title: Diploid/polyploid syntenic shuttle mapping and haplotype-specific chromosome walking toward a rust resistance gene (Bru1) in highly polyploid sugarcane (2n approximately 12x approximately 115).
abstract: The genome of modern sugarcane cultivars is highly polyploid (approximately 12x), aneuploid, of interspecific origin, and contains 10 Gb of DNA. Its size and complexity represent a major challenge for the isolation of agronomically important genes. Here we report on the first attempt to isolate a gene from sugarcane by map-based cloning, targeting a durable major rust resistance gene (Bru1). We describe the genomic strategies that we have developed to overcome constraints associated with high polyploidy in the successive steps of map-based cloning approaches, including diploid/polyploid syntenic shuttle mapping with two model diploid species (sorghum and rice) and haplotype-specific chromosome walking. Their applications allowed us (i) to develop a high-resolution map including markers at 0.28 and 0.14 cM on both sides and 13 markers cosegregating with Bru1 and (ii) to develop a physical map of the target haplotype that still includes two gaps at this stage due to the discovery of an insertion specific to this haplotype. These approaches will pave the way for the development of future map-based cloning approaches for sugarcane and other complex polyploid species.
authors.affiliation: CIRAD, UMR DAP, Montpellier, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Le Cunff
authors.forename: Olivier
authors.initials: O
authors.lastname: Garsmeur
authors.forename: Louis Marie
authors.initials: LM
authors.lastname: Raboin
authors.forename: Jérome
authors.initials: J
authors.lastname: Pauquet
authors.forename: Hugues
authors.initials: H
authors.lastname: Telismart
authors.forename: Athiappan
authors.initials: A
authors.lastname: Selvi
authors.forename: Laurent
authors.initials: L
authors.lastname: Grivet
authors.forename: Romain
authors.initials: R
authors.lastname: Philippe
authors.forename: Dilara
authors.initials: D
authors.lastname: Begum
authors.forename: Monique
authors.initials: M
authors.lastname: Deu
authors.forename: Laurent
authors.initials: L
authors.lastname: Costet
authors.forename: Rod
authors.initials: R
authors.lastname: Wing
authors.forename: Jean Christophe
authors.initials: JC
authors.lastname: Glaszmann
authors.forename: Angélique
authors.initials: A
authors.lastname: D'Hont