ARS | Publication request: THE NEPAL GIBBERELLA ZEAE PROJECT

Submitted to: National Fusarium Head Blight Forum Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 11, 2001
Publication Date: N/A

Technical Abstract: Sampling of a small area in the Nepal Himalaya has identified Gibberella zeae populations with an unusually high level of biodiversity. From farms in this area, we collected G. zeae strains from five kinds of samples: seed samples of wheat, rice, and maize, and samples of soil debris and weeds. We classified genetic diversity of 575 strains using a species-specific, polymorphic SCAR marker, that placed all the strains into one of five SCAR types. To investigate associations between genotype, virulence, and toxin production, we characterized 250 strains for virulence on wheat heads and for production of the trichothecenes nivalenol (NIV) and deoxynivalenol (DON). One-third of the strains tested produced only DON and two-thirds produced NIV. In SCAR types 1, 2, and 5, >95% of the strains in each type produced the same toxin, either DON or NIV, but in type 3 equal numbers of DON-producers and NIV-producers were present. Virulence on wheat was influenced significantly both by SCAR type and toxin type, with higher virulence on wheat associated with DON production. Because the SCAR analysis measures genetic variability at only one locus, additional studies are in progress using amplified fragment-length polymorphisms to obtain information on fine genetic structure of the population of G. zeae from Nepal. This work should allow us to determine whether Nepal is a center of diversity for G. zeae, and to evaluate the potential of the Nepal G. zeae population for generation of novel genotypes of potential concern for wheat head blight management worldwide.