Origin and Fates of <i>TERT</i> Gene Copies in Polyploid Plants

• Main Authors: Petr Fajkus, Vratislav Peška, Jiří Fajkus, Eva Sýkorová
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: International Journal of Molecular Sciences
• Subjects: polyploidy; Nicotiana; telomerase; gene evolution; synteny
• Online Access: https://www.mdpi.com/1422-0067/22/4/1783
• ISSN: 1661-6596; 1422-0067

The gene coding for the telomerase reverse transcriptase (<i>TERT</i>) is essential for the maintenance of telomeres. Previously we described the presence of three <i>TERT</i> paralogs in the allotetraploid plant <i>Nicotiana tabacum,</i> while a single <i>TERT</i> copy was identified in the paleopolyploid model plant <i>Arabidopsis thaliana</i>. Here we examine the presence, origin and functional status of <i>TERT</i> variants in allotetraploid <i>Nicotiana</i> species of diverse evolutionary ages and their parental genome donors, as well as in other diploid and polyploid plant species. A combination of experimental and in silico bottom-up analyses of <i>TERT</i> gene copies in <i>Nicotiana</i> polyploids revealed various patterns of retention or loss of parental <i>TERT</i> variants and divergence in their functions. RT–qPCR results confirmed the expression of all the identified <i>TERT</i> variants. In representative plant and green algal genomes, our synteny analyses show that their <i>TERT</i> genes were located in a conserved locus that became advantageous after the divergence of eudicots, and the gene was later translocated in several plant groups. In various diploid and polyploid species, translocation of <i>TERT</i> became fixed in target loci that show ancient synapomorphy.