title: The influence of B chromosomes on rDNA organization in rye interphase nuclei.
abstract: Patterns of rye rDNA organization in interphase nuclei were studied through the use of in situ hybridization in spreads of root meristem cells from plants with and without B chromosomes (Bs). In cells from plants without Bs each rDNA locus is organized as a single perinucleolar knob of condensed chromatin with decondensed chromatin inside the nucleolus. In plants with Bs there is a marked modification of the pattern, found in more than 23% of nuclei, which involves several regions of condensed chromatin interspersed with decondensed chromatin inside the nucleolus. This B-induced alteration in rDNA interphase organization suggests a change in expression of the rRNA genes located on the A chromosomes probably related to the reduction in nuclear RNA observed previously in plants with Bs. The influence of the Bs on the expression of A chromosome genes, through rearrangement of interphase chromatin, could provide the basis of an explanation for some of the known phenotypic effects of B chromosomes in rye.
authors.affiliation: Departamento de Botânica e Engenharia Biológia, Instituto Superior de Agronomia, Lisboa, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Delgado
authors.forename: L
authors.initials: L
authors.lastname: Morais-Cecílio
authors.forename: N
authors.initials: N
authors.lastname: Neves
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
authors.forename: W
authors.initials: W
authors.lastname: Viegas
mesh_terms: D002467:Cell Nucleus / Q000648:ultrastructure*; D002875:Chromosomes / Q000648:ultrastructure*; D018744:DNA, Plant / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase; D008677:Metaphase; D018517:Plant Roots / Q000648:ultrastructure; D012434:Secale / Q000235:genetics* / Q000648:ultrastructure
chemical_list: D018744:DNA, Plant; D004275:DNA, Ribosomal