title: Architecture of floral branch systems in maize and related grasses.
abstract: The external appearance of flowering plants is determined to a large extent by the forms of flower-bearing branch systems, known as inflorescences, and their position in the overall structure of the plant. Branches and branching patterns are produced by tissues called shoot apical meristems. Thus, inflorescence architecture reflects meristem number, arrangement and activity, and the duration of meristem activity correlates with branch length. The inflorescences of maize, unlike those of related grasses such as rice and sorghum, predominantly lack long branches, giving rise to the tassel and familiar corncob. Here we report the isolation of the maize ramosa1 gene and show that it controls inflorescence architecture. Through its expression in a boundary domain near the nascent meristem base, ramosa1 imposes short branch identity as branch meristems are initiated. A second gene, ramosa2, acts through ramosa1 by regulating ramosa1 gene expression levels. ramosa1 encodes a transcription factor that appears to be absent in rice, is heterochronically expressed in sorghum, and may have played an important role in maize domestication and grass evolution.
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Vollbrecht
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Springer
authors.forename: Lindee
authors.initials: L
authors.lastname: Goh
authors.forename: Edward S
authors.initials: ES
authors.lastname: Buckler
authors.forename: Robert
authors.initials: R
authors.lastname: Martienssen
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D035264:Flowers / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D010641:Phenotype; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006109:Poaceae / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D003313:Zea mays / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D018749:RNA, Plant; D014157:Transcription Factors