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.
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: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:Little progress has been made in studying the toxicity of realistic 'non-pristine' forms of nanoparticles that presents in real soil environment. It is presently unkown whether the transformed nanoparticles in realistic environment exerts an adverse effect to rhizobium-legume symbiosis on molecular level. We used microarray to investigate the toxicogenomic responses of the model legume Medicago truncatula following 30 days exposure to three different types of biosolids (control biosolids (control BS), a mixture of Ag, ZnO and TiO2 manufactured nanomaterials added biosolids (Nano BS) and a corresponding bulk metals added biosolids (Bulk BS) ) amended soil that were aged for 6 months prior to exposure in pot experiment.