Formation of awns in wheat lines with introgressions from Aegilops spp. caused by novel regulatory genes

Abstract

Awns play a significant role in the plant physiology and are a well-known morphological marker in wheat. Awnedness in wheat is regulated by three inhibitors – Hd, B1, and B2, but awn promoters are still largely unknown. The present study is aimed at analysis of the expression level of awn development regulatory genes orthologs, TaDL, TaTOB1, TaETT2, and TaKNOX3, in Triticum aestivum, genome substitution amphidiploids AABBSshSsh and AABBUU, and derived lines with introgressions from Aegilops sharonensis and Ae. umbellulata.Expression of four mentioned genes was detected in the lemma of all strains studied, and the role of these genes in awn development was assumed. In awned introgression lines, expression of all studied genes differed from mid-parent value: it was present in parent genotypes and absent in derived lines. Non-additive expression of four studied genes in introgression lines is considered to be the possible reason that caused development of nonparental awned phenotype. The presence of two products resulting from TaTOB1 cDNA amplification, one of which contained fourth intron and another lacking it, is considered to be the result of two mRNA presence due to different TaTOB1 homoeoalleles expression.