The secrets of variegated leaves: Molecular to physiological and ecological insights

Abstract

Leaf variegation, characterized by multicolored patterns such as white, yellow, red, or purple hues, deviates from the uniform green coloration typical of most plants due to complex genetic, physiological, and structural mechanisms. It can arise from stable genetic mutations or transient environmental influences and is broadly classified into structural and pigment-based types. Mechanistically, variegation is further divided into four categories based on chlorophyll absence, internal air spaces, epidermal structure, or localized pigment expression. Genetic studies in model species such as Arabidopsis thaliana, tobacco, rice, and tomato have revealed that mutations affecting chloroplast biogenesis and pigment biosynthesis often underlie variegated phenotypes. In addition to its ornamental appeal, variegation plays critical physiological and ecological roles, influencing photosynthesis, photoprotection, thermoregulation, and plant-herbivore interactions. Pseudo-variegation, a visually similar but a non-genetic phenomenon induced by other organisms, can also confer adaptive advantages such as herbivore deterrence and environmental stress tolerance. Recent research highlights the importance of integrating molecular, anatomical, and ecological perspectives to fully understand the developmental and adaptive significance of leaf variegation in higher plants.