title: Duplication and partitioning in evolution and function of homoeologous Q loci governing domestication characters in polyploid wheat.
abstract: The Q gene encodes an AP2-like transcription factor that played an important role in domestication of polyploid wheat. The chromosome 5A Q alleles (5AQ and 5Aq) have been well studied, but much less is known about the q alleles on wheat homoeologous chromosomes 5B (5Bq) and 5D (5Dq). We investigated the organization, evolution, and function of the Q/q homoeoalleles in hexaploid wheat (Triticum aestivum L.). Q/q gene sequences are highly conserved within and among the A, B, and D genomes of hexaploid wheat, the A and B genomes of tetraploid wheat, and the A, S, and D genomes of the diploid progenitors, but the intergenic regions of the Q/q locus are highly divergent among homoeologous genomes. Duplication of the q gene 5.8 Mya was likely followed by selective loss of one of the copies from the A genome progenitor and the other copy from the B, D, and S genomes. A recent V(329)-to-I mutation in the A lineage is correlated with the Q phenotype. The 5Bq homoeoalleles became a pseudogene after allotetraploidization. Expression analysis indicated that the homoeoalleles are coregulated in a complex manner. Combined phenotypic and expression analysis indicated that, whereas 5AQ plays a major role in conferring domestication-related traits, 5Dq contributes directly and 5Bq indirectly to suppression of the speltoid phenotype. The evolution of the Q/q loci in polyploid wheat resulted in the hyperfunctionalization of 5AQ, pseudogenization of 5Bq, and subfunctionalization of 5Dq, all contributing to the domestication traits.
authors: Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, USA.
authors: Zengcui
authors: Z
authors: Zhang
authors: Harry
authors: H
authors: Belcram
authors: Piotr
authors: P
authors: Gornicki
authors: Mathieu
authors: M
authors: Charles
authors: Jérémy
authors: J
authors: Just
authors: Cécile
authors: C
authors: Huneau
authors: Ghislaine
authors: G
authors: Magdelenat
authors: Arnaud
authors: A
authors: Couloux
authors: Sylvie
authors: S
authors: Samain
authors: Bikram S
authors: BS
authors: Gill
authors: Jack B
authors: JB
authors: Rasmussen
authors: Valérie
authors: V
authors: Barbe
authors: Justin D
authors: JD
authors: Faris
authors: Boulos
authors: B
authors: Chalhoub
mesh_terms: D020413:3' Untranslated Regions; D000483:Alleles; D002875:Chromosomes / Q000235:genetics*; D019143:Evolution, Molecular; D005091:Exons; D020440:Gene Duplication; D018745:Genome, Plant; D007438:Introns; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D011003:Ploidies; D011123:Polyploidy; D012333:RNA, Messenger / Q000378:metabolism; D014908:Triticum / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; D012333:RNA, Messenger