title: Rapid evolutionary dynamics in a 2.8-Mb chromosomal region containing multiple prolamin and resistance gene families in Aegilops tauschii.
abstract: Prolamin and resistance gene families are important in wheat food use and in defense against pathogen attacks, respectively. To better understand the evolution of these multi-gene families, the DNA sequence of a 2.8-Mb genomic region, representing an 8.8 cM genetic interval and harboring multiple prolamin and resistance-like gene families, was analyzed in the diploid grass Aegilops tauschii, the D-genome donor of bread wheat. Comparison with orthologous regions from rice, Brachypodium, and sorghum showed that the Ae. tauschii region has undergone dramatic changes; it has acquired more than 80 non-syntenic genes and only 13 ancestral genes are shared among these grass species. These non-syntenic genes, including prolamin and resistance-like genes, originated from various genomic regions and likely moved to their present locations via sequence evolution processes involving gene duplication and translocation. Local duplication of non-syntenic genes contributed significantly to the expansion of gene families. Our analysis indicates that the insertion of prolamin-related genes occurred prior to the separation of the Brachypodieae and Triticeae lineages. Unlike in Brachypodium, inserted prolamin genes have rapidly evolved and expanded to encode different classes of major seed storage proteins in Triticeae species. Phylogenetic analyses also showed that the multiple insertions of resistance-like genes and subsequent differential expansion of each R gene family. The high frequency of non-syntenic genes and rapid local gene evolution correlate with the high recombination rate in the 2.8-Mb region with nine-fold higher than the genome-wide average. Our results demonstrate complex evolutionary dynamics in this agronomically important region of Triticeae species.
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Western Regional Research Center, Albany, CA, 94710, USA.|Department of Plant Sciences, University of California, Davis, CA, 95616, USA.|State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Lingli
authors.initials: L
authors.lastname: Dong
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Western Regional Research Center, Albany, CA, 94710, USA.|Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
authors.forename: Naxin
authors.initials: N
authors.lastname: Huo
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Western Regional Research Center, Albany, CA, 94710, USA.|Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
authors.forename: Karin
authors.initials: K
authors.lastname: Deal
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Daowen
authors.initials: D
authors.lastname: Wang
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Western Regional Research Center, Albany, CA, 94710, USA.
authors.forename: Tiezhu
authors.initials: T
authors.lastname: Hu
authors.affiliation: Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Dvorak
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Western Regional Research Center, Albany, CA, 94710, USA.
authors.forename: Olin D
authors.initials: OD
authors.lastname: Anderson
authors.affiliation: Department of Plant Sciences, University of California, Davis, CA, 95616, USA. mcluo@ucdavis.edu.
authors.forename: Ming-Cheng
authors.initials: MC
authors.lastname: Luo
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Western Regional Research Center, Albany, CA, 94710, USA. yong.gu@ars.usda.gov.
authors.forename: Yong Q
authors.initials: YQ
authors.lastname: Gu
mesh_terms: D032461:Chromosomes, Plant / Q000235:genetics*; D019143:Evolution, Molecular; D020440:Gene Duplication / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics; D010802:Phylogeny; D055315:Prolamins / Q000378:metabolism*; D014908:Triticum / Q000235:genetics*
chemical_list: D055315:Prolamins
keywords: Aegilops tauschii; Triticum aestivum; gene duplication; gene family; genome evolution; prolamin; recombination; resistance gene; synteny; wheat storage proteins