.Diversity of Gibberella zeae populations isolated from wheat in Argentina

CHULZE S.,; RAMIREZ, M.L; REYNOSO, M.M; FARNOCHI, M.C; TORRES, A.M; LESLIE, J,F

Monopoli, Italia

Conferencia; International Conference "Advances in genomics, biodiversity and rapid systems for detection of toxigenic fungi and mycotoxins".; 2006

European Commission-ISPA

Wheat (Triticum aestivum L.) is one of the main crops cultivated in the temperate central ?eastern area in Argentina. Its production reached approximately 16 million tons during the 2005 harvest season.. This cereal is an important component of the food chain and Argentina ranks as fourth in the world as wheat exporter. Gibberella zeae ( (Schwein.) Petch (anamoph Fusarium graminearum Schwabe) is the main pathogen associated with Fusarium Head Blight. In addition to yield losses, Fusarium contamination can results  in wheat grain contaminated with mycotoxins. To manage this pathogen it is important to know more about its population genetic structure. The objective of this study was - to evaluate the genetic diversity among populations of Gibberella zeae isolated from different regions in Argentina.  In order to evaluate the genetic variation in the maize pathogen Gibberella moniliformis (anamorph Fusarium verticillioides) we have studied 3 populations  zeaeisolated from the main wheat growing region in Argentina by molecular markers (AFLPs).The populations (133 isolates) were sampled during the 2002harvest season 1996/97 from commercial fieldsplanted with the same wheat hybrid.From  the 0three AAAT;CCCG and TG+TT216 92.6 . Average gof the 80.All these strains had AFLP profiles similar to those of standard isolates of G. zeae phylogenetic lineage 7. Among the members of G. moniliformis (133 isolates) a total of 182 AFLP loci were identified using two selective AFLP primer combinations. Of these 182 AFLP loci, 142 were polymorphic. The primer combination EcoRI+TT/MseI+CA produced 95 polymorphic of the 117 total bands (81%) y EcoRI+GG/MseI+CA produced 47 polymorphic of 65 total bands (72%). Genetic distance was calculated and isolates were all at most 84 % distant. Comparisons of AFLP allele frequencies among the three populations produce low GST values that indicate minimal geographic subdivision among the three subpopulations.