Genome change in wheat observed through the structure and expression of α/β-gliadin genes

• Published in: Functional & integrative genomics Vol. 12; no. 2; pp. 341 - 355
• Main Authors: Kawaura, K, Wu, J, Matsumoto, T, Kanamori, H, Katagiri, S, Ogihara, Y
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-06-2012; Springer
• Subjects: Animal Genetics and Genomics; Bacterial artificial chromosomes; Biochemistry; Bioinformatics; Biological and medical sciences; Biomedical and Life Sciences; Cell Biology; Chromosome 1; chromosome translocation; Chromosome translocations; Chromosomes, Artificial, Bacterial - genetics; clones; Cloning, Molecular; Contig Mapping; Crossing-over; Differentiation; Diploids; DNA Transposable Elements; Evolution, Molecular; Fundamental and applied biological sciences. Psychology; Gene Duplication; Gene Expression; General aspects; Genetic Loci; Genome, Plant; gliadin; Gliadin - genetics; Gliadin - metabolism; Life Sciences; loci; Mathematics in biology. Statistical analysis. Models. Metrology. Data processing in biology (general aspects); Microbial Genetics and Genomics; Molecular Sequence Annotation; Molecular Sequence Data; Mutagenesis, Insertional; Original Paper; Phylogeny; Plant Genetics and Genomics; Promoters; Pseudogenes; Recombination; Replication; Retrotransposons; Sequence Analysis, DNA; Terminal Repeat Sequences - genetics; Transposons; Triticum - genetics; Triticum aestivum; wheat; BAC clone; Multigene; Genome sequence; Gene expression; Hexaploid wheat; α/β-gliadin; Monocotyledones; Nucleotide sequence; Artificial chromosome; Gene; Gramineae; Angiospermae; Gliadin; Cereal; Spermatophyta; Genome; Structure; Wheat; Triticum aestivum
• ISSN: 1438-793X; 1438-7948
• DOI: 10.1007/s10142-012-0269-0

To better understand genome structure and the expression of α/β-gliadin multigenes in hexaploid wheat, bacterial artificial chromosome (BAC) clones containing α/β-gliadin genes from the three loci, Gli-A2, Gli-B2, and Gli-D2, were screened. Based on their restriction fragment patterns, we selected five BAC clones, namely, two clones for Gli-A2, two clones for Gli-B2, and one clone for Gli-D2, to fully sequence. Approximately 200 kb was sequenced for each locus. In total, twelve α/β-gliadin intact genes and four pseudogenes were found, and retrotransposons or other transposons existed in each BAC clone. Dot-plot analysis revealed the pattern of genome segmental duplication within each BAC. We calculated time since duplication of each set of α/β-gliadin genes and insertion of retrotransposons. Duplication of all adjacent genes within the same BAC clone took place before or after allotetrapolyploidization, but duplication of certain genes occurred before diploid differentiation of wheat species. Retrotransposons were also inserted before and after the segmental duplication events. Furthermore, translocation of α/β-gliadin genes from chromosomes 1 to 6 apparently occurred before the diversification of various wheat genomes. Duplication of genome segments containing α/β-gliadin genes and retrotransposons were brought about through unequal crossing-over or saltatory replication and α/β-gliadin genes per se were duplicated without any recombination events. Out of twelve intact α/β-gliadin genes detected from their sequences, nine were expressed, although their patterns of expression were distinct. Since they have similar cis-elements and promoter structures, the mechanisms underlying their distinct gene expression and possible applications are discussed.