Volume 19 Part 1 Article 98
Title: Bioprotection of the cultivated mushroom Agaricus bisporus by Bacillus subtilis biofilms
Author: C. Pandin, R. Védie, T. Rousseau, A. Canette1, J. Deschamps, S. Aymerich, D. Le Coq, R. Briandet
Worldwide, food losses amount to about one third of food for human consumption, equivalent to about 1.3 billion tonnes per year (FAOSTAT). A large fraction of these losses is due to microbiological deterioration. Until recently, chemical pesticides were the most commonly used solution in agriculture because of their radical effectiveness. In France, since 2008, the government aims by 2018 to reduce by 50% the use of such pesticides through for sustainable agriculture (French plan EcoPhyto 2018), which led to the intensification of biological control in agriculture. The different modes of action of microbial biocontrol known to date are the stimulation of the host natural defences, toxin or antimicrobial substances production and nutrient competition, but the concept of biofilm which could involve other mechanisms of bioprotection is rarely mentioned. Biocontrol represents at the present time, 5% of the plant protection sector. In the sector of button mushrooms (Agaricus bisporus) in France, the biocontrol agent used since 2008 by more than 80% of the sector and compatible with organic agriculture is Bacillus subtilis QST713. It shows a clear biofungicidal effect against Trichoderma aggressivum (compost flooding) during cultivation of A. bisporus. However, the mechanisms involved in the bio-protection phenomenon are poorly documented to date. The study of Bacillus subtilis QST713 biofilm formation at different stages of A. bisporus cultivation will allow a better understanding of the mechanisms involved as spatial and nutritional competition towards competitors such as T. aggressivum or Pseudomonas tolaasii.