Phosphorus-induced restructuring of the ascorbate–glutathione cycle and lignin biosynthesis alleviates manganese toxicity in peach roots.

This article focuses on the physiological and molecular mechanisms by which phosphorus (P) application alleviates manganese (Mn) toxicity in peach (Prunus persica) roots grown under acidic conditions. Excessive Mn uptake disrupts root architecture and induces oxidative stress, but P supplementation improves root growth by reducing reactive oxygen species (ROS) accumulation, enhancing antioxidant enzyme activities (including those in the ascorbate–glutathione cycle), and increasing lignin biosynthesis to strengthen cell wall integrity. Transcriptomic analyses revealed that P modulates the expression of genes involved in phenylpropanoid metabolism, antioxidant defense, and metal transporters—downregulating Mn uptake transporters (e.g., NRAMP) while upregulating vacuolar sequestration transporters (e.g., ABC, VIT, ALMT)—thereby reducing Mn accumulation in roots. These findings provide insights into P-mediated mitigation of Mn toxicity and suggest potential strategies for managing heavy metal stress in peach orchards and similar perennial crops.