Abbas, A.He, J.Wang, Y.Jiang, W.Naznin, A.Budhathoki, R.Bose, J.Donovan-Mak, M.Zhou, M.Li, C.Varshney, R.K.Chen, Z.-H.2025-09-252025-09-252025BMC Plant Biology, 2025; 25(1):864-1-864-161471-22291471-2229https://hdl.handle.net/2440/147543Climate-induced heat and drought stress significantly reduce wheat productivity, posing a major challenge, identifying and developing tolerant wheat varieties is a key priority of modern breeding programs. The stay-green phenotype is characterized by sustained photosynthesis and extended grain-filling period under stress conditions, plays a pivotal role in enhancing tolerance. Here, we evaluated 4 commercial Australian wheat cultivars (Coota, Catapult, Beckom, and Sunmaster) in a greenhouse conditions, assessing their physiological, and agronomic traits under heat and combined heat-drought stress. Beckom demonstrated superior heat and combined heat-drought stress tolerance and recovery, maintaining 50% higher photosynthetic and 45% higher transpiration rates in comparison to the sensitive variety, as well as the highest stay-green trait, proline content, and yield. In contrast, Coota exhibited the most severe declines in physiological traits reflecting sensitivity. Expression levels of key genes involved in stomatal regulation, chlorophyll degradation, and heat shock responses in flag leaf tissue showed, significantly higher expression (1.9 and 1.7 folds) of TaGORK (Outward-Rectifying K+channel) gene critical for stomatal regulation is found in Beckom. In contrast, stress-sensitive Coota showed significantly higher expression of (4.5 and 0.68 folds) TaHPX (Haem Peroxidase) and (3.3 and 1.7 folds) TaLOX (Lipoxidase), indicating increased reactive oxygen species (ROS) production and chlorophyll degradation. This study underscores the complexity of physiology processes underlying the stay-green trait and suggests the involvement of multiple pathways including stomatal regulation and chlorophyll degradation. Also, we have identified physiological, biochemical, and genetic traits that may serve as potential phenotypic markers for marker-assisted selection (MAS) aimed at developing tolerant wheat varieties. While these traits show promise, further validation is necessary in future studies, to support sustainable food production in future.en© The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.Biochemical traits; Stay green trait; Gene expression; Heat stress; Combined heat and drought stress; Physiological traits; Triticum aestivum LJournal article10.1186/s12870-025-06831-0744102Chen, Z.-H. [0000-0002-7531-320X]