Visualisation of MVX RNA in the mycelium of Agaricus bisporus by fluorescence in situ hybridisation

  • Oral Presentation
  • Plant Pathology
  • 12 Jun 2018 09:00
  • FS-G01, UCD Agriculture and food science Centre
  • View all IPSAM abstracts

Eoin O'Connor*
Maynooth University
Teagasc Food Research Centre

David Fitzpatrick
Maynooth University

Dan Eastwood
Swansea University

Helen Grogan
Teagasc Food Research Centre

*Presenting Author

Commercial mushroom crops (Agaricus bisporus) in Ireland and other parts of Europe are susceptible to a disease caused by a complex of 30 distinct RNA comprising 18 viruses known collectively as mushroom virus X (MVX). Symptoms of MVX include bare patches and mushroom cap discolouration (browning) in the fruiting bodies, associated with the multipartite viruses AbV6 and AbV16, respectively. Limited understanding exists of the localisation and mobilisation of these viruses within the mycelium of A. bisporus. To this end, a fluorescence in situ hybridisation (FISH) method was developed for in situ targeting of AbV6 RNA 2 and AbV16 RNA 1 in A. bisporus mycelium without use of destructive methods (e.g. fungal cell wall lysis for probe penetration) that results in delocalisation of the RNA targets. A. bisporus cultures associated with the bare patch disease phenotype showed predominantly high signal in the apices of hyphae when probed for AbV6 RNA 2, with a ‘halo-effect’ observed by high signal intensity around the vacuoles. A. bisporus cultures associated with the browning disease phenotype showed high signal intensities within reticulating networks of hyphae in a highly compartmentalised manor when probed for AbV16 RNA 1. These results show how the localisation of these two viruses in MVX infected cultures is dynamic, as both viruses are found in completely discrete areas of the mycelium in differential patterns. Moreover, findings of a ‘halo-effect’ around vacuoles and compartmentalisation of these viruses provide novel evidence that the viruses may mobilise via a vesicle-hijacking system. This study demonstrates that FISH is a powerful tool in the field of mycovirology.