title: Molecular characterisation and polymorphism of MinLm1, a minisatellite from the phytopathogenic ascomycete Leptosphaeria maculans.
abstract: A sequence-characterised amplified region marker was identified in the phytopathogenic fungus Leptosphaeria maculans, which generated a single-banding pattern corresponding to six alleles showing size polymorphism between L. maculans field isolates. The size polymorphism was due to 2-7 tandem repeats of the 23-bp motif 5' TCTTACTTACATACACACCTCCC 3'. The repeated sequence, termed MinLm1, shares many features specific to minisatellites, e.g. a very strong G/C strand asymmetry, the presence of 6-bp direct repeats at both ends of the sequence and its occurrence in a region rich in microsatellites such as (CT)n, (ATG)n, (GTG)n and (CAT)n. MinLm1 shows a very high degree of conservation of the bases from one repeat to another and from one isolate to another (percent match range: 99.6-100%), whatever their geographical or temporal relatedness. MinLm1 is a single-locus minisatellite located on chromosomes sized 2.79 Mb and 2.48 Mb, of L. maculans isolates a.2 and H5, respectively. In agricultural populations of L. maculans, two alleles of MinLm1 were prevalent, corresponding to 2x and 5x repeats of the core motif. Differences in allele frequencies were observed in some cropping conditions, suggesting that MinLm1 is an informative marker for epidemiological studies of the pathogen.
authors.affiliation: Institut National de la Recherche Agronomique, Unité PMDV, Versailles, France.
authors.forename: A
authors.initials: A
authors.lastname: Attard
authors.forename: M
authors.initials: M
authors.lastname: Gourgues
authors.forename: L
authors.initials: L
authors.lastname: Gout
authors.forename: J
authors.initials: J
authors.lastname: Schmit
authors.forename: J
authors.initials: J
authors.lastname: Roux
authors.forename: J P
authors.initials: JP
authors.lastname: Narcy
authors.forename: M H
authors.initials: MH
authors.lastname: Balesdent
authors.forename: T
authors.initials: T
authors.lastname: Rouxel
mesh_terms: D000483:Alleles; D001203:Ascomycota / Q000235:genetics* / Q000472:pathogenicity; D001483:Base Sequence; D029688:Brassica napus / Q000382:microbiology; D004271:DNA, Fungal / Q000235:genetics; D019143:Evolution, Molecular; D005819:Genetic Markers; D005828:Genetics, Population; D016681:Genome, Fungal; D018598:Minisatellite Repeats; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012689:Sequence Homology, Nucleic Acid; D020080:Tandem Repeat Sequences
chemical_list: D004271:DNA, Fungal; D005819:Genetic Markers