bacteriovorus HD100 attached to, invaded and killed P. tolaasii 2192T cells by forming bdelloplasts on the pileus surface, when added both before or after P. tolaasii 2192T inoculation (Figure 3d and e); thus, reduction in P. tolaasii 2192T numbers and disease symptoms was due to predatory activity by B. bacteriovorus HD100. As the consumer preference is for white, clean-looking mushrooms with minimal surface damage, the reduction in brown

blotch tissue LDN-193189 damage by B. bacteriovorus application could increase the yield and possibly the shelf life of high-quality, marketable mushrooms. This study investigated the survival of B. bacteriovorus HD100 and its predatory activity against P. tolaasii on the surface of post-harvest mushrooms up to 48 hours, sufficient time for brown blotch disease to develop on untreated mushrooms. Thus studies over longer time points, covering Torin 2 research buy time from transportation to the sell-by learn more date, would need to be investigated, in future work, if Bdellovibrio was to be applied as a treatment to extend shelf-life. In addition to reducing the population of P. tolaasii on the mushroom surface, Bdellovibrio are natural soil dwellers and so their application to casing soil could also prevent spread of brown blotch between mushrooms in the growth environment and between grow houses.

In this way, the fast swimming motility of Bdellovibrio [38] would allow efficient location of P. tolaasii prey, using chemotaxis, in the wet casing soil prior to mushroom growth initiation, and translocation by gliding along the mushroom pileus surface after mushroom fruiting bodies have formed, preventing P. tolaasii infection establishment at multiple stages of mushroom growth; previously, the possibility of infection throughout the mushroom growth period has been an obstacle in brown blotch disease

control. Further pre-harvest studies could investigate the longevity and protective effect of Bdellovibrio inoculated into the casing soil around mushroom mycelium, before Mannose-binding protein-associated serine protease and after fruiting body initiation, on growing A. bisporus. As Bdellovibrio preys efficiently upon some, but not all, species of Pseudomonas (unpublished observations), and some Pseudomonads in the casing soil such as P. putida are important in fruiting body initiation; further studies would additionally investigate the predatory activity of B. bacteriovorus HD100 against such commensal strains in vitro and in the casing soil to ensure that there are no effects that would have an adverse impact on mushroom fruiting body production. As host-dependent Bdellovibrio require prey cells to survive, the post-harvest treatment could also be self-limiting, as Bdellovibrio would die once P. tolaasii prey had been eradicated; further studies could quantify this. Furthermore, these in vitro and in vivo predation studies suggest that B. bacteriovorus may be able to survive the action of the toxins produced by P.