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First published online October 27, 2006; 10.1104/pp.106.088815 Plant Physiology 142:1523-1536 (2006) © 2006 American Society of Plant Biologists delayed flowering1 Encodes a Basic Leucine Zipper Protein That Mediates Floral Inductive Signals at the Shoot Apex in Maize[W]Pioneer Hi-Bred International Incorporated, Johnston, Iowa 50131 (M.G.M., D.M.S., Z.H., E.B., R.A., E.V.A., O.N.D.); and DuPont Crop Genetics Research, Experimental Station, Wilmington, Delaware 198800353 (T.D., B.L.)
Separation of the life cycle of flowering plants into two distinct growth phases, vegetative and reproductive, is marked by the floral transition. The initial floral inductive signals are perceived in the leaves and transmitted to the shoot apex, where the vegetative shoot apical meristem is restructured into a reproductive meristem. In this study, we report cloning and characterization of the maize (Zea mays) flowering time gene delayed flowering1 (dlf1). Loss of dlf1 function results in late flowering, indicating dlf1 is required for timely promotion of the floral transition. dlf1 encodes a protein with a basic leucine zipper domain belonging to an evolutionarily conserved family. Three-dimensional protein modeling of a missense mutation within the basic domain suggests DLF1 protein functions through DNA binding. The spatial and temporal expression pattern of dlf1 indicates a threshold level of dlf1 is required in the shoot apex for proper timing of the floral transition. Double mutant analysis of dlf1 and indeterminate1 (id1), another late flowering mutation, places dlf1 downstream of id1 function and suggests dlf1 mediates floral inductive signals transmitted from leaves to the shoot apex. This study establishes an emergent framework for the genetic control of floral induction in maize and highlights the conserved topology of the floral transition network in flowering plants.
1 Present address: Syngenta Seeds, 2369 330th St., Slater, IA 50244. 2 Present address: Iowa State University College of Veterinary Medicine, Iowa State University, Ames, IA 50011. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Olga N. Danilevskaya (olga.danilevskaya{at}pioneer.com). [W] The online version of this article contains Web-only data. www.plantphysiol.org/cgi/doi/10.1104/pp.106.088815 * Corresponding author; e-mail olga.danilevskaya{at}pioneer.com; fax 5153344788. Received August 24, 2006; accepted October 21, 2006; published October 27, 2006. This article has been cited by other articles:
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