Analysis of the gliadin multigene loci in bread wheat using nullisomic-tetrasomic lines

Harberd, Nicholas P.; Bartels, Dorothea; Thompson, Richard

doi:10.1007/bf00383001

Cited by 95 publications

(45 citation statements)

References 26 publications

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“…Some other genomes, e.g., U and M from related species, also contain similar coding loci as shown in this work. The copy numbers of LMW-GS genes in common wheat were estimated to have 10-15 (Harberd et al 1985) or 35-40 (Sabelli and Shewry 1991;Cassidy et al 1998). Until now, the precise gene organizations at Glu-3 loci of different genomes are still not clear.…”

Section: Pcr Amplification and Cloning Of Lmw-gs Genesmentioning

confidence: 99%

A Novel Chimeric Low-Molecular-Weight Glutenin Subunit Gene From the Wild Relatives of Wheat Aegilops kotschyi and Ae. juvenalis: Evolution at the Glu-3 Loci

Gao

et al. 2008

Genetics

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Four LMW-m and one novel chimeric (between LMW-i and LMW-m types) low-molecular-weight glutenin subunit (LMW-GS) genes from Aegilops neglecta (UUMM), Ae. kotschyi (UUSS), and Ae. juvenalis (DDMMUU) were isolated and characterized. Sequence structures showed that the 4 LMW-m-type genes, assigned to the M genome of Ae. neglecta, displayed a high homology with those from hexaploid common wheat. The novel chimeric gene, designed as AjkLMW-i, was isolated from both Ae. kotschyi and Ae. juvenalis and shown to be located on the U genome. Phylogentic analysis demonstrated that it had higher identity to the LMW-m-type than the LMW-i-type genes. A total of 20 single nucleotide polymorphisms (SNPs) were detected among the 4 LMW-m genes, with 13 of these being nonsynonymous SNPs that resulted in amino acid substitutions in the deduced mature proteins. Phylogenetic analysis demonstrated that it had higher identity to the LMW-m-type than the LMW-i-type genes. The divergence time estimation showed that the M and D genomes were closely related and diverged at 5.42 million years ago (MYA) while the differentiation between the U and A genomes was 6.82 MYA. We propose that, in addition to homologous recombination, an illegitimate recombination event on the U genome may have occurred 6.38 MYA and resulted in the generation of the chimeric gene AjkLMW-i, which may be an important genetic mechanism for the origin and evolution of LMW-GS Glu-3 alleles as well as other prolamin genes.

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Section: Pcr Amplification and Cloning Of Lmw-gs Genesmentioning

confidence: 99%

A Novel Chimeric Low-Molecular-Weight Glutenin Subunit Gene From the Wild Relatives of Wheat Aegilops kotschyi and Ae. juvenalis: Evolution at the Glu-3 Loci

Gao

et al. 2008

Genetics

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“…The number of α-gliadin genes in different wheat cultivars and ancestral species varies significantly, ranging from 25 to 150 copies (Herberd et al 1985;Reeves and Okita 1987;). These differences are probably caused by duplication and deletion of chromosome segments, such as a wheat line lacking an entire cluster of the α-gliadin genes (D'Ovidio et al 1991).…”

Section: Introductionmentioning

confidence: 99%

Genomic organization of the complex α-gliadin gene loci in wheat

Crossman

Kong

et al. 2004

Theor Appl Genet

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To better understand the molecular evolution of the large alpha-gliadin gene family, a half-million bacterial artificial chromosome (BAC) library clones from tetraploid durum wheat, Triticum turgidum ssp. durum (2n = 4x = 28, genome AB), were screened for large genomic segments carrying the alpha-gliadin genes of the Gli-2 loci on the group 6 homoeologous chromosomes. The resulting 220 positive BAC clones--each containing between one and four copies of alpha-gliadin sequences--were fingerprinted for contig assembly to produce contiguous chromosomal regions covering the Gli-2 loci. While contigs consisting of as many as 21 BAC clones and containing up to 17 alpha-gliadin genes were formed, many BAC clones remained as singletons. The accuracy of the order of BAC clones in the contigs was verified by Southern hybridization analysis of the BAC fingerprints using an alpha-gliadin probe. These results indicate that alpha-gliadin genes are not evenly dispersed in the Gli-2 locus regions. Hybridization of these BACs with probes for long terminal repeat retrotransposons was used to determine the abundance and distribution of repetitive DNA in this region. Sequencing of BAC ends indicated that 70% of the sequences were significantly similar to different classes of retrotransposons, suggesting that these elements are abundant in this region. Several mechanisms underlying the dynamic evolution of the Gli-2 loci are discussed.

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“…Copy numbers are estimated based on Southern blot analyses, to vary from 10-15 (Harberd et al 1985) to 35-40 (Cassidy et al 1998;Sabelli and Shewry 1991) in hexaploid wheat. Analysis of coding sequences has shown that the LMW-GS polypeptides are composed of a signal peptide of 20 amino acids, a short N-terminal domain, a repetitive domain rich in glutamine residues, and a Cterminal domain (D'Ovidio and Masci 2004).…”

Section: Introductionmentioning

confidence: 99%

Novel LMW glutenin subunit genes from wild emmer wheat (Triticum turgidum ssp. dicoccoides) in relation to Glu-3 evolution

et al. 2014

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Four low-molecular-weight-isoleucine (LMW-i)-type and one novel chimeric (between LMW-i and LMW-methionine (m) types) low-molecular-weight glutenin subunit (LMW-GS) genes were characterized from wild emmer wheat (Triticum dicoccoides), designated as emmer-1 to emmer-5. All five LMW-GS genes possessed the same primary structure shared by other published LMW-GSs. The three genes emmer-1, emmer-3, and emmer-5 are similar, with the exception that emmer-3 and emmer-5 lost a few repeat motifs compared to emmer-1. Gene duplication and insertions/deletions of repeat motifs mediated through unequal crossing over may be responsible for the generation of these three Glu-3 alleles. Although the first residue of mature peptide of emmer-4 is isoleucine, it is not typical LMW-i-type LMW-GS. Phylogenetic analysis indicated that emmer-4 is located in the LMW-m subgroup, suggesting a closer relationship with LMW-m-type gene Y14104 of T. durum. Sequence alignment indicated that the emmer-4 is likely a chimeric gene generated by illegitimate recombination between LMW-i and LMW-m type. Unequal crossing over and illegitimate recombination are effective mechanisms for enriching both copy numbers and variations of LMW-GSs.

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Analysis of the gliadin multigene loci in bread wheat using nullisomic-tetrasomic lines

Cited by 95 publications

References 26 publications

A Novel Chimeric Low-Molecular-Weight Glutenin Subunit Gene From the Wild Relatives of Wheat Aegilops kotschyi and Ae. juvenalis: Evolution at the Glu-3 Loci

A Novel Chimeric Low-Molecular-Weight Glutenin Subunit Gene From the Wild Relatives of Wheat Aegilops kotschyi and Ae. juvenalis: Evolution at the Glu-3 Loci

Genomic organization of the complex α-gliadin gene loci in wheat

Novel LMW glutenin subunit genes from wild emmer wheat (Triticum turgidum ssp. dicoccoides) in relation to Glu-3 evolution

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