The Role of Photorespiration in Enhancing Plant Resilience to Heat Stress

Abstract

Photorespiration, initiated by RuBisCO's oxygenation activity, results in the production of 2-phosphoglycolate, which must be recycled through energy-intensive reactions. These processes consume ATP and NADPH, release CO2, and generate ammonia, traditionally framing photorespiration as inefficient due to the associated carbon and energy loss. Elevated temperatures exacerbate photorespiration by increasing RuBisCO’s affinity for oxygen. However, under heat stress, photorespiration plays a protective role by dissipating excess energy, detoxifying harmful byproducts, and mitigating reactive oxygen species. This review highlights the adaptive functions of photorespiration during heat stress, emphasizing the natural upregulation of numerous photorespiratory genes in response to elevated temperatures. A potential strategy to enhance heat tolerance through co-overexpression of the photorespiratory genes PGLP1 and GOX1 in Arabidopsis thaliana is proposed, although this concept remains theoretical and requires experimental validation. Significant knowledge gaps persist regarding the roles of many photorespiratory genes during heat stress and the integration of the photorespiratory pathway with primary metabolism under elevated temperatures. Advancing our understanding of photorespiration through refined models and improved metabolic flux analysis holds promise for harnessing its protective potential to enhance plant resilience, reduce heat stress impacts, and safeguard crop productivity in a warming climate.