02718naa a2200313 a 450000100080000000500110000800800410001902400520006010000180011224501130013026000090024352018050025265000150205765000160207265300130208865300180210165300190211965300230213865300120216165300240217370000190219770000230221670000190223970000160225870000230227470000260229770000180232377300630234121334952021-08-12       2020    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1007/s11105-020-01203-42DOI1 aSANTOS, Y. D.  aEpigenetic marks associated to the study of nucleolar dominance in Urochloa P. Beauv.h[electronic resource]  c2020  aThe genus Urochloa P. Beauv. presents a prominent role in the tropical agricultural scenario being composed of species with different ploidy levels. Studies on the genomic relationship within this genus as well as specific analysis involving epigenetic marks are limited. The aim of the present study was to identify the cytosine methylation (5-mCyt) and histone H3 lysine 9 dimethylation (H3k9me2) in the different modulations of 45S ribosomal DNA (rDNA) sites in interphase nuclei and to associate these results with gene expression analysis in Urochloa ruziziensis (2n = 4x = 36), Urochloa brizantha cv. Marandu (2n = 4x = 36), and their respective interspecific hybrid H1863 (2n = 4x = 36). Immunolocalization techniques were performed in combination with Fluorescence in situ hybridization (FISH) for the location of the 45S rDNA sites. Predominantly, we observed intraand perinucleolar sites, mostly hypomethylated and/or hyper/hypomethylated, decondensed or partially condensed. The gene expression analysis was performed qualitatively through the conventional PCR using complementary DNA and confirmed by the RT-qPCR technique and primers designed for the ITS-1 region of U. brizantha and U. ruziziensis. The molecular analyses performed on leaves showed that there is dominance of U. brizantha 45S rDNA gene expression on U. ruziziensis in the H1863 hybrid. In roots, the analyses showed that the 45S rDNA genes of the two parents are expressed in the hybrid genome. Thus, it is plausible to infer a tissue-specific nuclear dominance model in which the pattern of hypermethylated cytosine sites with heterochromatic marks and, therefore, silenced were mostly inherited from U. ruziziensis, whereas the rDNA originated from U. brizantha was characterized by cytosine and H3k9 hypomethylation.  aBrachiaria  aMetilação  aCitosina  aDimetilação  aDNA ribossomal  aExpressão gênica  aHistona  aNucleolar dominance1 aPEREIRA, W. A.1 aPAULA, C. M. P. de1 aRUME, G. de C.1 aLIMA, A. A.1 aCHALFUN-JUNIOR, A.1 aSOUZA SOBRINHO, F. de1 aTECHIO, V. H.  tPlant Molecular Biology Reportergv. 38, p. 380-393, 2020.