title: Genetic diversity of Mycosphaerella graminicola isolates from a single field.
abstract: Septoria tritici blotch caused by Mycosphaerella graminicola is currently one of the most economically damaging diseases on wheat crops worldwide. Two hundred and sixty single-conidial isolates of this fungus were sampled in April 2012 in the Nord-Pas de Calais region (France). They have all been collected from 13 distinct plots in a single field. The corresponding isolates were then fingerprinted using 8 microsatellite markers in order to assess the genetic diversity and population structure of M. graminicola at the single field scale. The results revealed a high genotypic diversity within the collected population, with the detection of 83% of unique haplotypes among the isolates tested (clonal fraction = 17%). A high genic diversity was also found as indicated by the Nei's index value (0.50) and strong allele diversity obtained (number of alleles per locus ranged from 7 to 17, with an average of 10 alleles per locus). Further analyses showed a low population differentiation (G(ST) = 0.08) and a high gene flow (Nm = 5.64) between the 13 sampled plots. Our study suggests that sexual reproduction, by its frequency, plays a major role in the genetic diversification of M. graminicola at the field level and in the distribution and homogenization of this diversity in the field via wind-born ascospores.
authors.forename: A
authors.initials: A
authors.lastname: Siah
authors.forename: Ph
authors.initials: P
authors.lastname: Reignault
authors.forename: P
authors.initials: P
authors.lastname: Halama
mesh_terms: D001203:Ascomycota / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D005602:France; D014644:Genetic Variation; D018895:Microsatellite Repeats; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D014908:Triticum / Q000382:microbiology*