title: An Epigenetic Role for Disrupted Paternal Gene Expression in Postzygotic Seed Abortion in Arabidopsis Interspecific Hybrids.
abstract: Interspecific hybrids often increase the levels of heterozygosity and hybrid vigor, but some interspecific hybrid seeds are aborted shortly after fertilization. The mechanism behind this postzygotic seed abortion is poorly understood. Here, we report genome-wide analysis of allelic expression changes in developing siliques and seeds in three F1 interspecific crosses between Arabidopsis thaliana (Col, Ler, or C24) and Arabidopsis arenosa. The majority of maternally expressed genes (MEGs) were shared among all three F1 interspecific crosses, whereas ∼90% of 272 paternally expressed genes (PEGs) were found only in one or two F1 crosses, suggesting a role for disrupted paternal gene expression in seed abortion that varies in different crosses. Consistent with this notion, 12 PEGs in the infertile interspecific hybrids matched MEGs in fertile intraspecific hybrids. This disruption of PEGs in the interspecific hybrids was consistent with the upregulation of the genes in the paternal-excess interploidy cross (2X6) between a diploid mother and a hexaploid father, leading to the seed abortion. Moreover, a subset of PEGs in the interspecific crosses were also upregulated in the intraspecific hybrid met1XWT or meaXWT, in which the mutant of MET1 (DNA METHYLTRANSFERASE1) or MEDEA, a Polycomb Repressive Complex2 gene, was used as the maternal parent. These data suggest that maternal epigenetic factors and paternal gene expression play important roles in the postzygotic seed abortion in interspecific hybrids or neo-allopolyploids.
authors.affiliation: Department of Molecular Biosciences, Center for Computational Biology and Bioinformatics, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Kirkbride
authors.affiliation: Department of Molecular Biosciences, Center for Computational Biology and Bioinformatics, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Helen Hong
authors.initials: HH
authors.lastname: Yu
authors.affiliation: Department of Molecular Biosciences, Center for Computational Biology and Bioinformatics, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Gyoungju
authors.initials: G
authors.lastname: Nah
authors.affiliation: Department of Molecular Biosciences, Center for Computational Biology and Bioinformatics, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Changqing
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Molecular Biosciences, Center for Computational Biology and Bioinformatics, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Shi
authors.affiliation: Department of Molecular Biosciences, Center for Computational Biology and Bioinformatics, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA. Electronic address: zjchen@austin.utexas.edu.
authors.forename: Z Jeffrey
authors.initials: ZJ
authors.lastname: Chen
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D004171:Diploidy; D057890:Epigenomics; D018506:Gene Expression Regulation, Plant; D055993:Germ Cells, Plant / Q000378:metabolism; D006824:Hybridization, Genetic; D012639:Seeds / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D013045:Species Specificity
chemical_list: D029681:Arabidopsis Proteins
keywords: epigenetics; hybrid incompatibility; imprinting; paternal gene expression; polyploidy; seed development