title: Intergenomic rearrangements after polyploidization of Kengyilia thoroldiana (Poaceae: Triticeae) affected by environmental factors.
abstract: Polyploidization is a major evolutionary process. Approximately 70-75% species of Triticeae (Poaceae) are polyploids, involving 23 genomes. To investigate intergenomic rearrangements after polyploidization of Triticeae species and to determine the effects of environmental factors on them, nine populations of a typical polyploid Triticeae species, Kengyilia thoroldiana (Keng) J.L.Yang et al. (2n = 6x = 42, StStPPYY), collected from different environments, were studied using genome in situ hybridization (GISH). We found that intergenomic rearrangements occurred between the relatively large P genome and the small genomes, St (8.15%) and Y (22.22%), in polyploid species via various types of translocations compared to their diploid progenitors. However, no translocation was found between the relatively small St and Y chromosomes. Environmental factors may affect rearrangements among the three genomes. Chromosome translocations were significantly more frequent in populations from cold alpine and grassland environments than in populations from valley and lake-basin habitats (P<0.05). The relationship between types of chromosome translocations and altitude was significant (r = 0.809, P<0.01). Intergenomic rearrangements associated with environmental factors and genetic differentiation of a single basic genome should be considered as equally important genetic processes during species' ecotype evolution.
authors.affiliation: The National Key Facilities for Crop Gene Resources and Genetic Improvement (NFCRI), Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Qiuxia
authors.initials: Q
authors.lastname: Wang
authors.forename: Huitao
authors.initials: H
authors.lastname: Liu
authors.forename: Ainong
authors.initials: A
authors.lastname: Gao
authors.forename: Xinming
authors.initials: X
authors.lastname: Yang
authors.forename: Weihua
authors.initials: W
authors.lastname: Liu
authors.forename: Xiuquan
authors.initials: X
authors.lastname: Li
authors.forename: Lihui
authors.initials: L
authors.lastname: Li
mesh_terms: D000531:Altitude; D032461:Chromosomes, Plant / Q000235:genetics; D004777:Environment; D015321:Gene Rearrangement / Q000235:genetics*; D014644:Genetic Variation; D018745:Genome, Plant / Q000235:genetics*; D005838:Genotype; D006109:Poaceae / Q000235:genetics*; D011123:Polyploidy