Cultivated grasses are an important source of food for domestic animals worldwide. Increased knowledge of their genomes can speed up the development of new cultivars with better quality and greater resistance to biotic and abiotic stresses. The most widely grown grasses are tetraploid ryegrass species (Lolium) and diploid and hexaploid fescue species (Festuca). In this work, we characterized repetitive DNA sequences and their contribution to genome size in five fescue and two ryegrass species as well as one fescue and two ryegrass cultivars. Partial genome sequences produced by Illumina sequencing technology were used for genome-wide comparative analyses with the RepeatExplorer pipeline. Retrotransposons were the most abundant repeat type in all seven grass species. The Athila element of the Ty3/gypsy family showed the most striking differences in copy number between fescues and ryegrasses. The sequence data enabled the assembly of the long terminal repeat (LTR) element Fesreba, which is highly enriched in centromeric and (peri)centromeric regions in all species. A combination of fluorescence in situ hybridization (FISH) with a probe specific to the Fesreba element and immunostaining with centromeric histone H3 (CENH3) antibody showed their co-localization and indicated a possible role of Fesreba in centromere function. Comparative repeatome analyses in a set of fescues and ryegrasses provided new insights into their genome organization and divergence, including the assembly of the LTR element Fesreba. A new LTR element Fesreba was identified and found in abundance in centromeric regions of the fescues and ryegrasses. It may play a role in the function of their centromeres.

中文翻译：

---

DNA重复序列的比较分析和在粪便和黑麦草中鉴定出一种新的费斯雷巴着丝粒元件。

耕种草是全世界家畜的重要食物来源。对它们的基因组的了解增加，可以加快新品种的开发，提高其质量，并更好地抵抗生物和非生物胁迫。生长最广泛的草是四倍体黑麦草种（黑麦草）以及二倍体和六倍体羊茅种（Festuca）。在这项工作中，我们表征了5个羊茅和2个黑麦草物种以及1个羊茅和2个黑麦草品种的重复DNA序列及其对基因组大小的贡献。由Illumina测序技术产生的部分基因组序列与RepeatExplorer管道一起用于全基因组比较分析。逆转座子是所有七个草种中最丰富的重复类型。Ty3 /吉普赛族的Athila元素在羊膜和黑麦草的复制数上表现出最明显的差异。序列数据使长末端重复（LTR）元件Fesreba的装配成为可能，该元件在所有物种的着丝粒和（周边）着丝粒区域中高度富集。荧光原位杂交（FISH）与对Fesreba元件具有特异性的探针结合并用着丝粒组蛋白H3（CENH3）抗体进行免疫染色的组合显示了它们的共定位作用，并表明了Fesreba在着丝粒功能中的可能作用。在一组粪便和黑麦草中进行的比较性重复组分析为他们的基因组组织和发散提供了新的见解，包括LTR元件Fesreba的组装。一个新的LTR元素Fesreba被发现并大量存在于羊茅和黑麦草的着丝粒区域。它可能在其着丝粒的功能中起作用。