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Clonal populations of Leptosphaeria maculans contaminating cabbage in Mexico
Author(s) -
Dilmaghani A.,
Gout L.,
MorenoRico O.,
Dias J. S.,
Coudard L.,
CastilloTorres N.,
Balesdent M.H.,
Rouxel T.
Publication year - 2013
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/j.1365-3059.2012.02668.x
Subject(s) - biology , leptosphaeria maculans , brassica oleracea , genetic diversity , botany , mating type , population , linkage disequilibrium , brassica , genotype , genetics , haplotype , demography , sociology , gene
The race structure and genotypic diversity of four Leptosphaeria maculans populations isolated from Brassica oleracea (broccoli, cauliflower, cabbage, etc.) in central Mexico (Aguascalientes, Guanajuato and Zacatecas states) were analysed. Race structure was characterized by an unusually low diversity at three locations out of four. Fourteen minisatellite markers revealed a high proportion of repeated multilocus genotypes in these populations, combined with a significant linkage disequilibrium and strong clonal fraction (65–87%). The occurrence of the mating‐type idiomorphs always significantly departed from the 1:1 proportion expected in the case of random mating. Each population thus consists of a few (four to nine) multilocus genotypes which are specific to each location. These data strongly support the hypothesis of exclusive, or a high rate of, clonal multiplication. Comparison of cropping practices between B. oleracea and B. napus indicate that the shift in reproductive behaviour of the fungus is chiefly man‐mediated.