Investigations into the fungal-fungal interaction between Verticillium fungicola and Agaricus bisporus

Abstract

Plant and animal pathogens section The cultivated button mushroom, Agaricus bisporus, is amenable to number of pathogenic threats including bacteria, viruses, mites, insects and fungi. Currently, the most significant threat to the commercial mushroom industry is the mycoparasite, Verticillium fungicola. Infection by V. fungicola can drastically reduce the yield and value of mushroom crops. The severity of this disease is dependent on the developmental stage of A. bisporus at the time of infection and is manifested in three types of symptoms: spotty cap, stipe blowout and dry bubble. An aim of our research has been to develop molecular tools for V. fungicola that will allow us to study the interaction between this pathogen and A. bisporus. These tools have included transformation methods, marker gene techniques as well as gene-knockout technologies. This has involved the use of Agrobacterium and T-DNA to introduce disruption constructs into V. fungicola as part of a molecular investigation into this fungal-fungal interaction. We have developed an efficient transformation system for V. fungicola that we have now adapted to give high levels of targeted mutagenesis. This technique has successfully generated targeted mutants of a β-1-6 glucanase homologue from Trichoderma harzianum and a Mitogen Activated Protein Kinase homologue (PMK1) from Magnaporthe grisea identified using degenerate PCR primers. We have also developed TDNA tagging technology in a mycology context for random mutagenesis in V. fungicola.