More Than Skin Deep: Native Periderm Development and Lignin-mediated Durability in Sweetpotato Storage Roots

Abstract

The sweetpotato native periderm is a critical protective tissue that replaces the epidermis during secondary growth in storage roots and plays a central role in determining postharvest quality and marketability. Damage to this tissue during harvest increases water loss and susceptibility to pathogen infection, necessitating postharvest curing to induce wound periderm formation. Although wound periderm development has been extensively characterized, particularly in model systems, the formation and regulation of native periderm remain comparatively underexplored. This imbalance limits the translation of mechanistic insights from wound healing to strategies to improve the durability of native periderm under diverse production conditions. A key but underexamined factor contributing to this gap is lignification. Lignin deposition has been largely interpreted in the context of wound responses, where it is viewed as a terminal structural outcome, thus potentially obscuring its broader role in the development of native periderm. As a result, the contribution of lignification to variations in native periderm structure and function remains unresolved. This review synthesizes the current understanding of native periderm formation in sweetpotato by drawing on model and well-characterized species and repositions lignin and lignification as important contributors to native periderm development. By integrating developmental and applied perspectives, this work identifies key knowledge gaps and provides a framework to improve the durability of native periderm, storage root quality, and crop resilience. These insights position lignification as a tractable target for improving sweetpotato skin quality across diverse production systems.