A Conserved Molecular Framework for Compound Leaf Development.

Diversity in leaf shape is produced by alterations of the margin: for example, deep dissection leads to leaflet formation and less-pronounced incision results in serrations or lobes. By combining gone silencing and mutant analyses in four distantly related eudicot species, we show that reducing the function of NAMICUC boundary genes (NO APICAL MERISTEM and CUP-SHAPED COTYLEDON) leads to a suppression of all marginal outgrowths and to fewer and fused leaflets. We propose that NAM/CUC genes promote formation of a boundary domain that delimits leaflets. This domain has a dual role promoting leaflet separation locally and leaflet formation at distance. In this manner, boundaries of compound leaves resemble boundaries functioning during animal development. [ABSTRACT FROM AUTHOR]