Transcriptional analysis of wild-type and delta_dasR mutant of Streptomyces coelicolor grown in soil amended with chitin
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ABSTRACT: Genome-wide microarray analysis was performed using RNA extracted from soil cultures of Streptomyces coelicolor A3(2) in the presence or absence of chitin. The vast majority of genes in chitin and amino sugar metabolism, as well as many other genes for carbon and energy, nitrogen and sulfur metabolism, were differentially expressed in response to addition of chitin. Moreover, the gene expressions of eight gene clusters for secondary metabolites were also significantly up-regulated in the chitin amended soil. To reveal the role of a pleiotropic transcriptional regulator, DasR, which has been reported to be involved in regulation of chitin metabolism, antibiotic production and morphological differentiation, the gene expression patterns of wild type and dasR mutant in soil amended with chitin were compared by microarray analysis. The dasR mutation resulted in up-regulation of four antibiotic gene clusters and down-regulation of chitin metabolism.
Project description:Genome-wide microarray analysis was performed using RNA extracted from soil cultures of Streptomyces coelicolor A3(2) in the presence or absence of chitin. The vast majority of genes in chitin and amino sugar metabolism, as well as many other genes for carbon and energy, nitrogen and sulfur metabolism, were differentially expressed in response to addition of chitin. Moreover, the gene expressions of eight gene clusters for secondary metabolites were also significantly up-regulated in the chitin amended soil. To reveal the role of a pleiotropic transcriptional regulator, DasR, which has been reported to be involved in regulation of chitin metabolism, antibiotic production and morphological differentiation, the gene expression patterns of wild type and dasR mutant in soil amended with chitin were compared by microarray analysis. The dasR mutation resulted in up-regulation of four antibiotic gene clusters and down-regulation of chitin metabolism. A study using total RNA extracted from soil cultures of Streptomyces ceolicolor A3(2). A whole genome microarray of S. coelicolor (NimbleGen Custom Prokaryotic Gene Expression 72K 4-plex Arrays) was designed and manufactured by Roche (Roche NimbleGen, Madison, WI). Each array contained four sets of 8 sequence-specific 60-mer probes per gene corresponding to 7825 genes from the S. coelicolor A3(2) genome.
Project description:Soil microorganisms carry out decomposition of complex organic carbon molecules, such as chitin. High diversity of the soil microbiome and complexity of the soil habitat has posed a challenge to elucidate specific interactions between soil microorganisms. Here, we overcame this challenge by studying a model soil consortium (MSC-2) that is composed of 8 species. The MSC-2 isolates were originally obtained from the same soil that was enriched with chitin as a substrate. Our aim was to elucidate specific roles of the 8 member species during chitin metabolism in soil. The 8 species were added to sterile soil with chitin and incubated for 3 months. Multi-omics was used to understand how the community composition, transcript and protein expression and chitin-related metabolites shifted during the incubation period. The data clearly and consistently revealed a temporal shift during chitin decomposition and defined contributions by individual species. A Streptomyces species was a key player in early steps of chitin decomposition, followed by other members of MSC-2. These results illustrate how multi-omics applied to a defined consortium untangles complex interactions between soil microorganisms.
Project description:Analysis of 14-day-old Columbia-0 seedlings treated with chito-tetramer.Results provide insight into the signaling pathways involved in plant devlopment in response to the four-mer. Chitin is the second biopolymer most abundant at nature, after cellulose, forming part of insect exosqueletons, crustacean shells, krill and fungal spores where is present as a high molecular weight molecule. Previously we showed that Arabidopsis defense related clusters of genes were induced by high molecular weight chitin (CHH) or 8mer oligosaccharides similarly (Ramonell et al., 2005), some of those genes were essential for effective defense against phytopathogenic fungus (Berrocal-Lobo et al., 2010). At this work we show that differentially, a chitin oligosaccharide of lower molecular weight (4mer), induce genes in Arabidopsis related principally to vegetative growth, development and carbon and nitrogen metabolism.
Project description:Chitin soil amendment is known to improve soil quality, plant growth and plant stress resilience, but the underlying mechanisms are not well understood. In this study, we monitored chitin’s effect on lettuce physiology every two weeks through an eight-week growth period, analyzed the early transcriptional reprogramming and related metabolomic changes of lettuce, in response to crab chitin treatment in peat-based potting soil. In commercial growth conditions, chitin amendment still promoted lettuce growth, increased chlorophyll content, the number of leaves and crop head weight from week six. The flavonoid content in lettuce leaves was altered as well, showing an increase at week two but a decrease from week six. Transcriptomic analysis showed that over 300 genes in lettuce root were significant differentially expressed after chitin soil treatment. Gene Ontology-term (GO) enrichment analysis revealed statistical overrepresentation of GO terms linked to photosynthesis, pigment metabolic process and phenylpropanoid metabolic process. Further analysis of the differentially expressed genes (DEGs) showed that the flavonoid pathway is mostly upregulated whereas the bifurcation of upstream phenylpropanoid pathway towards lignin biosynthesis is mostly downregulated. Metabolomic analysis revealed the upregulation of salicylic acid, chlorogenic acid, ferulic acid, and p-coumaric acid in chitin treated lettuce seedlings. These phenolic compounds mainly influence the phenylpropanoid biosynthesis pathway and may play important roles in plant defense reactions. Our results suggest that chitin soil amendments might activate induced resistance by priming lettuce plants and promote lettuce growth via transcriptional changes.
