Non-additive expression of awn development regulatory genes in the bread wheat lines with introgressions from Amblyopyrum muticum

Aim. Nonadditive expression of homeotic genes is considered to cause the development of nonparental phenotypes in the plants of hybrid origin. Previously, orthologs of rice and barley awn development regulators TaTOB1, TaDL, TaKNOX3, and TaETT2 were identified in the bread wheat genome sequence. Nonadditive expression of these regulators can be the reason for the emergence of non-parental terminally awned phenotypes among the bread wheat lines with introgressions from Amblyopyrum muticum Methods. Gene expression was identified with end-point detection RT-qPCR Results. Introgressive lines have expression of TaTOB1, TaKNOX3, and TaETT2 at the lower level compared to parents. As orthologs of TaTOB1 and TaKNOX3 are negative regulators of awn development in rice and barley, their reduced expression could have caused the appearance of terminally awned plants among introgressive lines. Neverthless, the reduced expression of the genes wasn’t specific to the lines with non-parental phenotype. Conclusions. Due to the lack of correlation between reduced expression of the genes studied and non-parental phenotype of the introgressive lines, the role of nonadditive expression of  TaTOB1, TaKNOX3, and TaETT2 in the development of this phenotype is not clear. Keywords: amphidiploids, non-additive expression, developmental genetics, awns.