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Centromeric DNA characterization in the model grass Brachypodium distachyon provides insights on the evolution of the genus
Author(s) -
Li Yinjia,
Zuo Sheng,
Zhang Zhiliang,
Li Zhanjie,
Han Jinlei,
Chu Zhaoqing,
Hasterok Robert,
Wang Kai
Publication year - 2018
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13832
Subject(s) - brachypodium distachyon , brachypodium , genus , biology , dna , characterization (materials science) , botany , genome , genetics , gene , nanotechnology , materials science
Summary Brachypodium distachyon is a well‐established model monocot plant, and its small and compact genome has been used as an accurate reference for the much larger and often polyploid genomes of cereals such as Avena sativa (oats), Hordeum vulgare (barley) and Triticum aestivum (wheat). Centromeres are indispensable functional units of chromosomes and they play a core role in genome polyploidization events during evolution. As the Brachypodium genus contains about 20 species that differ significantly in terms of their basic chromosome numbers, genome size, ploidy levels and life strategies, studying their centromeres may provide important insight into the structure and evolution of the genome in this interesting and important genus. In this study, we isolated the centromeric DNA of the B. distachyon reference line Bd21 and characterized its composition via the chromatin immunoprecipitation of the nucleosomes that contain the centromere‐specific histone CENH 3. We revealed that the centromeres of Bd21 have the features of typical multicellular eukaryotic centromeres. Strikingly, these centromeres contain relatively few centromeric satellite DNA s; in particular, the centromere of chromosome 5 (Bd5) consists of only ~40 kb. Moreover, the centromeric retrotransposons in B. distachyon ( CRB ds) are evolutionarily young. These transposable elements are located both within and adjacent to the CENH 3 binding domains, and have similar compositions. Moreover, based on the presence of CRB ds in the centromeres, the species in this study can be grouped into two distinct lineages. This may provide new evidence regarding the phylogenetic relationships within the Brachypodium genus.