title: Analysis of four embryo-specific mutants in Zea mays reveals that incomplete radial organization of the proembryo interferes with subsequent development.
abstract: Using confocal laser scanning microscopy we have characterized early and intermediate stages of maize wild-type embryogenesis and compared to mutant development of four different embryo-specific mutations, emb*-8518, emb*-8521, emb*-8537, and emb*-8542. Confocal laser scanning microscopy is well suited to study embryo development in maize in a nondisruptive manner from shortly after fertilization to late stages in embryogenesis. The analysis of the mutant morphology indicated that two of the recessive mutations, emb*-8518 and emb*-8521, cause an early developmental arrest in the proembryo/early transition stage: mutant embryos are unable to enter the morphogenetic phase of embryogenesis. In contrast, homozygous emb*-8537, and emb*-8542 embryos progress at least to the coleoptilar stage and sometimes establish a functional shoot meristem that can determine leaf primordia. The morphological characterization of mutants was confirmed by analysis of the expression pattern of three different marker genes: Lipid transfer protein 2, Zea mays Outer Cell Layer 1, and Knotted 1. Our data indicate that both emb*-8518 and emb*-8521 mutant embryos are impaired in restriction of ZmOCL1 transcripts to the embryonic protoderm and therefore fail to establish a normal radial organization. In contrast, emb*-8537 and emb*-8542 embryos exhibit the wild-type pattern and proceed in development to the formation of a shoot apical meristem and the establishment of bilateral symmetry.
authors.affiliation: Institut für Entwicklungsbiologie, Universität zu Köln, 50923 Cologne, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Elster
authors.forename: P
authors.initials: P
authors.lastname: Bommert
authors.forename: W F
authors.initials: WF
authors.lastname: Sheridan
authors.forename: W
authors.initials: W
authors.lastname: Werr
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D006720:Homozygote; D009154:Mutation; D010641:Phenotype; D012639:Seeds / Q000254:growth & development* / Q000378:metabolism; D003313:Zea mays / Q000235:genetics*
chemical_list: D017931:DNA Primers