Developmental diversity in meristem organization: lessons from non-canonical plant body plans for biotechnology

The canonical plant bauplan is governed by the activity of the shoot apical meristem (SAM), a structural hub established during embryogenesis that produces repeating modular units known as phytomers. However, extreme morphological divergence in families such as Podostemaceae, Lemnaceae, and Gesneriaceae reveals the plasticity of plant developmental programs. In several lineages, the canonical deployment of meristematic programs is modified, displaced, or developmentally reduced, giving rise to divergent but evolutionarily successful body plans. This review explores the molecular interplay of meristematic regulators, characterizes the growth habits and genomic landscapes of these non-canonical lineages, and discusses how they may inform experimentally testable frameworks for engineering next-generation crop architectures.