Genome-dependent chromosome dynamics in three successive generations of the allotetraploid Festuca pratensis × Lolium perenne hybrid

Abstract

We focus on the identification of complete and recombined ribosomal DNA-bearing chromosomes, and the dynamics of chromosomal number and position of ribosomal DNA (rDNA) loci in the F2-F4 generations derived from the F1 hybrid of Festuca pratensis Huds. (2n = 4x = 28) × Lolium perenne L. (2n = 4x = 28). Lolium genomic DNA and rRNA genes were mapped by means of genomic and fluorescence in situ hybridization (GISH and FISH). The results revealed that plants of the three generations share various rDNA loci profiles with chromosome structural changes, possibly as a result of chromosomal inter- and intra-rearrangements. We observed an asymmetrical variation in the number of recombinant arms with and without rDNA loci between parental genomes. The Lolium genome was more affected by rearrangements in arms with rDNA loci, while Festuca was more affected in arms without them. Statistically significant differences between L. perenne and F. pratensis genomes concerned the number of recombined chromosomes without rDNA, and the number of recombined rDNA-bearing chromosomal arms of marked chromosomes, showing a tendency of F. pratensis genome-like chromosomes to be less stable, compared with L. perenne. We postulate a novel genome-dependent range and type of chromosome variation in plants of the F2-F4 generations derived from F. pratensis × L. perenne hybrid.Electronic supplementary materialThe online version of this article (doi:10.1007/s00709-014-0734-9) contains supplementary material, which is available to authorized users.

Karyotype reshufflings of Festuca pratensis × Lolium perenne hybrids

“…However, Zwierzykowski et al ( 2006 ) reported that in the F 2 -F 6 progeny of the F. pratensis × L. perenne hybrid, chromosomes of Festuca were more frequently recombined. Książczyk et al ( 2015 ) on the basis of the analysis of F 2 -F 4 generations of the F. pratensis × L. perenne hybrid suggested an asymmetrical variation of parental genomes and higher predisposition of Festuca chromosome to structural rearrangements. Despite a low number of plants in each generation, we also observed that the chromosomes of F. pratensis were more recombined, although their number was decreasing in successive generations.…”

“…GISH with total genomic DNA as a probe can discriminate parental genomes in hybrids and can reveal the occurrence of intergenomic rearrangements (Kopecký et al 2006 ). The combination of FISH and GISH techniques has been effectively used for detecting genome compositions and variation in various plant species (Dou et al 2009 ; Kwiatek et al 2016 ; Majka et al 2016 ), including Festuca and Lolium hybrids (Kosmala et al 2006 ; Książczyk et al 2015 ).…”

The chromosomal constitution of fish hybrid lineage revealed by 5S rDNA FISH

“…Modern cytogenetic analyses, such as FISH and GISH have been widely applied for studies in many processes of chromosome evolution, including structural rearrangements, as well as extensive studies on phylogenetic and genomic relationships [ 31 ]. In this work, chromosome inheritance of hybrid lineage progenies of RCC × CC were investigated by detecting the signal of 340 bp fragments of 5 s rDNA on chromosomes in successive generations, i.e.…”

“…The chromosomal rearrangements having occurred less frequently was a promising result supporting the development of stable allotetraploid hybrid lines, which were also proved in allohexaploid Brassica line [ 34 ] and the lineage of X.laevis [ 35 ]. However, the allotetraploid Festuca pratensis × Lolium perenne hybrid of three generations shared various rDNA loci profiles with chromosomal rearrangements [ 31 ], indicating a tendency of F. pratensis genome-like chromosomes to be less stable in hybrid of three generations. In our work, the strong FISH signals of 5S rDNA in RCC passed down stably in successive hybrid generation, which implied that chromosomal rearrangements have occurred less frequently in area of highly repeated sequence of 5S rDNA.…”

Genomic Constitution and Relationship in Urochloa (Poaceae) Species and Hybrids

“…Molecular cytogenetic analyses, such as fluorescent in situ hybridization (FISH) and genomic in situ hybridization (GISH), have been widely used to assist with differentiation of plant genomes (Zwierzykowski et al, 2008;Wolny et al, 2011), to solve some uncertainties about chromosome evolution processes that include structural rearrangements (Kopecký et al, 2006;Książczyk et al, 2014), and to infer phylogenetic and genomic relationships (Kopecký et al, 2006;Reis et al, 2014). Genomic in situ hybridization provides visual and straightforward results on genomic composition and relationships among species.…”