Implications of an inverted duplication in the wheat <i>KN1</i>-type homeobox gene <i>Wknox1</i> for theorigin of Persian wheat

Abstract

Introgression between related species with different ploidy levels has played important roles in wheat subspecies differentiation. Persian wheat, a cultivated tetraploid wheat subspecies (Triticum turgidum subsp. carthlicum), is postulated to have evolved through interploidy hybridization between tetraploid and hexaploid wheats. Here, we report evidence for the origin of subsp. carthlicum based on the discovery of a new allele for the 5th-to-6th exon region of the Wknox1bKNOTTED1-type homeobox gene in a common wheat subspecies (T. aestivum subsp. carthlicoides). In this Wknox1b region, subsp. carthlicoides contains an inverted duplication mutation in the 3' flanking region of a 157-bp MITE insertion site. This structural mutation resulted in the suppression of Wknox1b expression in subsp. carthlicoides, but no structural mutation was observed in the same region of subsp. carthlicum. In addition, the carthlicum allele for the Wknox1b 5th-to-6th exon region exhibited the same sequence as that in the wild emmer wheat subsp. dicoccoides. These observations support an alternative hypothesis that subsp. carthlicum evolved by interploidy hybridization between subsp. carthlicoides and tetraploid wheat.

Genetic Analysis of Hexaploid Wheat (Triticum aestivum L.) Using the Complete Sequencing of Chloroplast DNA and Haplotype Analysis of the Wknox1 Gene

“…In the present investigation, the genomic sequences of the Wknox1d fourth intron regions were amplified by PCR using the primer pair of Takumi a. Morimoto [ 18 ] ( Table 7 ). A common wheat, T. aestivum subsp.…”

“…Subsp. carthlicoides should be considered as the original and elder genotype from which genes for this particular morphology of the ear were transferred together with the Q-factor to T. carthlicum [ 3 , 18 ]. According to Kuckuck, this region was distinguished by a tremendous genetic variation in wheat including T. dicoccum, T. carthlicum and T. aestivum subsp.…”

“…The genomic sequences of the Wknox1d 4th intron regions were amplified by PCR using the primer pair of Takumi a. Morimoto [ 18 ]: 5′-AAAAAAAAGGTTAAATGGAC-3′ and 5′-ACCTTATACATGATTGGGAA-3′. The Wknox1b 5th-to-6th exon region was amplified by PCR using the primer pair 5′-GCTGAAGCACCATCTCCTGA-3′ and 5′-CATGTAGAAGGCGGCGTTAG-3′.…”

“…It should provide a concise and precise description of the experimental results, their interpretation, as well as the experimental conclusions that can be drawn. In the present investigation, the genomic sequences of the Wknox1d fourth intron regions were amplified by PCR using the primer pair of Takumi a. Morimoto [18] (Table 7). A common wheat, T. aestivum subsp.…”

“…A comparative study of the three Wknox1 genomic sequences revealed accumulation of numerous mutations, particularly in the fourth intron and the 5′-upstream region. Later, Takumi a. Morimoto [ 18 ] reported the discovery of a new allele for the fifth-to-sixth exon region of the Wknox1b KNOTTED1 -type homeobox gene in a common wheat subspecies ( T. aestivum subsp. carthlicoides ).…”