Diversity and evolution of four dispersed repetitive DNA sequences in the genus Secale

Abstract

We present the first characterization of 360 sequences in six species of the genus Secale of both cultivated and wild accessions. These include four distinct kinds of dispersed repetitive DNA sequences named pSc20H, pSc119.1, pSaO5(411), and pSaD15(940) belonging to the Revolver family. During the evolution of the genus Secale from wild to cultivated accessions, the pSaO5(411)-like sequences became shorter mainly because of the deletion of a trinucleotide tandem repeating unit, the pSc20H-like sequences displayed apparent homogenization in cultivated rye, and the second intron of Revolver became longer. In addition, the pSc20H-, pSc119.1-, and pSaO5(411)-like sequences cloned from wild rye and cultivated rye could be divided into two large clades. No single case of the four kinds of repetitive elements has been inherited by each Secale accession from a lone ancestor. It is reasonable to consider the vertical transmission of the four repetitive elements during the evolution of the genus Secale. The pSc20H- and pSaO5(411)-like sequences showed evolutionary elimination at specific chromosomal locations from wild species to cultivated species. These cases imply that different repetitive DNA sequences have played different roles in the chromosome development and genomic evolution of rye. The present study adds important information to the investigations dealing with characterization of dispersed repetitive elements in wild and cultivated rye.

Involvement of Disperse Repetitive Sequences in Wheat/Rye Genome Adjustment

“…Moreover, a pSc20H sequence (accession number AF305943) BLAST revealed a sequence similarity between 83% and 97% with several retrotransposon gypsy -like partial sequences isolated from distinct Secale species ( S. cereale , S. vavilovii , S. strictum , S. sylvestre ) recently published [17]. Rye origin 1494 bp sequence also revealed between 81% and 79% sequence similarity with several Triticum sp.…”

“…pSc20H is a 1494 bp sequence related to retrotransposons of several plant species like sorghum, rice, pineapple, and Arabidopsis, dispersed throughout rye chromosomes, except at telomeric and nucleolar organizing regions [6,16]. Several rye-specific repetitive sequences, including pSc20H, have recently been pointed out as excellent tools to assess evolutive patterns of rye species [17]. We have previously disclosed the strong involvement of retrotransposon and microsatellite flanking sequences mainly clustered in sub-telomeric domains in genome restructuring in the wheat-rye system.…”

Introgression of chromosome segments from multiple alien species in wheat breeding lines with wheat streak mosaic virus resistance

“…Sec-1 and NOR position are based on Lei et al (2012). Asterisks (*) represent repetitive DNA markers (Tang et al, 2011) for which chromosomal positions are proposed here; UL-Thin5 is a new marker. Line N02Y5018, N02Y5019 and N02Y2016 has the translocation BP between Xgwm0911 and Xbarc194.…”

Production and cytomolecular identification of new wheat-perennial rye (Secale cereanum) disomic addition lines with yellow rust resistance (6R) and increased arabinoxylan and protein content (1R, 4R, 6R)

“…Recent characterization of 360 repetitive elements in six species of the genus Secale implies that repetitive DNA sequences have played important roles in the course of chromosome evolution of rye (Tang et al 2011b). …”