Genetic Variation Of LMW-GS Genes From Aegilops Sharonensis, Triticum Dicoccum And Their Hybrid Amphiploid

Aiming at revealing genetic variation of genes encoding LMW-GS of Ae. sharonensis, T. dicoccum and their hybrid amphiploid, we conducted isolating and multiple alignment of these genes. These results will be informative for quality improvement at breeding project of bread wheat. The results are as follows:1. Totally,64 gene sequences encoding LMW-GS were identified in this study. Of them,34 belong to type of LMW-m and the other 31 LMW-s. Among the 34 sequences (LMW-m type),9 genes and 1 pseudogene were identified from Ae. sharonensis with similarity ranging from 68.20% to 99.70%; 6 genes and 6 pseudogenes from T. dicoccum with similarity ranging from 53.11% to 99.89%; 5 genes and 6 pseudogenes from hybrid amphiploid with similarity ranging from 90.25% to 99.89%. While among the 31 sequences (LMW-s type),10 genes and 1 pseudogene were identified from Ae. sharonensis with similarity ranging from 86.24% to 99.79%; 9 genes and 1 pseudogenes from T. dicoccum with similarity ranging from 49.12% to 98.56%; 10 genes from hybrid amphiploid with similarity ranging from 62.95% to 99.81%.2. All of the eleven gene sequences encoding LMW-m isolated from hybrid amphiploid have higher similarity with those from the parent of T. dicoccum than those from Ae. sharonensis; while, all the 10 LMW-s genes from hybrid amphiploid have higher similarity with those from the parent of Ae. sharonensis than those from T. dicoccum.3. In the materials with types of LMW-m and LMW-s, the value of Ks/Ka was higher, showing that the synonymous substitutions per site for pairwise comparisons from LMW-m and LMW-s were more than non-synonymous substitutions. On the contrary, the value of Ks/Ka for pseudogenes was lower, showing that non-synonymous substitutions per site for pairwise comparisons from LMW-m and LMW-s were more than synonymous substitutions.4. The structures of amino acid for LMW-m and LMW-s were composed of signal peptide, N terminal, repeats area and C terminal. The domains of signal peptide and N terminal were conserved compared with repeats area and C terminal. The causes contributed to the differences among various genes were insertion, deletion and substitution of a given nucleotide acid.5. Phylogenetic analysis of genes encoding LMW-m and LMW-s showed that genes encoding LMW-m could be divided into 4 groups. The majority of genes from the hybrid amphiploid were classified into the same clade as those from T. dicoccum, showing that they were mainly derived from the parent of T. dicoccum. However, LMW-s genes were mainly divided into 2 groups. Most of the genes from the hybrid amphiploid were classified into the same clade as those from Ae. sharonensis, showing that they were mainly derived from the parent of Ae. sharonensis.