Characterization of genome repeat sequence composition and chromosomal distribution in Leymus secalinus

CHEN Jie; LI Yuan; YANG Ying; LIU Bo; DOU Quanwen

doi:10.7606/j.issn.1000-4025.20230751

Xibei zhiwu xuebao (Aug 2024)

Characterization of genome repeat sequence composition and chromosomal distribution in Leymus secalinus

CHEN Jie,
LI Yuan,
YANG Ying,
LIU Bo,
DOU Quanwen

Affiliations

CHEN Jie: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Crop Molecular Breeding of Qinghai Province, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
LI Yuan: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China; Key Laboratory of Crop Molecular Breeding of Qinghai Province, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
YANG Ying: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Crop Molecular Breeding of Qinghai Province, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
LIU Bo: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China; Key Laboratory of Crop Molecular Breeding of Qinghai Province, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
DOU Quanwen: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China; Key Laboratory of Crop Molecular Breeding of Qinghai Province, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China

DOI: https://doi.org/10.7606/j.issn.1000-4025.20230751
Journal volume & issue: Vol. 44, no. 8
pp. 1273 – 1282

Abstract

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Abstract [Objective] Leymus Hochst. stands as a crucial genetic resource for the genetic improvement and breeding of cereal crops. However, as allopolyploid plants, their genome origin remains unclear. This study aims to explore the genomic origin of the species in Leymus secalinus and the characteristics of interspecies genomic diversity by comparing the distribution of the repetitive sequences in the genomes of L. secalinus, L. racemosus, and Psathyrostachys juncea. [Methods] Genomic Cot-1DNA library of L. secalinus was constructed, and clones were sequenced and analyzed. The repetitive sequences were mapped to the chromosome of L. secalinus, L. racemosus, and P . juncea by fluorescence in situ hybridization (FISH). [Results] (1) The repetitive sequences of the Cot-1 DNA of L. secalinus were classified into 4 types based on their expected genomic distribution patterns: Tandem repeats, dispersed repeats, tandem mixed dispersed repeats, and uncharacterized repeats, representing 32.4%, 45.7%, 12.4%, and 9.5%, respectively. (2) The number of the hybridization sites of the tandem repeats TaiI-family, Lt1-6, pTa-535, and pSc250 were highly varied from 7-20, 1-14, 17-26, and 0-24, respectively, across different species and accessions. (3) Ten LTR repeats hybridized the tested species chromosomes mainly by 3 patterns. Hybridizations were distributed in centromere, pericentromere, and intercalary regions in all chromosomes. Hybridizations were distributed in all the chromosomes. Hybridizations were distributed the same as the pattern 1 except some chromosomes were carrying telomeric hybridizations. Two LTR/copia sequences were detected only in L. secalinus, while the others were detected in all species and accessions tested but with polymorphisms in hybridization intensities or hybridization patterns in partial chromosomes. [Conclusion] Some of the repetitive sequences in Leymus species may have the characteristics of rapid evolution, which supports the rapid homogenization spread of scattered repetitive sequences to the entire nuclear genome during the polyploidy of Leymus species.

Published in Xibei zhiwu xuebao

ISSN: 1000-4025 (Print)
Publisher: Science Press
Country of publisher: China
LCC subjects: Science: Biology (General); Science: Botany
Website: http://xbzwxb.alljournal.net/xbzwxben/home

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