Phylogenetic relationship of a new class of LMW-GS genes in the M genome of Aegilops comosa

• Published in: Theoretical and applied genetics Vol. 122; no. 7; pp. 1411 - 1425
• Main Authors: Wang, Ke, Gao, Liyan, Wang, Shunli, Zhang, Yanzhen, Li, Xiaohui, Zhang, Miaoyi, Xie, Zhenze, Yan, Yueming, Belgard, Matthew, Ma, Wujun
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.05.2011; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Aegilops; Aegilops comosa; Agriculture; Amino Acid Sequence; Amino acids; Angiosperms; Base Sequence; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Classical genetics, quantitative genetics, hybrids; Cloning, Molecular; cysteine; DNA; DNA, Plant - genetics; dough; Escherichia coli - metabolism; Evolution, Molecular; Fundamental and applied biological sciences. Psychology; Gene Expression; Genes; Genes, Plant; Genetic aspects; Genetics of eukaryotes. Biological and molecular evolution; Genome, Plant; Genomes; Genomics; glutenins; Glutens - chemistry; Goat grass; homologous recombination; INDEL Mutation; Life Sciences; Molecular Sequence Data; Molecular Weight; Original Paper; Phylogenetics; Phylogeny; Physiological aspects; Plant Biochemistry; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant proteins; Polymerase Chain Reaction; Polymorphism, Single Nucleotide; prediction; Protein Subunits - chemistry; Protein Subunits - genetics; Proteins; Pteridophyta, spermatophyta; Sequence Analysis, DNA; Sequence Homology, Amino Acid; signal peptide; single nucleotide polymorphism; Triticum - genetics; Triticum - metabolism; Vegetals; Australia; China; Beijing China; Repetitive Domain; Common Wheat; Illegitimate Recombination; Aegilops Species; High Molecular Weight Glutenin Subunit; Monocotyledones; Aegilops; Gene; Gramineae; Angiospermae; Genetics; Spermatophyta; Agriculture; Phylogeny; Genome
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-011-1541-8

A new class of low molecular weight glutenin subunit (LMW-GS) genes was isolated and characterized from Aegilops comosa (2n = 2x = 14, MM). Although their DNA structure displayed high similarity to LMW-i type genes, there are some key differences. The deduced amino acid sequences of their mature proteins showed that the first amino acid residue of each gene was leucine and therefore they were designated as LMW-l type subunits. An extra cysteine residue was present in the signal peptide and the first cysteine residue of mature proteins located at the end of repetitive domain. Additionally, a long insertion of 10-22 residues (LGQQPQ₅₋₁₇) occurred in the end of the C-terminal II. Comparative analysis demonstrated that LMW-l type glutenin genes possessed a great number of single-nucleotide polymorphisms and insertions/deletions. A new classification system was proposed according to the gene structure and phylogenetic analysis. In this new system, LMW-GS is classified into two major classes, LMW-M and LMW-I, with each including two subclasses. The former included LMW-m and LMW-s types while the latter contained LMW-l and LMW-i types. Analysis of their evolutionary origin showed that the LMW-l genes diverged from the group 2 of LMW-m type genes at about 12-14 million years ago (MYA) while LMW-i type evolved from LMW-l type at approximately 8-12 MYA. The LMW-s type was a variant form of group 1 of LMW-m type and their divergence occurred about 4-6 MYA. In addition to homologous recombination, non-homologous illegitimate recombination could be an important molecular mechanism for the origin and evolution of LMW-GS gene family. The secondary structure prediction suggested that the novel LMW-l type subunits, such as AcLMW-L1 and AcLMW-L2, may have positive effects on dough properties.