title: Parent-of-Origin-Effect rough endosperm Mutants in Maize.
abstract: Parent-of-origin-effect loci have non-Mendelian inheritance in which phenotypes are determined by either the maternal or paternal allele alone. In angiosperms, parent-of-origin effects can be caused by loci required for gametophyte development or by imprinted genes needed for seed development. Few parent-of-origin-effect loci have been identified in maize (Zea mays) even though there are a large number of imprinted genes known from transcriptomics. We screened rough endosperm (rgh) mutants for parent-of-origin effects using reciprocal crosses with inbred parents. Six maternal rough endosperm (mre) and three paternal rough endosperm (pre) mutants were identified with three mre loci mapped. When inherited from the female parent, mre/+ seeds reduce grain fill with a rough, etched, or pitted endosperm surface. Pollen transmission of pre mutants results in rgh endosperm as well as embryo lethality. Eight of the mutants had significant distortion from the expected one-to-one ratio for parent-of-origin effects. Linked markers for mre1, mre2, and mre3 indicated that the mutant alleles have no bias in transmission. Histological analysis of mre1, mre2, mre3, and pre*-949 showed altered timing of starch grain accumulation and basal endosperm transfer cell layer (BETL) development. The mre1 locus delays BETL and starchy endosperm development, while mre2 and pre*-949 cause ectopic starchy endosperm differentiation. We conclude that many parent-of-origin effects in maize have incomplete penetrance of kernel phenotypes and that there is a large diversity of endosperm developmental roles for parent-of-origin-effect loci.
authors.affiliation: Horticultural Sciences Department and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611.
authors.forename: Fang
authors.initials: F
authors.lastname: Bai
authors.affiliation: Horticultural Sciences Department and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611.
authors.forename: Mary
authors.initials: M
authors.lastname: Daliberti
authors.affiliation: Horticultural Sciences Department and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Bagadion
authors.affiliation: Biotechnology Research Institute, National Key Facility for Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Miaoyun
authors.initials: M
authors.lastname: Xu
authors.affiliation: Horticultural Sciences Department and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611.
authors.forename: Yubing
authors.initials: Y
authors.lastname: Li
authors.affiliation: Horticultural Sciences Department and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611.
authors.forename: John
authors.initials: J
authors.lastname: Baier
authors.affiliation: Horticultural Sciences Department and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611.
authors.forename: Chi-Wah
authors.initials: CW
authors.lastname: Tseung
authors.affiliation: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305.
authors.forename: Matthew M S
authors.initials: MM
authors.lastname: Evans
authors.affiliation: Horticultural Sciences Department and Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611 settles@ufl.edu.
authors.forename: A Mark
authors.initials: AM
authors.lastname: Settles
mesh_terms: D000483:Alleles; D056625:Endosperm / Q000235:genetics*; D020869:Gene Expression Profiling; D017343:Genes, Plant / Q000235:genetics; D056426:Genetic Loci; D018392:Genomic Imprinting; D009154:Mutation; D010641:Phenotype; D012639:Seeds / Q000235:genetics; D017423:Sequence Analysis, RNA; D003313:Zea mays / Q000235:genetics*
keywords: endosperm; gametophyte; imprinting; parent-of-origin effect; seed