Molecular Mechanism of EMF1-Mediated Floral Repression in Arabidopsis

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

0236399 Sung The EMBRYONIC FLOWER (EMF) genes, EMF1 and EMF2, are required for vegetative development and involved in reproductive development. Fourteen loss-of-function mutants were isolated and most were characterized in our laboratory. The mutants flower upon germination and modulation of EMF activities generated fertile plants that flower early and plants that show altered inflorescence architecture. Cloning the EMF genes revealed that EMF1 encodes a putative transcriptional regulator and EMF2 a Polycomb Group (PcG) protein homolog. Gene expression studies suggest that EMF proteins exert global repression of the flower and seed program, thereby allowing vegetative development upon germination. The proposed research aims to investigate the molecular mechanism of EMF1-mediated floral repression. The long-term goal of the proposed research is to elucidate the epigenetic mechanism underlying plant development. The objectives are to further characterize the function of EMF1 and several proteins that interact with EMF1, and identify the target genes of EMF1. Immunological or tagged-protein detection will be employed to study possible posttranscriptional regulation of EMF1 and develop tools for EMF1 protein detection and isolation. The regions of EMF1 responsible for protein-protein interaction with the EMF1-interacting proteins will be characterized. An inducible system will be used to activate EMF1 in emf1 mutants and identify early targets of EMF1. Finding a protein complex that inactivates the floral organ identity or other early target genes will provide insights into the mechanism of floral repression during vegetative development. Understanding of the molecular mechanism of EMF1-mediated floral repression would enable the design of crops that flower at specific time, thereby increasing the geographical range of their cultivation. A postdoctoral fellow and a graduate student will be involved in the proposed research. While the postdoctoral fellow has the necessary skills to carry out most of the experiments proposed, he will also learn new concepts and techniques during the course of the proposed research. The graduate student will be trained in a variety of molecular and immunological techniques. Both will be involved in the design of the experiments and articulation of experimental findings through oral and written presentations. Typically, undergraduate students of diverse backgrounds are involved in our research projects. Underrepresented students have access to our research projects through the campus-wide Summer Research Opportunity Programs and Undergraduate Research Opportunity Programs.