Project description:During the last decades, the use of plant growth promoting bacteria (PGPB) has been found to increase crop yield and quality and to confer abiotic and biotic stress tolerance. However, until now the PGPB mechanism to enhance plant performances is not clearly defined. Recently, our findings demonstrated that inoculations with both Kocuria rhizophila and Streptomyces violaceoruber, as well as their combination, determined an increase of tomato (Solanum lycopersicum) growth and development. In this study, through an advanced differential proteomic approach on tomato leaves, plant molecular mechanisms affected by both K. rhizophila and S. violaceoruber have been elucidated. To this aim, tomato plants were treated with K. rhizophila and/or Streptomyces violaceoruber cultures and grown on coconut fiber in greenhouse. In particular, PGPB treatments were conducted twice, on seed and after two weeks from the seedling by fertirrigation. Thus, the analyses have been performed at 14 days after sowing (DAS) (T1) and 42 DAS (T2). The results confirmed the growth stimulation ability of K. rhizophila/Streptomyces violaceoruber, showing shoot fresh and dry weight significantly improved at each time sampling. For the early phase (DAS-T1) comparative proteomics analysis of tomato plant leaves, 2 biological replicates were set up for the plants used as control (i.e. not subjected to treatment - samples I1 and I2-control I), 2 biological replicates for plants subjected to treatment with K. rhizophila (samples L1 and L2-treatment L), 2 biological replicates for plants subjected to treatment with S. violaceoruber (samples M1 and M2-treatment M), and 2 biological replicates for plants subjected to treatment with a mix of the two bacterial strains (samples N1 and N2-treatment N), for a total of 8 samples of leaf protein extracts. For the late phase (DAS-T2) comparative proteomics analysis of tomato plant leaves, 2 biological replicates were set up for the plants used as control (i.e. not treated - samples A1 and A2 - control A), 2 biological replicates for plants subjected to treatment with K. rhizophila (samples B1 and B2-treatment B), 2 biological replicates for plants subjected to treatment with S. violaceoruber (samples C1 and C2-treatment C), and 2 biological replicates for plants subjected to treatment with a mix of the two bacterial strains (samples D1 and D2-treatment D), for a total of 8 samples of leaf protein extracts. Proteomic analysis was able to identify 239 and 203 significantly differentially represented proteins (DRPs) at T1 and T2, respectively, comparing PGPB-treated vs. untreated control plants. KEGG Orthology (KO) identified DRP belonging to photosynthesis, biosynthesis of secondary metabolites, and carbon metabolism.
Project description:This study compared the genome of Streptomyces rimosus rimosus against that of Streptomyces coelicolor. It also compared 4 strains with changes in oxytetracycline production and derived from G7, the type strain, against G7. Keywords: Comparative genomic hybridization
Project description:When Streptomyces violaceoruber grows together with Streptomyces sp. MG7-G1, it reacts with strongly induced droplet production on its aerial mycelium. Initially the metabolite profile of droplets from S. violaceoruber in co-culture with Streptomyces sp. MG7-G1 was compared to samples from S. violaceoruber in single-culture by using high-performance liquid chromatography-mass spectrometry (HPLC-MS). Then, the exudate from agar plates of co-cultures and single cultures (after freezing and thawing) was also analysed. Several compounds were only observed when S. violaceoruber was grown in co-culture. Based on their high-resolution ESI mass spectra and their comparable retention times to the calcium-dependent antibiotics (CDAs) produced by S. violaceoruber, the new compounds were suspected to be deacylated calcium-dependent antibiotics (daCDAs), lacking the 2,3-epoxyhexanoyl residue of CDAs. This was verified by detailed analysis of the MS/MS spectra of the daCDAs in comparison to the CDAs. The major CDA compounds present in calcium ion-supplemented agar medium of co-cultures were daCDAs, thus suggesting that Streptomyces sp. MG7-G1 expresses a deacylase that degrades CDAs.
Project description:The food enzyme, a chitinase (EC 3.2.1.14), is produced with the genetically modified Streptomyces violaceoruber strain pChi by Nagase. No information was provided regarding the presence of antimicrobial resistance genes in the production strain, other than that used in the genetic modification. The chitinase is intended to be used in baking processes. Based on the maximum use levels recommended, dietary exposure to the food enzyme-total organic solids (TOS) was estimated on the basis of individual data from the EFSA Comprehensive European Food Consumption Database. The exposure estimate is up to 0.829 mg TOS/kg body weight per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-days oral toxicity study in rats. The Panel identified a no observed adverse effect level at the highest dose tested of 791 mg TOS/kg body weight, which, compared with the dietary exposure, results in margin of exposure of at least 1,171. Similarity of the amino acid sequence to those of known allergens was searched and no matches were found. The Panel considered that there are no indications for food allergic reactions to this chitinase. Based on the data provided and the derived margin of exposure, the Panel concluded that the food enzyme chitinase produced with the genetically modified S. violaceoruber strain pChi does not give rise to safety concerns arising from the toxicological studies and the production process under the intended conditions of use. The CEP Panel was unable to conclude on the absence of viable cells and DNA from the genetically modified production strain in the food enzyme, for which uncertainty remains on the possible presence of gene(s) conferring antimicrobial resistance.
Project description:We identified genome-wide binding regions of NdgR in Streptomyces coelicolor using chromatin immunoprecipitation sequencing (ChIP-seq). We constructed 6×myc-tagged NdgR strain using homologous recombination with myc-tagging vector. Analysis of the sequencing data aligned to Streptomyces coelicolor genome database (NC_003888).
Project description:We performed ribosome profiling which is the deep-sequencing of mRNA fragments protected by translating ribosome for two Streptomyces species through different growth phases to provide the translatome data