title: Molecular cytogenetics and DNA sequence analysis of an apomixis-linked BAC in Paspalum simplex reveal a non pericentromere location and partial microcolinearity with rice.
abstract: Apomixis in plants is a form of clonal reproduction through seeds. A BAC clone linked to apomictic reproduction in Paspalum simplex was used to locate the apomixis locus on meiotic chromosome preparations. Fluorescent in situ hybridisation revealed the existence of a single locus embedded in a heterochromatin-poor region not adjacent to the centromere. We report here for the first time information regarding the sequencing of a large DNA clone from the apomixis locus. The presence of two genes whose rice homologs were mapped on the telomeric part of the long arm of rice chromosome 12 confirmed the strong synteny between the apomixis locus of P. simplex with the related area of the rice genome at the map level. Comparative analysis of this region with rice as representative of a sexual species revealed large-scale rearrangements due to transposable elements and small-scale rearrangements due to deletions and single point mutations. Both types of rearrangements induced the loss of coding capacity of large portions of the "apomictic" genes compared to their rice homologs. Our results are discussed in relation to the use of rice genome data for positional cloning of apomixis genes and to the possible role of rearranged supernumerary genes in the apomictic process of P. simplex.
authors.affiliation: Institute of Plant Genetics CNR, Perugia via della madonna alta 130, 06128 Perugia, Italy.
authors.forename: Ornella
authors.initials: O
authors.lastname: Calderini
authors.forename: Song B
authors.initials: SB
authors.lastname: Chang
authors.forename: Hans
authors.initials: H
authors.lastname: de Jong
authors.forename: Alessandra
authors.initials: A
authors.lastname: Busti
authors.forename: Francesco
authors.initials: F
authors.lastname: Paolocci
authors.forename: Sergio
authors.initials: S
authors.lastname: Arcioni
authors.forename: Sacco C
authors.initials: SC
authors.lastname: de Vries
authors.forename: Marleen H C
authors.initials: MH
authors.lastname: Abma-Henkens
authors.forename: Renè M Klein
authors.initials: RM
authors.lastname: Lankhorst
authors.forename: Iain S
authors.initials: IS
authors.lastname: Donnison
authors.forename: Fulvio
authors.initials: F
authors.lastname: Pupilli
mesh_terms: D022202:Chromosomes, Artificial, Bacterial; D032461:Chromosomes, Plant; D020451:Contig Mapping; D004251:DNA Transposable Elements; D018744:DNA, Plant / Q000235:genetics*; D017353:Gene Deletion; D015321:Gene Rearrangement; D017343:Genes, Plant; D008040:Genetic Linkage; D005819:Genetic Markers; D018745:Genome, Plant; D006570:Heterochromatin / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D012275:Oryza / Q000235:genetics; D031781:Paspalum / Q000235:genetics*; D017354:Point Mutation; D012639:Seeds / Q000235:genetics; D013045:Species Specificity
chemical_list: D004251:DNA Transposable Elements; D018744:DNA, Plant; D005819:Genetic Markers; D006570:Heterochromatin