The plant epidermis, despite being a single-cell layer, serves diverse roles in regulating organ growth, responding to environmental cues, and mediating gas exchange and water loss. While extensive research has focused on epidermal differentiation in leaves, where stomata and trichomes play critical roles in overall plant physiology, much less is known about epidermal cell fate on fruit surfaces. Many developing fruits initially contain stomata, but as the fruit rapidly expands, these structures face mechanical strain and often rupture. In several species, this process leads to the formation of lenticels, small, permanently open pores that enable continued gas exchange. While lenticels are essential for gas exchange in certain fruit, their presence and morphologies vary widely across species, and the underlying genetic and developmental mechanisms involved in their formation remain poorly understood. Muscadine, a grape species native to the southeastern U.S., serves as a valuable model for studying lenticel development due to its prominent lenticel formation. In this study, we investigated the cellular transition from stomata to lenticels in muscadine fruit using light and electron microscopy, revealing key stages in epidermal restructuring. Transcriptomic analysis of one muscadine cultivar across four developmental stages of lenticel formation identified candidate genes that may regulate this process. These findings provide insight into the genetic regulation of lenticel development that can help explain natural variation in lenticel traits observed across different muscadine cultivars and fruit species. Further, by drawing comparisons to periderm formation in woody tissues and wound responses in other fruit, this study highlights potential conserved genetic pathways underlying lenticel development. Understanding these processes can provide insights into the role of lenticels in postharvest physiology and contribute to targeted breeding strategies for improving fruit storability.
