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Viral Agents Causing Brown Cap Mushroom Disease of Agaricus Bisporus

Summary

This research investigated a viral disease that causes mushrooms to turn brown, making them unmarketable. The scientists discovered that a virus similar to those found in plants and fungi is responsible for the browning. They found that the virus can exist at two different levels in mushrooms – a low level that doesn’t cause visible symptoms and a high level that causes browning. The findings are important for the mushroom industry and our understanding of how viruses interact with fungi. Impacts on everyday life: – Helps mushroom farmers detect disease earlier before visible symptoms appear – Could lead to better disease control methods to maintain mushroom quality – Contributes to food security by protecting commercial mushroom crops – May reduce food waste by preventing crop losses – Provides insights that could help control other viral diseases in fungi

Background

Brown cap mushroom disease (BCMD) of cultivated Agaricus bisporus causes serious economic damage to the European mushroom industry. The disease is associated with double-stranded RNA molecules and exhibits symptoms including mushroom cap browning, primordial growth inhibition/delay, and cap malformations. The brown coloration symptom has particularly serious economic consequences due to market rejection.

Objective

To identify the causative agents of brown cap mushroom disease (BCMD) and understand how host responses lead to brown symptom development in Agaricus bisporus mushrooms.

Results

Ten RNA fragments were found to be upregulated over 1,000-fold between diseased and non-diseased tissue but were absent from the A. bisporus genome sequence. These fragments hybridized to double-stranded RNAs extracted from diseased tissue. The virus fragments were found at two distinct levels within infected mushrooms – at raised levels in infected, non-symptomatic white mushrooms and at much greater levels in infected brown mushrooms. Additionally, 9 upregulated and 32 downregulated host A. bisporus transcripts were identified. Chromametric analysis could distinguish color differences between non-infected white mushrooms and infected white mushrooms at early growth stages.

Conclusion

The researchers hypothesize that the identified transcript fragments represent components of a bipartite virus similar to the Partitiviridae family, which is the causative agent of BCMD. The virus exists at two distinct levels within infected mushrooms, suggesting a transition from persistent to acute viral infection determined during early mushroom development. The findings provide a basis for early disease detection and improve understanding of virus-fungus interactions in fruit body-forming fungi.
  • Published in:Applied and Environmental Microbiology,
  • Study Type:Laboratory Research,
  • Source: 10.1128/AEM.01093-15
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