title: Homoeologous recombination in the presence of Ph1 gene in wheat.
abstract: A crossover (CO) and its cytological signature, the chiasma, are major features of eukaryotic meiosis. The formation of at least one CO/chiasma between homologous chromosome pairs is essential for accurate chromosome segregation at the first meiotic division and genetic recombination. Polyploid organisms with multiple sets of homoeologous chromosomes have evolved additional mechanisms for the regulation of CO/chiasma. In hexaploid wheat (2n = 6× = 42), this is accomplished by pairing homoeologous (Ph) genes, with Ph1 having the strongest effect on suppressing homoeologous recombination and homoeologous COs. In this study, we observed homoeologous COs between chromosome 5Mgof Aegilops geniculata and 5D of wheat in plants where Ph1 was fully active, indicating that chromosome 5Mgharbors a homoeologous recombination promoter factor(s). Further cytogenetic analysis, with different 5Mg/5D recombinants, showed that the homoeologous recombination promoting factor(s) may be located in proximal regions of 5Mg. In addition, we observed a higher frequency of homoeologous COs in the pericentromeric region between chromosome combination of rec5Mg#2S·5Mg#2L and 5D compared to 5Mg#1/5D, which may be caused by a small terminal region of 5DL homology present in chromosome rec5Mg#2. The genetic stocks reported here will be useful for analyzing the mechanism of Ph1 action and the nature of homoeologous COs.
authors.affiliation: Wheat Genetics Resource Center, Department of Plant Pathology, Throckmorton Plant Sciences Center, Kansas State University, Manhattan, KS, 66506-5502, USA.
authors.forename: Dal-Hoe
authors.initials: DH
authors.lastname: Koo
authors.affiliation: Wheat Genetics Resource Center, Department of Plant Pathology, Throckmorton Plant Sciences Center, Kansas State University, Manhattan, KS, 66506-5502, USA.|Laboratory of Cell and Chromosome Engineering, College of Life Sciences, Henan Agricultural University, Zhengzhou, 450002, China.
authors.forename: Wenxuan
authors.initials: W
authors.lastname: Liu
authors.affiliation: Wheat Genetics Resource Center, Department of Plant Pathology, Throckmorton Plant Sciences Center, Kansas State University, Manhattan, KS, 66506-5502, USA. friebe@ksu.edu.
authors.forename: Bernd
authors.identifier: 0000-0002-5419-1565
authors.initials: B
authors.lastname: Friebe
authors.affiliation: Wheat Genetics Resource Center, Department of Plant Pathology, Throckmorton Plant Sciences Center, Kansas State University, Manhattan, KS, 66506-5502, USA.
authors.forename: Bikram S
authors.initials: BS
authors.lastname: Gill
mesh_terms: D020223:Chromosome Painting; D023902:Chromosome Pairing; D032461:Chromosomes, Plant / Q000235:genetics*; D003434:Crossing Over, Genetic; D017343:Genes, Plant; D008540:Meiosis / Q000235:genetics; D011123:Polyploidy; D014908:Triticum / Q000235:genetics*
keywords: Aegilops geniculata; Homoeologous recombination; Meiotic synapsis; Triticum aestivum; Wheat