Project description:Bacillus velezensis strain GH1-13 isolated from a rice paddy soil in Korea has been reported to promote plant growth and inhibit some pathogens. It contains a plasmid pBV71, thought to be of benefit to the strain, but there is no information on its effect. In order to elicit the plasmid effect on gene expression, mRNA and protein levels were analyzed at various stages of bacterial growth. Comparative gene expression profiles between the plasmid-containing and plasmid-free cells revealed that strain GH1-13 activated a transient stress response in the exponential phase. It showed early activation of expression of sigma W operon, liaIHGFSR operon, and transcription regulators for transition state, associated with carbon catabolite repression and secondary metabolite biosynthesis of acetoin, bacillaene, and macrolactin.
Project description:Lecanicillium fungicola, the causative agent of dry bubble disease on Agaricus bisporus results in significant crop losses for mushroom growers worldwide. Dry bubble disease is treated through strict hygiene control methods and the application of chemical fungicides but an increase in fungicide resistant L. fungicola strains has resulted in a need to develop alternative biocontrol treatment methods. The aim of the work presented here was to evaluate the response of L. fungicola to a Bacillus velezensis isolate to assess its potential as a novel biocontrol agent. The bacterial species in Serenade, a commercially available biocontrol treatment was also included in this analysis. Exposure of 48 hr L. fungicola cultures to 25% v/v 96h B. velezensis culture filtrate resulted in a 45% reduction in biomass (P < 0.0002) and a disruption in hyphal structure and morphology. Characterisation of the proteomic response of L. fungicola following exposure to B. velezensis culture filtrate revealed an increase in the abundance of a variety of proteins associated with stress response (Norsolorinic acid reductase (+8 fold), isocitrate lyase (+7 fold) and MMS19 nucleotide excision repair protein (+4 fold). There was also a decrease in the abundance of proteins associated with transcription (40S ribosomal protein S30 (-33 fold), 60S ribosomal protein L5 (-45 foldThe results presented here indicate that B. velezensis culture filtrate is capable of inhibiting the growth of L. fungicola and inducing a stress response, thus indicating its potential to control this important pathogen of mushrooms.