The ends of linear chromosomes of most eukaryotes consist of protein-bound DNA arrays called telomeres, which play essential roles in protecting genome integrity. Despite general evolutionary conservation in function, telomeric DNA is known to drastically vary in length and sequence between different eukaryotic lineages. Bryophytes are a group of early diverging land plants that include mosses, liverworts, and hornworts. This group of ancient land plants recently emerged as a new model for important discoveries in genomics and evolutionary biology, as well as for understanding plant adaptations to a terrestrial lifestyle. We measured telomere length in different ecotypes of model Bryophyte species, including Physcomitrium patens, Marchantia polymorpha, Ceratodon purpureus, and in Sphagnum isolates. Our data indicate that all analyzed moss and liverwort genotypes have relatively short telomeres. Furthermore, all analyzed ecotypes and isolates of model mosses and liverworts display evidence of substantial natural variation in telomere length. Interestingly, telomere length also differs between male and female strains of the dioecious liverwort M. polymorpha and dioecious moss C. purpureus. Given that Bryophytes are extraordinarily well-adapted to different ecological niches from polar to tropical environments, our data will contribute to understanding the impact of natural telomere length variation on evolutionary adaptations in this ancient land plant lineage.

The ends of linear chromosomes of most eukaryotes consist of protein-bound DNA arrays called telomeres, which play essential roles in protecting genome integrity. Despite general evolutionary conservation in function, telomeric DNA is known to drastically vary in length and sequence between different eukaryotic lineages. Bryophytes are a group of early diverging land plants that include mosses, liverworts, and hornworts. This group of ancient land plants recently emerged as a new model for important discoveries in genomics and evolutionary biology, as well as for understanding plant adaptations to a terrestrial lifestyle. We measured telomere length in different ecotypes of model bryophyte species, including Physcomitrium patens, Marchantia polymorpha, Ceratodon purpureus, and in Sphagnum isolates. Our data indicate that all analyzed moss and liverwort genotypes have relatively short telomeres. Furthermore, all analyzed ecotypes and isolates of model mosses and liverworts display evidence of substantial natural variation in telomere length. Interestingly, telomere length also differs between male and female strains of the dioecious liverwort M. polymorpha and dioecious moss C. purpureus. Given that bryophytes are extraordinarily well adapted to different ecological niches from polar to tropical environments, our data will contribute to understanding the impact of natural telomere length variation on evolutionary adaptations in this ancient land plant lineage.

Telomeres are important specialized nucleoprotein structures at the ends of linear eukaryotic chromosomes involved in protecting DNA from damage. The functional characteristic of telomeres is the length. Changes in telomere structure is of enormous evolutionary importance as they can affect whole-genome stability. However, plants remain a poorly studied group in light of telomere biology. Bryophytes are a prospective plant group for understanding the protection and evolution mechanisms of plant telomeres. The aim of this work was to determine natural variability of telomere lengths in different bryophyte species and ecotypes. We used axenic cultures of moss Physcomitrium patens ecotypes (Gransden, Reute, Villersexel, Kaskaskia), moss Ceratodon purpureus (male R40 and female GG1), as well as natural isolates Sphagnum fallax MW, S. girgensohnii and Sphagnum sp. The analysis of the telomeres was carried out by the TRF method. It was found that different ecotypes of P. patens plants have different telomere lengths ranging from 1000 to 1500 bp. The mean telomere length in a female plant C. purpureus was 480–500 bp, and in a male plant 900–1000 bp. The telomere lengths of S. fallax MW and S. girgensohnii were mean ~2000 bp. However, telomeres were slightly shorter in isolates of Sphagnum sp., whose telomere length ranged from 1100 to 1500 bp. In addition, it was found that all studied bryophytes had differences in the location of specific telomeric sequences. Thus, we have shown that the telomere lengths of bryophytes can vary both between species and within one species. Furthermore, interstitial telomeric DNA is a distinguishing characteristic of bryophyte genomes.