delayed flowering1 Encodes a Basic Leucine Zipper Protein That Mediates Floral Inductive Signals at the Shoot Apex in Maize (original) (raw)

1 2 Separation of the life cycle of flowering plants into two distinct growth phases, 3 vegetative and reproductive, is marked by the floral transition. The initial floral 4 inductive signals are perceived in the leaves and transmitted to the shoot apex, 5 where the vegetative shoot apical meristem (SAM) is restructured into a 6 reproductive meristem. In this study, we report cloning and characterization of 7 the maize (Zea mays L.) flowering time gene, delayed flowering1 (dlf1). Loss of 8 dlf1 function results in late flowering, indicating dlf1 is required for timely 9 promotion of the floral transition. dlf1 encodes a protein with a basic leucine 10 zipper (bZIP) domain belonging to an evolutionarily conserved family. Three 11 dimensional (3D) protein modeling of a missense mutation within the basic 12 domain suggests DLF1 protein functions through DNA binding. The spatial and 13 temporal expression pattern of dlf1 indicates a threshold level of dlf1 is required 14 in the shoot apex for proper timing of the floral transition. Double mutant analysis 15 of dlf1 and indeterminate1 (id1), another late flowering mutation, places dlf1 16 downstream of id1 function and suggests dlf1 mediates floral inductive signals 17 transmitted from leaves to the shoot apex. This study establishes an emergent 18 framework for the genetic control of floral induction in maize, and highlights the 19 conserved topology of the floral transition network in flowering plants. 20 21 22 www.plant.org on December 5, 2015 -Published by www.plantphysiol.org Downloaded from