Polymorphism in the sequence of Glu1 gene in populations of Thinopyrum intermedium as a possible adaptive trait

Abstract

Aim. Compare structures of Glu genes, extracted from Th. intermedium plants grown in different microgeographic conditions. Methods. PCR with DNA samples of Th. intermedium and primers to Glu-1Dx and Glu-1Dy gene regions, sequencing and comparative analysis of polymorphic amplicons and sequences from databases. Results. Central fragments of Glu-1Dx and Glu-1Dy from plants grown in different microgeographic conditions had significant differences compared to corresponding sequences of Aegilops tauschii (Glu-1Dx), Thinopyrum intermedium (Glu-1St*2x), Triticum aestivum (Glu-1Dy) obtained from databases. Both genes had point mutations, deletions and insertions, which transformed glutamine coding triplets characteristic for storage proteins to stop-codons, also codons for cysteine, methionine and proline appeared. These aminoacids affect protein surface charge, hydrophilic/hydrophobic properties, conformation density, and structure stability. Conclusions. Changes in high molecular weight glutenin structure, which were caused by the observed mutations, could affect protease ability to effectively hydrolases them, which consequently could affect seed germination rate. Slow seed germination might be one of the mechanisms for survival of wild cereal species Thinopyrum intermedium under unfavorable environmental conditions.
Keywords: Thinopyrum intermedium, Glu-1Dх, Glu-1Dy, sequence, point mutations, stop codon.