Project description:Purpose: Deconstructing the soil microbiome into reduced-complexity functional modules represents a novel method of microbiome analysis. The goals of this study are to confirm differences in transcriptomic patterns among five functional module consortia. Methods: mRNA profiles of 3 replicates each of functional module enrichments of soil inoculum in M9 media with either 1) xylose, 2) n-acetylglucosamine, 3) glucose and gentamycin, 4) xylan, or 5) pectin were generated by sequencing using an Illumina platform (GENEWIZ performed sequencing). Sequence reads that passed quality filters were aligned to a soil metagenome using Burrows Wheeler Aligner. Resulting SAM files were converted to raw reads using HTSeq, and annotated using Uniref90 or EGGNOG databases. Results: To reduce the size of the RNA-Seq counts table and increase its computational tractability, transcripts containing a minimum of 75 total counts, but no more than 3 zero counts, across the 15 samples were removed. The subsequent dataset was normalized using DESeq2, resulting in a dataset consisting of 6947 unique transcripts across the 15 samples, and 185,920,068 reads. We identified gene categories that were enriched in a sample type relative to the overall dataset using Fisher’s exact test. Conclusions: our dataset confirms that the functional module consortia generated from targeted enrichments of a starting soil inoculum had distinct functional trends by enrichment type.
Project description:The survival, pollutant degradation activity and transcriptome response was monitored in Sphingomonas sp. LH128 inoculated into soil. Cultivable cell numbers were determined by plating, while phenanthrene degradation was monitored by HPLC. The genetic base for the adaptive strategy of LH128 in soil was investigated by using microarray consisting 7,200 gene-coding ORFs. During 4 hours of incubation, 510 genes were differentially expressed (317 increased and 193 reduced expression) while 610 genes were differentially expressed (318 increased and 292 reduced) after 10 days of incubation. Genes with increased expression comprised of gene encoding PAH catabolic enzymes, stress resistance, oxidative stress tolerance, outer membrane proteins/porins and efflux pump proteins while the downregulated genes comprised of genes encoding flagellar biosynthesis, ribosomal proteins and ATPase. Transcriptomic response of phenanthrene degrading Sphingomonas sp. LH128 inoculated into phenanthrene contaminated soil after 4h and after 10 days of incubation was studied using genome-wide gene expression analysis. For this purpose, the strain was pregrown in minimal medium and inoculated at appropriated celld densitites. RNA was extracted both from soil and and from initial inoculum and cDNA was synthesized and labeled with Cy3. Transcriptomic response in soil of three replicates per conditions after both incubation duration were analyzed and compared with the initial inoculum
Project description:The experiment at three long-term agricultural experimental stations (namely the N, M and S sites) across northeast to southeast China was setup and operated by the Institute of Soil Science, Chinese Academy of Sciences. This experiment belongs to an integrated project (The Soil Reciprocal Transplant Experiment, SRTE) which serves as a platform for a number of studies evaluating climate and cropping effects on soil microbial diversity and its agro-ecosystem functioning. Soil transplant serves as a proxy to simulate climate change in realistic climate regimes. Here, we assessed the effects of soil type, soil transplant and landuse changes on soil microbial communities, which are key drivers in Earth’s biogeochemical cycles.
Project description:To study the soil mcirobial functional communities and the nutrient cycles couplings changes after exposure to different contaminant
Project description:The present invention relates to methods for determining soil quality, and especially soil pollution, using the invertebrate soil organism Folsomia candida also designated as springtail. Specifically, the present invention relates to a method for determining soil quality comprising: contacting Folsomia Candida with a soil sample to be analysed during a time period of 1 to 5 days; isolating said soil contacted Folsomia Candida; extracting RNA from said isolated soil contacted Folsomia Candida; determing a gene expression profile based on said extracted RNA using microarray technology; comparing said gene expression profile with a reference gene expression profile; and determing soil quality based expression level differences between said gene expression profile and said control expression profile.
Project description:Soil transplant serves as a proxy to simulate climate change in realistic climate regimes. Here, we assessed the effects of climate warming and cooling on soil microbial communities, which are key drivers in Earth’s biogeochemical cycles, four years after soil transplant over large transects from northern (N site) to central (NC site) and southern China (NS site) and vice versa. Four years after soil transplant, soil nitrogen components, microbial biomass, community phylogenetic and functional structures were altered. Microbial functional diversity, measured by a metagenomic tool named GeoChip, and phylogenetic diversity are increased with temperature, while microbial biomass were similar or decreased. Nevertheless, the effects of climate change was overridden by maize cropping, underscoring the need to disentangle them in research. Mantel tests and canonical correspondence analysis (CCA) demonstrated that vegetation, climatic factors (e.g., temperature and precipitation), soil nitrogen components and CO2 efflux were significantly correlated to the microbial community composition. Further investigation unveiled strong correlations between carbon cycling genes and CO2 efflux in bare soil but not cropped soil, and between nitrogen cycling genes and nitrification, which provides mechanistic understanding of these microbe-mediated processes and empowers an interesting possibility of incorporating bacterial gene abundance in greenhouse gas emission modeling.
Project description:Sorghum bicolor is one of the most important cereal crops in the world, predominantly grown in sub‑Saharan Africa by smallholder farmers. Despite its outstanding resilience to abiotic stresses, approximately 20% of sorghum yield is annually lost on the African continent due to infestation with the parasitic weed Striga hermonthica. Existing Striga management strategies to decrease Striga infestation often show low efficiency and are not easily integrated into current agricultural practices. Microbial-based solutions may prove an effective, low-cost mode for reducing Striga parasitism in sub-Saharan Africa. Here, we demonstrate that the microbiome component of a field soil suppresses Striga infection of sorghum. Potential mechanisms underlying the soil microbiome’s influence on the host plant include root endodermal suberization and aerenchyma formation. Moreover, we observed a depletion of haustorium inducing factors, compounds essential for Striga to establish the host-parasite association, in root exudates collected from sorghum grown in the presence of the soil microbiome as compared to sterile conditions. We further identified individual microbial taxa associated with reduced Striga infection via changes in root cellular anatomy and differentiation as well as in exudate composition. Our study identifies a suite of traits that can be harnessed by individual microbial isolates or their consortia to induce Striga resistance. Combining microbes that elicit Striga resistance directly (affecting the parasite) via repression of haustorium formation with those that act indirectly (affecting the host), by reducing of Striga penetration through root tissue, can broaden the effectiveness of microbe-induced protection from Striga.