A GLUTAMATE CYSTEINE LIGASE Gene StGSH1 Regulated by StERF10 Enhanced Glutathione Accumulation and Adaptation to Low Phosphorus Stress in Potato

Potato ( Solanum tuberosum L.) is a staple global food crop whose growth is constrained by soil phosphorus deficiency. While glutathione (GSH) modulates abiotic stress responses, its precise function and regulation in potato adaptation to low‐phosphorus (LP) remains undefined. This study demonstrated that LP triggers GSH accumulation by up‐regulating GLUTAMATE‐CYSTEINE LIGASE ( StGSH1 ), the rate‐limiting enzyme in GSH biosynthesis. Pharmacological inhibition using buthionine sulfoximine (BSO) and exogenous GSH supplementation confirmed the essential role of GSH in LP adaptation. Confocal microscopy showed that StGSH1‐GFP fusions localize to plastids in potato protoplasts. Overexpression and silencing of StGSH1 demonstrated that it maintained reactive oxygen species (ROS) homeostasis and attenuated LP‐induced damage. StGSH1 also coordinated membrane lipid remodeling by upregulating both phospholipid catabolic genes ( StNPC/PLD ) and sulfolipid anabolic genes ( StSQD1/2 ), shifting lipid flux from phosphatidylethanolamine (PE) to sulfoquinovosyldiacylglycerol (SQDG). Additionally, ETHYLENE RESPONSE FACTOR 10 (StERF10) is identified as a direct transcriptional activator of StGSH1 . BSO‐mediated GSH depletion reduced the LP adaptation in StERF10 ‐OE plants, whereas GSH supplementation rescued StERF10 ‐RNAi plants, indicating StERF10 conferred LP adaptation largely through StGSH1 ‐mediated GSH biosynthesis. Collectively, these findings establish the StERF10‐StGSH1 module as a critical nexus connecting GSH biosynthesis to LP adaptation, providing a rational target for breeding varieties with enhanced phosphorus use efficiency.