Project description:C-di-AMP is primarily associated with the regulation of carbon utilization as well as other central traits, central metabolism, and bacterial stringent response to environmental changes. Elevated c-di-AMP levels result in aberrant physiology for most c-di-AMP synthesizing organisms, drawing particular attention to the importance of the c-di-AMP homeostasis and the molecular mechanisms pertaining to nucleotide metabolism and signal transduction. Here we show that c-di-AMP binds the GntR-family regulator DasR, uncovering a direct link between c-di-AMP and GlcNAc signaling. Further, we show c-di-AMP functions as an allosteric activator of DasR activity. GlcNAc is necessary for cell-surface structure from bacteria to humans, as well as a signal for bacterial development and antibiotic production. DasR is a global repressor that oversees GlcNAc metabolism and antibiotic production, which enables Actinobacteria to cope with stress and starvation. Our in vivo studies reveal the important biological role of allosteric regulation by c-di-AMP in metabolic imbalance and the transduction of a series of signals. Notably, DasR also controls intracellular c-di-AMP level through direct repression on disA. Overall, we identify a function of allosteric regulation between c-di-AMP and DasR in global signal integration and c-di-AMP homeostasis in bacteria, which is likely widespread in Actinobacteria.
Project description:The project is focused on the highly conserved sRNA scr5329 in Streptomyces coelicolor. A proteomics approach revealed that the sRNA regulates several metabolic enzymes, among them the Phosphoenolpyruvate-Carboxykinase (PEPCK), a key enzyme of the central carbon metabolism. The sRNA scr5239 promotes its degradation on the post-transcriptional level. The expression itself is dependent on the global transcriptional regulator DasR, which is N-acetylglucosamine-responsive thereby creating a feedback regulation. By post-transcriptional regulation of PEPCK and likely more targets, scr5239 adds an additional layer to the DasR regulatory network, providing a tool to control the metabolism in dependency to the carbon source.
Project description:Background: During the lifetime of a fermenter culture, the soil bacterium S. coelicolor undergoes a major metabolic switch from exponential growth to antibiotic production. We have studied gene expression patterns during this switch, using a specifically designed Affymetrix genechip and a high-resolution time-series of fermenter-grown samples. Results: Surprisingly, we find that the metabolic switch actually consists of multiple finely orchestrated switching events. Strongly coherent clusters of genes show drastic changes in gene expression already many hours before the classically defined transition phase where the switch from primary to secondary metabolism was expected. The main switch in gene expression takes only 2 hours, and changes in antibiotic biosynthesis genes are delayed relative to the metabolic rearrangements. Furthermore, global variation in morphogenesis genes indicates an involvement of cell differentiation pathways in the decision phase leading up to the commitment to antibiotic biosynthesis. Conclusions: Our study provides the first detailed insights into the complex sequence of early regulatory events during and preceding the major metabolic switch in S. coelicolor, which will form the starting point for future attempts at engineering antibiotic production in a biotechnological setting. Keywords: time course
Project description:Members of the Vibrionaceae family are often found associated with chitin-containing organisms and they are thought to play a major role in chitin degradation. The purpose of the present study was to determine how chitin affected the transcriptome and metabolome of two bioactive Vibrionaceae strains, Vibrio corallilyticus and Photobacterium galatheae. We focused on chitin degradation genes and secondary metabolites based on the assumption that these molecules in nature confer an advantage to the producer. Growth on chitin caused up-regulation of genes related to chitin metabolism and of genes potentially involved in host colonization and/or infection. The expression of genes involved in secondary metabolism was also significantly affected by growth on chitin, in one case being thirty-four folds upregulated. This was reflected in the metabolome, where the antibiotics andrimid and holomycin were produced in higher amounts on chitin. Interestingly, in cultures of P. galatheae grown on chitin we detected high amounts of the biogenic amine phenylethylamine. Overall, these results suggest that both V. coralliilyticus and P. galatheae have a specific lifestyle for growth on chitin, and that the secondary metabolites they produce are likely to play a crucial role during chitin colonization.
Project description:Members of the Vibrionaceae family are often found associated with chitin-containing organisms and they are thought to play a major role in chitin degradation. The purpose of the present study was to determine how chitin affected the transcriptome and metabolome of two bioactive Vibrionaceae strains, Vibrio corallilyticus and Photobacterium galatheae. We focused on chitin degradation genes and secondary metabolites based on the assumption that these molecules in nature confer an advantage to the producer. Growth on chitin caused up-regulation of genes related to chitin metabolism and of genes potentially involved in host colonization and/or infection. The expression of genes involved in secondary metabolism was also significantly affected by growth on chitin, in one case being thirty-four folds upregulated. This was reflected in the metabolome, where the antibiotics andrimid and holomycin were produced in higher amounts on chitin. Interestingly, in cultures of P. galatheae grown on chitin we detected high amounts of the biogenic amine phenylethylamine. Overall, these results suggest that both V. coralliilyticus and P. galatheae have a specific lifestyle for growth on chitin, and that the secondary metabolites they produce are likely to play a crucial role during chitin colonization.