Molecular and genetic characterization of floral regulatory networks in maize

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What causes plants to flower? Plant biologists have been trying to answer this question for nearly a century but, until recently, the nature of the signals that cause plants to flower remained a mystery. One important discovery of early research is that flowering signals are produced in the leaves and then transported a long distance to the central shoot of the plant, where the actual flowers are made. My research addresses this question with the modern tools of molecular biology, biochemistry and genomics. The focus of our research is gene from corn (maize) that is critically important for flowering. Maize plants with a normal copy of this gene, called INDETERMINATE1 or ID1, flower at the usual time, whereas mutant maize plants with a defective ID1 gene flower very late and produce flowers with leafy characteristics. We cloned the ID1 gene and characterized it using molecular genetic techniques. The DNA sequence suggests that ID1 acts by making a protein, called a zinc finger, which is a master regulator of other genes. In other words, ID1 causes flowering in corn by turning other genes 'on' or 'off'. This in turn will affect how the plant grows and responds to its environment. There are two main goals of this proposal: 1) to identify genes that are controlled by the ID1 gene, and 2) to identify other proteins that physically interact with the ID1 protein help it carry out its function. Knowing this will give clues about the changes that go on in the plant when flowering is about to occur. Ultimately we would like to identify the biochemical components of these signals, to understand the metabolic changes that affect the flowering process, and to understand how plants interpret environmental signals to flower at the correct time. Discovering how ID1 works will lead to a better understanding of how all plants control their flowering habits. The ability to control when, or if, a plant flowers is of vital importance to agriculture because plants coordinate flowering for optimal seed and fruit production. Determining how plants like maize, and its relatives such as rice, wheat and sugar cane, control flowering will help to improve the productivity of these vital crop plants.