REGULATION OF LEAF INITIATION BY THE TERMINAL EAR-1 GENE OF MAIZE

Higher plants elaborate much of their architecture post-embryonically through development initiated at the tips of shoots(1,2) During vegeta tive growth, leaf primordia arise at predictable sires to give charact eristic leaf arrangements, or phyllotaxies(3,4). How these sites are d etermined is a long-standing question(5,6) that bears on the nature of pattern-formation mechanisms in plants, Fate-mapping studies in sever al species indicate that each leaf primordium becomes organized from a group of 100-200 cells on the flank of the shoot apes'. Although mole cular studies indicate that the regulated expression of specific homeo box genes plays some part in this determination process(8-11), mechani sms that regulate the timing and position of leaf initiation are less well understood. Here we describe a gene from maize, terminal ear 1. P atterns of expression of this gene in the shoot and phenotypes of muta nts indicate a role for terminal ear 1 in regulating leaf initiation. The te1 gene product contains conserved RNA-binding motifs, indicating that it may function through an RNA-binding activity.