The transition of shoot apical meristems from vegetative growth to flowering is the major developmental switch in the plant life cycle. It is important because flowering results in the production of the edible portion of most major crops. Plants have evolved multiple pathways to precisely regulate flowering time to maximize reproductive success. These flowering pathways involve mechanisms to monitor both environmental cues and the developmental state of the plant. The proposed work is designed to further the understanding at a molecular level of flowering-time control.
A major focus of this work is to define the genes involved in floral induction in Arabidopsis thaliana. Arabidopsis is quite versatile in its flowering behavior as it maintains photoperiod, vernalization, hormone and developmental (autonomous) flowering pathways. Arabidopsis is normally a facultative long day plant, but single genetic changes can cause Arabidopsis to exhibit the flowering behavior of many other plant species. Thus knowledge of the molecular basis of flowering-time control obtained from Arabidopsis studies can be used to explore the evolution and control of different modes of flowering regulation among higher plants.
One goal is to identify and molecularly clone flowering-time genes and study the function of the protein products. The LD and FPA loci will be emphasized, but genetical analyses will provide other targets such as a flowering suppressor locus and a locus involved in enhancing the role of ethylene in flowering. A second goal is to continue to genetically analyze genes in the flowering pathways to define the players in these pathways as completely as possible. This involves screens for new loci, studies of interactions among genes and characterization of the flowering physiology of mutants and various genetic combinations. A final goal is to explore the relationship between flowering pathways in Arabidopsis and maize by comparative studies of LD homologs in both species.
