Diversity of Gibberella zeae populations isolated from wheat in Argentina

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

Monopoli, Italia

Otro; Advances in genomics, biodiversity and Rapid systems for detection of toxigenic fungi and mycotoxins; 2006

Mycoglobe

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.  We studied three populations of G. zeae isolated from the main wheat growing region in Argentina by molecular markers (Amplified Fragment Length Polymorphisms – AFLPs). The populations were sampled during the 2002 harvest season from commercial fields planted with the same wheat hybrid. From  the AFLP analyses of 130 isolates with three primer pairs (EcoRI AA+/MseI+AT ;EcoRI+CC/MseI+CG and EcoRI+TG/MseI+TT) 216 bands were identified, of which 92.6 were polymorphic. Average genetic similarity of the isolates was 80%. All these strains had AFLP profiles similar to those of standard isolates of G. zeae phylogenetic lineage 7. Comparisons of the three populations resulted in low GST values which indicate minimal geographic subdivision among these three populations.