Angiosperm leaves originate from small, seemingly uniform primordia located at the flanks of the shoot apical meristem. Despite this similarity, leaves develop into an extraordinary range of final forms. One instance of this diversity is the distinction between simple leaves, where the blade is undivided, and compound leaves, where the blade is subdivided into distinct units called leaflets. Using single-cell multiomic approaches, we have created a cross-species atlas of leaf development that includes two pairs of independently evolved simple and complex leaf species. This framework enables us to identify conserved and lineage-specific cell states and reconstruct the regulatory logic that underlies leaf complexity. Our data reveal a striking persistence of particular meristematic identities during leaf development in species with complex leaves. This observation suggests that complex leaves often recruit genetic programs from the shoot apex during leaf morphogenesis, while retaining stem cell populations only in the shoot meristems. In parallel, species-specific deployment of morphogenetic modifiers highlights lineage-specific adaptations that influence leaf morphology.

東京大学大学院理学系研究科・生物科学専攻・発生進化研究室