Interpopulation hybridization generates meiotically stable rDNA epigenetic variants in allotetraploid Tragopogon mirus

0457675 - BFÚ 2016 RIV GB eng J - Journal Article
Matyášek, Roman - Dobešová, Eva - Húska, Dalibor - Ježková, Ivana - Soltis, P. S. - Soltis, D.E. - Kovařík, Aleš
Interpopulation hybridization generates meiotically stable rDNA epigenetic variants in allotetraploid Tragopogon mirus.
Plant Journal. Roč. 85, č. 3 (2016), s. 362-377. ISSN 0960-7412. E-ISSN 1365-313X
R&D Projects: GA ČR(CZ) GA14-34632S; GA ČR GBP501/12/G090; GA ČR(CZ) GA13-10057S
Institutional support: RVO:68081707
Keywords : allopolyploid * chromatin modification * epigenetic variants
Subject RIV: BO - Biophysics
Impact factor: 5.901, year: 2016

Uniparental silencing of 35S rRNA genes (rDNA), known as nucleolar dominance (ND), is common in interspecific hybrids. Allotetraploid Tragopogon mirus composed of Tragopogon dubius (d) and Tragopogon porrifolius (p) genomes shows highly variable ND. To examine the molecular basis of such variation, we studied the genetic and epigenetic features of rDNA homeologs in several lines derived from recently and independently formed natural populations. Inbred lines derived from T. mirus with a dominant d-rDNA homeolog transmitted this expression pattern over generations, which may explain why it is prevalent among natural populations. In contrast, lines derived from the p-rDNA dominant progenitor were meiotically unstable, frequently switching to co-dominance. Interpopulation crosses between progenitors displaying reciprocal ND resulted in d-rDNA dominance, indicating immediate suppression of p-homeologs in F-1 hybrids. Original p-rDNA dominance was not restored in later generations, even in those segregants that inherited the corresponding parental rDNA genotype, thus indicating the generation of additional p-rDNA and d-rDNA epigenetic variants.
Permanent Link: http://hdl.handle.net/11104/0258048