A BoVIT1-Mediated Molecular Hub Orchestrates Anthocyanins Based Pigmentation in Red-Stalked Chinese Kale
In plants, the stabilization of anthocyanins (ACNs) through metal coordination, particularly with iron (Fe), is a critical, tightly regulated mechanism. This process involves vacuolar iron transporter (VIT) proteins, which sequester excess iron into vacuoles to prevent cytotoxicity. Additionally, VITs are implicated in the blue pigmentation of petals in certain flowers, yet the precise mechanism by which VITs influence ACN-based pigmentation remains poorly understood.In this study, ACNs accumulation in red-stalked Chinese kale is governed by a metalloflavonoid network that integrates iron homeostasis with metabolic flux. Multi-omics analyses identified BoVIT1 as a key regulatory component, closely associated with pivotal flavonoid biosynthesis genes, including the canonical MYB-bHLH-WD40 (MBW) complex. Functional validation revealed that silencing BoVIT1 reduces ACNs content, whereas its overexpression enhances ACNs accumulation, positioning BoVIT1 as a metabolic rheostat balancing iron availability and ACNs stability. Moreover, the transcriptional coordination of BoVIT1 and BoANS1 (encoding anthocyanidin synthase) is fine-tuned by the MBW complex through a shared cis-regulatory motif within their promoters.Our findings unveil a novel role for VIT proteins in plant pigmentation, extending their conventional function in metal sequestration and providing a mechanistic framework for understanding the interplay between metal availability and pigmentation.