Survey of Arabidopsis- and Human-type Telomere Repeats in Plants Using Fluorescence in situ Hybridisation

Abstract

The nucleotide sequences of telomere repeats have been identified in many eukaryotes since Blackburn and Gall (1978), and these sequences are specific to the genus or higher taxonomic group. Wide vision telomere sequences are variable across eukaryotes. In plants, Arabidopsis-type telomere repeats (TTTAGGG)_n are dominant, although human-type telomere repeats (TTAGGG)_n have been reported in a few taxa. Recently, the evolution of these telomere repeats in plants has become the focus of many studies. In this report, the Arabidopsis-type telomere repeat and human-type telomere repeat were surveyed in 87 species of gymnosperms and angiosperms. In 1 gymnosperm species and 62 angiosperm species, fluorescence in situ hybridisation signals of both Arabidopsis-type and human-type telomere repeats were detected. Three gymnosperm species and 12 angiosperm species showed only signals of Arabidopsis-type telomere repeats. In 5 angiosperm species, only human-type telomere repeat signals were detected. The co-localisation of Arabidopsis- and human-type telomere repeats on chromosome ends in a wide range of plant species is a novel discovery that may elucidate the evolution of telomere repeats in plants.