title: Evaluation of genetic variation among Brazilian soybean cultivars through genome resequencing.
abstract: BACKGROUND
  Soybean [Glycine max (L.) Merrill] is one of the most important legumes cultivated worldwide, and Brazil is one of the main producers of this crop. Since the sequencing of its reference genome, interest in structural and allelic variations of cultivated and wild soybean germplasm has grown. To investigate the genetics of the Brazilian soybean germplasm, we selected soybean cultivars based on the year of commercialization, geographical region and maturity group and resequenced their genomes.
  
  
  RESULTS
  We resequenced the genomes of 28 Brazilian soybean cultivars with an average genome coverage of 14.8X. A total of 5,835,185 single nucleotide polymorphisms (SNPs) and 1,329,844 InDels were identified across the 20 soybean chromosomes, with 541,762 SNPs, 98,922 InDels and 1,093 CNVs that were exclusive to the 28 Brazilian cultivars. In addition, 668 allelic variations of 327 genes were shared among all of the Brazilian cultivars, including genes related to DNA-dependent transcription-elongation, photosynthesis, ATP synthesis-coupled electron transport, cellular respiration, and precursors of metabolite generation and energy. A very homogeneous structure was also observed for the Brazilian soybean germplasm, and we observed 41 regions putatively influenced by positive selection. Finally, we detected 3,880 regions with copy-number variations (CNVs) that could help to explain the divergence among the accessions evaluated.
  
  
  CONCLUSIONS
  The large number of allelic and structural variations identified in this study can be used in marker-assisted selection programs to detect unique SNPs for cultivar fingerprinting. The results presented here suggest that despite the diversification of modern Brazilian cultivars, the soybean germplasm remains very narrow because of the large number of genome regions that exhibit low diversity. These results emphasize the need to introduce new alleles to increase the genetic diversity of the Brazilian germplasm.
authors.affiliation: Brazilian Corporation of Agricultural Research (Embrapa Soja), Carlos João Strass road, Warta County, PR, Brazil. jv_maldonado@hotmail.com.|Londrina State University (UEL), Celso Garcia Cid Road, km 380, Londrina, PR, Brazil. jv_maldonado@hotmail.com.
authors.forename: João Vitor
authors.initials: JV
authors.lastname: Maldonado dos Santos
authors.affiliation: National Center for Soybean Biotechnology and Division of Plant Sciences, University of Missouri, Columbia, MO, 65211, USA. valliyodanb@missouri.edu.
authors.forename: Babu
authors.initials: B
authors.lastname: Valliyodan
authors.affiliation: Informatics Institute and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA. joshitr@missouri.edu.|Department of Computer Science, University of Missouri, Columbia, MO, 65211, USA. joshitr@missouri.edu.
authors.forename: Trupti
authors.initials: T
authors.lastname: Joshi
authors.affiliation: Informatics Institute and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA. smk5g5@mail.missouri.edu.
authors.forename: Saad M
authors.initials: SM
authors.lastname: Khan
authors.affiliation: Informatics Institute and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA. ylmk2@mail.missouri.edu.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Informatics Institute and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA. wangjue@missouri.edu.
authors.forename: Juexin
authors.initials: J
authors.lastname: Wang
authors.affiliation: National Center for Soybean Biotechnology and Division of Plant Sciences, University of Missouri, Columbia, MO, 65211, USA. vuongt@missouri.edu.
authors.forename: Tri D
authors.initials: TD
authors.lastname: Vuong
authors.affiliation: Brazilian Corporation of Agricultural Research (Embrapa Soja), Carlos João Strass road, Warta County, PR, Brazil. marcelofernandes.oliveira@embrapa.br.
authors.forename: Marcelo Fernandes
authors.initials: MF
authors.lastname: de Oliveira
authors.affiliation: Brazilian Corporation of Agricultural Research (Embrapa Soja), Carlos João Strass road, Warta County, PR, Brazil. francismar.marcelino@embrapa.br.
authors.forename: Francismar Corrêa
authors.initials: FC
authors.lastname: Marcelino-Guimarães
authors.affiliation: Informatics Institute and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA. xudong@missouri.edu.|Department of Computer Science, University of Missouri, Columbia, MO, 65211, USA. xudong@missouri.edu.
authors.forename: Dong
authors.initials: D
authors.lastname: Xu
authors.affiliation: National Center for Soybean Biotechnology and Division of Plant Sciences, University of Missouri, Columbia, MO, 65211, USA. nguyenhenry@missouri.edu.|Informatics Institute and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA. nguyenhenry@missouri.edu.
authors.forename: Henry T
authors.initials: HT
authors.lastname: Nguyen
authors.affiliation: Brazilian Corporation of Agricultural Research (Embrapa Soja), Carlos João Strass road, Warta County, PR, Brazil. ricardo.abdelnoor@embrapa.br.|Londrina State University (UEL), Celso Garcia Cid Road, km 380, Londrina, PR, Brazil. ricardo.abdelnoor@embrapa.br.
authors.forename: Ricardo Vilela
authors.initials: RV
authors.lastname: Abdelnoor
mesh_terms: D000483:Alleles; D001938:Brazil; D016000:Cluster Analysis; D056915:DNA Copy Number Variations; D014644:Genetic Variation; D018745:Genome, Plant; D023281:Genomics / Q000379:methods; D059014:High-Throughput Nucleotide Sequencing; D054643:INDEL Mutation; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic; D013025:Glycine max / Q000145:classification / Q000235:genetics*