074 showed a comparatively limited response. Metabolomic profiling revealed that TifTuf maintained higher levels of osmoprotective amino acids (e.g., proline, valine, lysine) and sugars (e.g., raffinose, galactinol, myo-inositol) during early stages, followed by progressive accumulation of raffinose, sucrose, and valine as cold exposure continued. In contrast, OSU2074 primarily accumulated fructose, serine, glycine, and aconitic acid, suggesting a distinct metabolic strategy. Coordinated increases in valine, sucrose, and raffinose in TifTuf were consistent with upregulation of valyl-tRNA synthetase (OsValRS1), sucrose synthase (SUS2), sucrose phosphate synthase (SPS1), and sucrose-phosphate phosphatase (SPP2). Together, these findings reveal a dynamic, stage-specific coordination between transcriptional and metabolic pathways that underlies bermudagrass cold acclimation beyond the immediate early response. By capturing the temporal evolution of regulatory networks and metabolite adjustments, this study provides new insights into mechanisms of cold tolerance and identifies candidate genes and metabolites that may inform future breeding strategies for improved winter survivability in warm-season grasses.