Transcription factor StbZIP10 positively regulates zinc uptake and transport in potato.

Abstract

Zinc deficiency represents a major micronutrient constraint in potato (Solanum tuberosum L.) production, frequently resulting in growth retardation and substantial yield loss. Although zinc is essential for plant development, the molecular mechanisms underlying potato responses to zinc deficiency remain poorly understood. While bZIP transcription factors are known to play important roles in plant adaptation to zinc stress, their specific regulatory networks are not fully resolved. Here, we systematically investigated the function of StbZIP10 in zinc homeostasis through genetic transformation and zinc content analysis in transgenic potato lines. Our findings demonstrate that StbZIP10 interacts with the calmodulin-like protein StCML13 to form a functional dimer. This interaction enhances the binding affinity of StbZIP10 to the promoter of the downstream target gene StZIP2, thereby activating its transcription and promoting zinc uptake and transport, which ultimately improves potato tolerance to zinc deficiency. Collectively, this study reveals a key regulatory module consisting of StbZIP10 and StCML13 in the potato zinc deficiency response and provides new molecular insights into the regulatory network of zinc homeostasis in plants.