A cytosolic glyoxylate shunt complements the canonical photorespiratory pathway in Arabidopsis

作者：Xiaotong Jiang, Amanda M. Koenig, Berkley J. Walker, Jianping Hu · 发表于：Nature Communications · 年份：2025 · DOI：10.1038/s41467-025-59349-2 · 被引用次数：14 · 研究领域：Photosynthetic Processes and Mechanisms、Plant Stress Responses and Tolerance、Plant Gene Expression Analysis

Photorespiration functions in part to support photosynthetic performance, especially under stress such as high light, yet the underlying mechanisms are poorly understood. To identify modulators of photorespiration under high light, we have isolated genetic suppressors of the photorespiratory mutant hpr1 (hydroxypyruvate reductase 1) from Arabidopsis. A suppressor that partially rescues hpr1 is mapped to GLYR1, which encodes the cytosolic glyoxylate reductase 1 that converts glyoxylate to glycolate. Independent glyr1 mutants also partially rescue hpr1 and another photorespiratory mutant, catalase 2. Our genetic, transcriptomic and metabolic profiling analyses together reveal a connection between cytosolic glyoxylate and a non-canonical photorespiratory route mediated by HPR2, which we name the photorespiratory glyoxylate shunt. This shunt complements the canonical photorespiratory pathway and is especially critical when high photorespiratory fluxes are required and when the major photorespiratory pathway is deficient. Our findings support the metabolic flexibility of photorespiration and may help to improve crop performance under stress. Our understanding of the mechanisms underlying the role and regulation of photorespiration in plant response to high light is still limited. Here, the authors report a cytosolic glyoxylate shunt for photorespiration that can reduce carbon retention in the photorespiratory intermediates that are toxic to plants.