Expression of 1R rDNA loci in Triticale: Genetic and Developmental Controls
1996; Springer Nature (Netherlands); Linguagem: Inglês
10.1007/978-94-009-0329-6_14
ISSN1381-673X
AutoresWanda Viegas, Manuela Silva, Nuno Neves, Alexandra Castilho, Augusta Barão, Álvaro Antônio Alencar de Queiroz, J. S. Heslop‐Harrison, Leonor Morais‐Cecílio, Luis Amado, Margarida Delgado, Vitor Carvalho,
Tópico(s)Plant Disease Resistance and Genetics
ResumoUsing the silver staining technique, which allows the identification in metaphase cells of rDNA loci active in the previous interphase, it was observed the consistent expression of 1R NOR in hexaploid triticale cultivars with a 2R/2D chromosome substitution, confirmed through genomic in situ hybridization using rye total genomic DNA and different cloned probes of repetitive sequences. A control mediated by non-nucleolar chromosomes on the suppression of rye NOR in triticale was therefore detected since it was possible to observe the expression of those loci in the presence of all wheat major NORs. It was also established that the 1R NOR expression pattern in complete hexaploid triticale cultivars is a developmental-dependent process, since: (i) the epigenetic pattern of IR NOR inactivation in the presence of wheat genomes is syncronously established in embryos and endosperms between the 4th and the 5th day after fertilization; (ii) the influence of induced DNA demethylation on that pattern, through the incorporation of 5-azacytidine, is also dependent on the seed developmental stage; and (iii) the rye NOR suppression pattern is maintained until meiosis being erased during this process.
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