Deciphering Maize Floral Regulatory Networks

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For nearly a century plant biologists have been trying to decipher the mechanisms that control flowering time in plants. Until recently the nature of the signals that cause plants to flower remained a complete mystery. Early researchers discovered that a flower-inducing substance is synthesized in leaves and then transported a long distance to the central shoot of the plant to a region of stem cells where the actual flowers are made. My research uses the tools of molecular biology, biochemistry and genomics to better understand the nature of the flowering process. Our research revolves around the study of the maize INDETERMINATE1 gene, or ID1, which is critically important for flowering. Maize plants with a normal copy of this gene flower at the usual time, whereas maize with a mutated ID1 gene flowers very late and produces defective flowers. We isolated the ID1 gene and characterized it using molecular techniques. ID1 encodes a zinc finger transcription factor protein that acts in leaves as a master regulator of other genes, suggesting that ID1 causes flowering in maize by turning other genes 'on' or 'off' and controlling a the long distance leaf signal. There are three main goals of this proposal: 1) to characterize the molecular, biochemical and physiological components in plants that make up the leaf signals that specify time to flower; 2) to identify genes that are controlled by the ID1 gene, and 3) to work out the basic molecular mechanisms, as typified by studying ID1 activity, used by higher organisms to regulate gene function. Ultimately we would like to identify the biochemical components and metabolic changes that affect the flowering process. Moreover, we will better understand how plants interpret environmental signals so that they flower at the correct time. Discovering how ID1 controls flowering time could lead to a better understanding of flowering in maize as well its agriculturally important relatives such as wheat rice, sorghum, sugarcane and various 'energy grasses' such as Miscanthus. The ability to control time to flowering is of vital importance to agriculture because plants coordinate flowering for optimal seed and fruit production. Therefore understanding flowering will help to improve the productivity of vital crop plants.