title: Cytological and molecular characterization of three gametoclones of Citrus clementina.
abstract: BACKGROUND
  Three gametoclonal plants of Citrus clementina Hort. ex Tan., cv. Nules, designated ESP, FRA, and ITA (derived from three labs in Spain, France, and Italy, respectively), were selected for cytological and molecular characterization in order to elucidate genomic rearrangements provoked by haploidization. The study included comparisons of their ploidy, homozygosity, genome integrity, and gene dosage, using chromosome counting, flow cytometry, SSR marker genotyping, and array-Comparative Genomic Hybridization (array-CGH).
  
  
  RESULTS
  Chromosome counting and flow cytometry revealed that ESP and FRA were haploid, but ITA was tri-haploid. Homozygous patterns, represented by a single peak (allele), were observed among the three plants at almost all SSR loci distributed across the entire diploid donor genome. Those few loci with extra peaks visualized as output from automated sequencing runs, generally low or ambiguous, might result from amplicons of paralogous members at the locus, non-specific sites, or unexpected recombinant alleles. No new alleles were found, suggesting the genomes remained stable and intact during gametogenesis and regeneration. The integrity of the haploid genome also was supported by array-CGH studies, in which genomic profiles were comparable to the diploid control.
  
  
  CONCLUSIONS
  The presence of few gene hybridization abnormalities, corroborated by gene dosage measurements, were hypothetically due to the segregation of hemizygous alleles and minor genomic rearrangements occurring during the haploidization procedure. In conclusion, these plants that are valuable genetic and breeding materials contain completely homozygous and essentially intact genomes.
authors.affiliation: University of Florida, Citrus Research and Education Center, Lake Alfred, FL, USA. fgmitter@ufl.edu.
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Germana
authors.forename: Pablo
authors.initials: P
authors.lastname: Aleza
authors.forename: Esther
authors.initials: E
authors.lastname: Carrera
authors.forename: Chunxian
authors.initials: C
authors.lastname: Chen
authors.forename: Benedetta
authors.initials: B
authors.lastname: Chiancone
authors.forename: Gilles
authors.initials: G
authors.lastname: Costantino
authors.forename: Dominique
authors.initials: D
authors.lastname: Dambier
authors.forename: Xiuxin
authors.initials: X
authors.lastname: Deng
authors.forename: Claire T
authors.initials: CT
authors.lastname: Federici
authors.forename: Yann
authors.initials: Y
authors.lastname: Froelicher
authors.forename: Wenwu
authors.initials: W
authors.lastname: Guo
authors.forename: Victoria
authors.initials: V
authors.lastname: Ibáñez
authors.forename: José
authors.initials: J
authors.lastname: Juárez
authors.forename: Kevin
authors.initials: K
authors.lastname: Kwok
authors.forename: François
authors.initials: F
authors.lastname: Luro
authors.forename: Marcos A
authors.initials: MA
authors.lastname: Machado
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Naranjo
authors.forename: Luis
authors.initials: L
authors.lastname: Navarro
authors.forename: Patrick
authors.initials: P
authors.lastname: Ollitrault
authors.forename: Gabino
authors.initials: G
authors.lastname: Ríos
authors.forename: Mikeal L
authors.initials: ML
authors.lastname: Roose
authors.forename: Manuel
authors.initials: M
authors.lastname: Talon
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xu
authors.forename: Fred G
authors.initials: FG
authors.lastname: Gmitter
mesh_terms: D000483:Alleles; D002957:Citrus / Q000235:genetics*; D018745:Genome, Plant / Q000235:genetics*; D006238:Haploidy; D006720:Homozygote
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