Mechanism of the Unifacial Leaf Development and Evolution in Juncus

Abstract

Unifacial leaf, in which leaf surface consists only of the abaxial side, has been evolved in a number of divergent species in monocots. The unifacial leaves provide very unique opportunities for the developmental studies of the leaf axes formation in monocots. In addition, the mechanism of the parallel evolution of such drastic changes in leaf polarities is of interest from an evolutionary viewpoint.
We are studying molecular genetic mechanisms of the unifacial leaf development and their evolution, mainly using Juncus as a model system, which is very suitable for molecular genetic studies. In addition, Juncus are known for a wide variety of leaf forms. We carried out developmental and gene expression analyses in Juncus, and combined their results with phylogeny of Juncus species. As a result, we revealed the evolutionary patterns of unifacial leaves in Juncus, and illustrated key regulatory changes of gene expressions for the unifacial leaf development.