Antimycin A Improves Heat Tolerance in Creeping Bentgrass by Suppressing Nighttime Respiration and Reprogramming Carbon and Nitrogen Metabolism

ABSTRACT

High temperature causes an increase in plant respiration, which may contribute to growth decline under heat stress. The objectives of this study were to investigate whether suppressing heat‐elevated dark respiration with a respiration inhibitor, antimycin A (AA), could improve heat tolerance and alter carbon and nitrogen‐containing metabolite pools in creeping bentgrass ( Agrostis stolonifera “Penncross”). Plants received water or foliar AA under 25°C/15°C or 35°C/35°C day/night conditions for 35 days. Turf quality, photosynthesis (Pn), and nighttime respiration (Rn) were measured weekly, and leaf metabolites were analyzed at Day 35. Under 35°C/35°C, AA‐treated plants maintained higher turf quality from Days 14–35, higher Pn, and lower Rn than plants not treated with AA. AA treatment increased the relative levels of glucose, cellobiose, and multiple amino acids, including proline, glutamine, asparagine, and γ‐aminobutyric acid. Pyruvate and shikimate increased, whereas α‐ketoglutarate decreased; malate and isocitrate did not differ significantly. By combining physiological measurements with metabolite profiling, this study identifies carbohydrate conservation and changes in carbon and nitrogen metabolism as potential contributors to AA‐associated heat tolerance in creeping bentgrass.