title: Expression, mapping, and genetic variability of Brassica napus disease resistance gene analogues.
abstract: Numerous sequences analogous to resistance (R) genes exist in plant genomes and could be involved in resistance traits. The aim of this study was to identify a large number of Brassica napus sequences related to R genes and also to test the adequacy of specific PCR-based tools for studying them. Different consensus primers were compared for their efficiency in amplifying resistance-gene analogues (RGAs) related to the nucleotide-binding-site subgroup of R genes. Specific primers were subsequently designed to fine-study the different RGAs and we tested their efficiency in three species related to B. napus: Brassica oleracea, Brassica rapa, and Arabidopsis thaliana. Forty-four B. napus RGAs were identified. Among 29 examined, at least one-third were expressed. Eighteen RGAs were mapped on 10 of the 19 B. napus linkage groups. The high variability within these sequences permitted discrimination of each genotype within a B. napus collection. The RGA-specific primers amplified RGAs in the B. oleracea and B. rapa genomes, but the sequences appear to be poorly conserved in A. thaliana. Specific RGA primers are a precise tool for studying known-sequence RGAs. These sequences represent interesting markers that could be correlated with resistance traits in B. napus or related Brassica genomes.
authors.affiliation: Station de Génétique et Amelioration des Plantes, Institut National de la Recherche Agronomique, Versailles, France. fourmann@versailles.inra.fr
authors.forename: M
authors.initials: M
authors.lastname: Fourmann
authors.forename: F
authors.initials: F
authors.lastname: Chariot
authors.forename: N
authors.initials: N
authors.lastname: Froger
authors.forename: R
authors.initials: R
authors.lastname: Delourme
authors.forename: D
authors.initials: D
authors.lastname: Brunel
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D029688:Brassica napus / Q000235:genetics*; D002874:Chromosome Mapping; D017124:Conserved Sequence / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D018745:Genome, Plant; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000235:genetics*; D016415:Sequence Alignment