Department of Environmental Stress Biology, Institute of Plant Genetics, Polish Academy of Sciences, Poznań, Poland.
Department of Botany and Nature Protection, University of Silesia in Katowice, Katowice, Poland.
BMC Genomics. 2019 May 14;20(1):367. doi: 10.1186/s12864-019-5766-2.
Species of the Festuca and Lolium genera, as well as intergeneric Festuca × Lolium (Festulolium) hybrids, are valuable fodder and turf grasses for agricultural and amenity purposes worldwide. Festulolium hybrids can merge in their genomes agronomically important characteristics. However, in polyploid plants, especially in allopolyploids, the hybridization of divergent genomes could contribute to various abnormalities, such as variability in chromosome number, structural rearrangements, and/or disorders in inheritance patterns. Here we studied these issues in allotetraploid Festuca pratensis × Lolium perenne hybrids.
Cytogenetic procedures, including fluorescent in situ hybridization, genomic in situ hybridization, and molecular markers - inter-simple sequence repeats (ISSR) were exploited. This cytogenetic approach indicated the dynamics in the number and distribution of ribosomal RNA genes and structural rearrangements for both parental genomes (Festuca and Lolium) in hybrid karyotypes. The separate analysis of F. pratensis and L. perenne chromosomes in hybrid plants (F-F generations of F. pratensis × L. perenne) revealed the asymmetrical level of rearrangements. Recognized structural changes were mainly located in the distal part of chromosome arms, and in chromosomes bearing ribosomal DNA, they were more frequently mapped in arms without this sequence. Based on the ISSR markers distribution, we found that the tetrasomic type of inheritance was characteristic for the majority of ISSR loci, but the disomic type was also observed. Nonetheless, no preference in the transmission of either Festuca or Lolium alleles to the following generations of allotetraploid F. pratensis × L. perenne hybrid was observed.
Our study reports cytogenetic and molecular genotyping of the F. pratensis × L. perenne hybrid and its following F-F progenies. The analysis of 137 allotetraploid F. pratensis × L. perenne hybrids revealed the higher level of recombination in chromosomes derived from F. pratensis genome. The results of ISSR markers indicated a mixed model of inheritance, which may be characteristic for these hybrids.
羊茅属和黑麦草属的物种以及属间羊茅属×黑麦草属（Festulolium）杂种是全球农业和美化用途有价值的饲料和草坪草。Festulolium 杂种可以在其基因组中融合具有重要农艺特性的基因。然而，在多倍体植物中，尤其是在异源多倍体中，不同基因组的杂交可能导致各种异常，如染色体数目变异、结构重排和/或遗传模式紊乱。在这里，我们研究了这些在异源四倍体羊茅×多年生黑麦草杂种中的问题。
我们利用细胞遗传学程序，包括荧光原位杂交、基因组原位杂交和分子标记——简单序列重复间（ISSR）进行了研究。这种细胞遗传学方法表明了核糖体 RNA 基因的数量和分布以及杂种核型中两个亲本基因组（羊茅和黑麦草）的结构重排的动态。在杂种植物（羊茅×黑麦草的 F-F 代）中分别分析羊茅和黑麦草的染色体表明，重排的不对称水平不同。已识别的结构变化主要位于染色体臂的远端，在携带核糖体 DNA 的染色体中，它们更频繁地位于没有该序列的臂上。基于 ISSR 标记的分布，我们发现大多数 ISSR 位点的遗传方式为四体遗传，但也观察到二体遗传。然而，在向异源四倍体羊茅×多年生黑麦草杂种的后代传递羊茅或黑麦草等位基因方面没有偏好。
我们的研究报告了羊茅×黑麦草杂种及其后续 F-F 后代的细胞遗传学和分子基因型分析。对 137 个异源四倍体羊茅×黑麦草杂种的分析表明，来自羊茅基因组的染色体具有更高的重组水平。ISSR 标记的结果表明，这可能是这些杂种的特征，存在一种混合遗传模式。
