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: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:YxaL is conserved within the Bacillus subtilis species complex associated with plants and soil. The mature YxaL protein contains a repeated beta-propeller domain, but the subcellular location and function of YxaL has not been determined. The gene encoding the mature YxaL protein was PCR amplified from genomic DNA of B. velezensis strain GH1-13 and used for recombinant protein production. A rabbit polyclonal antibody against the purified YxaL was generated and used for western blotting to determine the constitutive expression and secretion of YxaL. During normal culture growth of strain GH1-13, levels of the constitutively secreted YxaL were slowly rising to 100 μg L-1, and degraded with a half-life of 1.6 h in the culture medium. When the effects of YxaL on plant seed germination and seedling growth were examined, it was shown that seed treatment of Arabidopsis thaliana and rice (Oryza sativa L.) with purified YxaL at the optimal concentration of 1 mg L-1 was effective at improving the root growth of plants. Seedlings from the treated Arabidopsis seeds markedly increased transcription of a 1-aminocyclopropane-1-carboxylate synthetase marker gene (ACS11) but reduced expression of auxin- and abscisic acid-responsive marker genes (IAA1, GH3.3, and ABF4), especially when provided with exogenous auxin. Horticulture experiments showed that pepper (Capsicum annuum) seeds treated with 1 mg L-1 YxaL in a soaking solution increased shoot growth and improved tolerance to drought stress. We hypothesize that YxaL secreted from plant growth-promoting Bacillus cells has a significant impact on plant roots, with the potential to improve plant growth and stress tolerance.
Project description:Transcriptional profiling of C. perfringens 13 strain compared with strain 13∆cpe1786 erm after growth in minimal medium with 0.5 mM cystine.