title: Heterosis in early seed development: a comparative study of F1 embryo and endosperm tissues 6 days after fertilization.
abstract: Heterosis specifies the superior performance of heterozygous individuals and although used in plant breeding the underlying molecular mechanisms still remain largely elusive. In this study, we demonstrate the manifestation of heterosis in hybrid maize embryo and endosperm tissue 6 days after fertilization in crosses of several inbred lines. We provide a comparative analysis of heterosis-associated gene expression in these tissues by a combined approach of suppression subtractive hybridization and microarray hybridizations. Non-additive expression pattern indicated a trans-regulatory mechanism to act early after fertilization in hybrid embryo and endosperm although the majority of genes showed mid-parental expression levels in embryo and dosage dependent expression levels in endosperm. The consistent expression pattern within both tissues and both inbred line genotype combinations of genes coding for chromatin related proteins pointed to heterosis-related epigenetic processes. These and genes involved in other biological processes, identified in this study, might provide entry points for the investigation of regulatory networks associated with the specification of heterosis.
authors.affiliation: Biocenter Klein Flottbek, University of Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Jahnke
authors.forename: Barbara
authors.initials: B
authors.lastname: Sarholz
authors.forename: Alexander
authors.initials: A
authors.lastname: Thiemann
authors.forename: Vera
authors.initials: V
authors.lastname: Kühr
authors.forename: José F
authors.initials: JF
authors.lastname: Gutiérrez-Marcos
authors.forename: Hartwig H
authors.initials: HH
authors.lastname: Geiger
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Piepho
authors.forename: Stefan
authors.initials: S
authors.lastname: Scholten
mesh_terms: D005306:Fertilization / Q000235:genetics; D020869:Gene Expression Profiling; D017343:Genes, Plant; D005838:Genotype; D006823:Hybrid Vigor; D006824:Hybridization, Genetic; D009693:Nucleic Acid Hybridization; D012639:Seeds / Q000235:genetics / Q000254:growth & development*; D003313:Zea mays / Q000196:embryology* / Q000235:genetics