Telomere sequence variability in genotypes from natural plant populations: unusual block-organized double-monomer terminal telomeric arrays.

0576215 - BÚ 2024 RIV GB eng J - Journal Article
Belyayev, Alexander - Kalendar, R. - Josefiová, Jiřina - Paštová, Ladislava - Habibi, Farzaneh - Mahelka, Václav - Mandák, Bohumil - Krak, Karol
Telomere sequence variability in genotypes from natural plant populations: unusual block-organized double-monomer terminal telomeric arrays.
BMC Genomics. Roč. 24, September (2023), č. článku 572. ISSN 1471-2164. E-ISSN 1471-2164
R&D Projects: GA ČR GA20-20286S
Institutional support: RVO:67985939
Keywords : evolution * Oxford nanopore sequencing * telomere
OECD category: Plant sciences, botany
Impact factor: 4.4, year: 2022
Method of publishing: Open access
https://doi.org/10.1186/s12864-023-09657-y

Telomeres are the nucleoprotein complexes that physically cap the ends of eukaryotic chromosomes. Most plants possess Arabidopsis-type telomere sequences (TSs). In addition to terminal TSs, more diverse interstitial TSs exists in plants. Although telomeres have been sufficiently studied, the actual diversity of TSs in land plants is underestimated.
We investigate genotypes from seven natural populations with contrasting environments of four Chenopodium species to reveal the variability in TSs by analyzing Oxford Nanopore reads. Fluorescent in situ hybridization was used to localize telomeric repeats on chromosomes. We identified a number of derivative monomers that arise in part of both terminal and interstitial telomeric arrays of a single genotype. The former presents a case of block-organized double-monomer telomers, where blocks of Arabidopsis-type TTTAGGG motifs were interspersed with blocks of derivative TTTAAAA motifs. The latter is an integral part of the satellitome with transformations specific to the inactive genome fraction.
We suggested two alternative models for the possible formation of derivative monomers from telomeric heptamer motifs of Arabidopsis-type. It was assumed that derivatization of TSs is a ubiquitous process in the plant genome but occurrence and frequencies of derivatives may be genotype-specific. We also propose that the formation of non-canonical arrays of TSs, especially at chromosomal termini, may be a source for genomic variability in nature.
Permanent Link: https://hdl.handle.net/11104/0348547