Regulation of photosynthesis by exogenous MeJA under phosphorus deficiency: a review

Phosphorus deficiency is a critical abiotic stress that limits crop productivity, severely constraining plant photosynthesis by inhibiting light reactions and carbon assimilation. Methyl jasmonate (MeJA), as a key stress signaling molecule, plays a central regulatory role in plant adaptation to low-phosphorus environments. This article systematically reviews the physiological and molecular mechanisms by which exogenous MeJA alleviates photosynthetic inhibition under low-phosphorus stress, with a focus on its integration of phosphorus starvation and jasmonate signaling pathways through the PHR1 (PHOSPHATE STARVATION RESPONSE 1)-JAZ-MYC2 signaling module. This, in turn, coordinates a multi-layered network involving the regulation of photosynthetic enzyme activity, antioxidant defense, and phosphorus uptake and recycling. The article also explores potential approaches for improving crop phosphorus efficiency through the jasmonate signaling pathway. This review aims to provide a theoretical foundation for understanding plant phosphorus-hormone interaction mechanisms and offer new insights for stress resistance regulation and genetic improvement in crops.