title: Genetic and epigenetic modifications to the BBAA component of common wheat during its evolutionary history at the hexaploid level.
abstract: The formation and evolution of common wheat (Triticum aestivum L., genome BBAADD) involves allopolyploidization events at two ploidy levels. Whether the two ploidy levels (tetraploidy and hexaploidy) have impacted the BBAA subgenomes differentially remains largely unknown. We have reported recently that extensive and distinct modifications of transcriptome expression occurred to the BBAA component of common wheat relative to the evolution of gene expression at the tetraploid level in Triticum turgidum. As a step further, here we analyzed the genetic and cytosine DNA methylation differences between an extracted tetraploid wheat (ETW) harboring genome BBAA that is highly similar to the BBAA subgenomes of common wheat, and a set of diverse T. turgidum collections, including both wild and cultivated genotypes. We found that while ETW had no significantly altered karyotype from T. turgidum, it diverged substantially from the later at both the nucleotide sequence level and in DNA methylation based on molecular marker assay of randomly sampled loci across the genome. In particular, ETW is globally less cytosine-methylated than T. turgidum, consistent with earlier observations of a generally higher transcriptome expression level in ETW than in T. turgidum. Together, our results suggest that genome evolution at the allohexaploid level has caused extensive genetic and DNA methylation modifications to the BBAA subgenomes of common wheat, which are distinctive from those accumulated at the tetraploid level in both wild and cultivated T. turgidum genotypes.
authors: Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China.
authors: Chang
authors: C
authors: Liu
authors: Xuejiao
authors: X
authors: Yang
authors: Huakun
authors: H
authors: Zhang
authors: Xutong
authors: X
authors: Wang
authors: Zhibin
authors: Z
authors: Zhang
authors: Yao
authors: Y
authors: Bian
authors: Bo
authors: B
authors: Zhu
authors: Yuzhu
authors: Y
authors: Dong
authors: Bao
authors: B
authors: Liu
mesh_terms: D044503:5-Methylcytosine / Q000378:metabolism; D005075:Biological Evolution; D019175:DNA Methylation / Q000235:genetics; D044127:Epigenesis, Genetic; D005455:Fluorescent Antibody Technique; D018745:Genome, Plant; D007399:Interphase; D007621:Karyotyping; D008677:Metaphase; D010641:Phenotype; D011110:Polymorphism, Genetic; D015203:Reproducibility of Results; D017422:Sequence Analysis, DNA; D013447:Sulfites; D057891:Tetraploidy; D014908:Triticum / Q000166:cytology / Q000235:genetics*
chemical_list: D013447:Sulfites; D044503:5-Methylcytosine; C042345:hydrogen sulfite