Project description:Bacillus velezensis strain GH1-13 with a native conjugative plasmid (pBV71) is thought to be beneficial to the bacterium, although no information on its effects exists. Here we show that strain GH1-13 frequently lost the plasmid during normal growth conditions in a rich medium and changed the morphology and sensitivity to selenite and tellurite. Compared to the plasmid-cured cells, the wild-type and complemented cells exhibited multicellular behavior with the expression of conjugative type IV pili and regulatory Rap homologous genes that regulate the interconnection between conjugation and biofilm formation. Further omics-based analyses of morphogenesis, biofilm formation, and antibiotic synthesis suggest that the conjugative plasmid activates envelope stress responses in association with increased biosynthesis of extracellular polysaccharide and antibiotics for protective functions of the host during exponential phase.
Project description:The present study aims to evaluate the response of the three Mediterranean local grapevines ‘Garnacha Blanca’, ‘Garnacha Tinta’, and ‘Macabeo’ to treatments with biocontrol products (BPs), a botanical extract (Akivi, Dittrichia viscosa extract) and a beneficial microorganism (Bacillus UdG, Bacillus velezensis). A combination of transcriptomics and metabolomics approaches were chosen in order to study grapevine gene expression and to identify gene marker candidates, as well as, to determine grapevine metabolites differentially concentrated in response to BPs treatments. Grapevine plants were cultivated in greenhouse controlled conditions and submitted to the treatments, and thereafter, leaves were sampled 24h after treatment to conduct gene expression study by RNA-sequencing for ‘Garnacha Blanca’ leaves extract and by RT-qPCR for the three cultivars. Differentially expressed genes (DEGs) were investigated for both treatments and highly influenced DEGs were selected to be tested in the three cultivars as treatment gene markers. In addition, extraction of leaf components was performed to quantify metabolites such as phytohormones, organic acids, and phenols. Considering all the upregulated and downregulated genes and enhanced metabolites concentrations, the treatments had an effect on jasmonic acid, ethylene, and phenylpropanoids defense pathways. In addition, several DEG markers were identified presenting a stable overexpression after the treatments in the three grapevine cultivars. These gene markers could be used to monitor the activity of the products in field treatments in future research. Further research will be necessary to confirm these first results under field conditions.
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.