Volume 17 Part 1 Article 11: Molecular Characterisation of the Interaction between Agaricus bisporus and Its Mycopathogen Verticillium fungicola

Volume 17 Part 1 Article 11
Year 2008
Title: Molecular Characterisation of the Interaction between Agaricus bisporus and Its Mycopathogen Verticillium fungicola
Authors: J. Thomas, M. Sergeant, A. Costa, P. Collopy, A. Bailey, G. Foster, P. Mills and M. Challen


‘Dry bubble’ disease of the white button mushroom Agaricus bisporus results from infections with Verticillium fungicola. Only a single fungicide (prochloraz) is effective against the disease, and tolerance has been observed in UK isolates of the pathogen. Recent advances in Agaricus and Verticillium molecular genetic technologies provide opportunities to further dissect the infection processes and to gain an understanding of the genetic, biochemical and physiological processes that regulate the interaction between the fungal host and its mycopathogen. We have exploited a combination of approaches to characterise the fungal–fungal interaction. Suppressive subtractive hybridisation (SSH) and cDNA libraries of A. bisporus infected with V. fungicola were used to identify pools of host and pathogen response genes, either up- or down-regulated during development of disease lesions (cap spotting). Bioinformatic analysis revealed a range of response genes with various biological functions including: biotic and abiotic stress; signalling; protein synthesis; and cell wall structure and function.

Functional gene studies in homobasidiomycete mushrooms have been hampered by the lack of effective gene-silencing methods. The multinucleate nature of these fungi makes approaches used in other model organisms, like gene disruption, difficult to achieve. This has further constrained studies into the mechanisms underlying pathogenesis. To expedite functional analysis of disease response genes, we have developed RNAi hairpin-mediated gene suppression for A. bisporus. Specific mushroom genes identified from SSH-cDNA libraries and belonging to different functional groups have been down-regulated and are being functionally characterised through infection trials and quantitative polymerase chain reaction approaches. The approaches developed in this project should reveal mechanisms regulating the host–pathogen interaction between Agaricus and Verticillium and enable novel approaches for disease control.

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