Functional diversification of class1 KNOX genes in basal eudicots

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KNOX genes are a family of homeobox genes that are essential regulators of plant shoot development. KNOX genes are required for continued growth of the shoot apical meristem, and leaf formation requires KNOX genes to be downregulated. In several angiosperm lineages, an additional function of KNOX genes in the control of leaf dissection has evolved. However, evolutionary changes of KNOX gene action associated with modifications of leaf forms are not well understood. This project aims to characterize this small gene family and its role in leaf development in the basal eudicot plant Eschscholzia californica. Eschscholzia provides a unique system because of its dissected leaves, its phylogenetic position between core eudicots and basal angiosperms, and the availability of developmental genetic technologies. In addition, contrasting developmental patterns in related species invite within-family comparisons. To understand dissected leaf development, we will firstly characterize the class 1 KNOX genes and their expression patterns in Eschscholzia and the related genus Chelidonium. Secondly, phenotypic effects of modulated expression will be determined in Eschscholzia, using Agrobacterium-mediated transformation and Virus-induced gene silencing. To further assess differences in the action of KNOX genes between Eschscholzia and other species, and between dissected and simple leaves, the interaction with other genes and with phytohormones will be studied. Comparisons with other species will promote our understanding of how diversification of KNOX genes is implicated in morphological evolution.