Oral Presentation Science Protecting Plant Health 2017

The banana wilt fungus Fusarium oxysporum f .sp. cubense is even more diverse than previously anticipated (4340)

Diane Mostert 1 , Wayne O'Neill 2 , Suzy Perry 2 , Lizel Mostert 1 , Altus Viljoen 1
  1. Plant Pathology, Stellenbosch University, Stellenbosch, Western Cape, South Africa
  2. Biosecurity Queensland, Department of Agriculture and Fisheries , Brisbane, Queensland, Australia

Fusarium oxysporum f. sp. cubense (Foc) is a soil-borne fungus that causes Fusarium wilt of banana, a lethal disease that can result in devastating economic losses to banana production worldwide. The fungus, which originated in Asia, has a complex evolutionary history and taxonomic composition. It consists of three races, which are inadequately defined, and at least 24 vegetative compatibility groups (VCGs) that are separated by single to multiple sequence differences in the loci governing vegetative compatibility. VCG complexes are regularly formed between closely related groups. Extensive surveys of diseased banana plants in Asia resulted in the collection of pathogenic isolates of F. oxysporum that did not fit into any of the known Foc VCGs. These isolates were, therefore, properly characterized and assigned to new Foc VCGs. In the process, five multiple-member and eight single-member VCGs were assigned. Isolates previously assigned as new genotypes of Foc paired with the known VCGs 01221, 01222 and the VCG complex 0128/01220. Phylogenetic analyses indicated that the new Foc VCGs were closely related. The results obtained in this study suggest that more VCGs exist than originally anticipated, but that Foc is probably phylogenetically less diverse than reflected by the number of VCGs.