Project description:Investigation of the phylogenetic diversity of Acidobacteria taxa using PCR amplicons from positive control 16S rRNA templates and total genomic DNA extracted from soil and a soil clay fraction
Project description:Comparison of probe-target dissociations of probe Eub338 and Gam42a with native RNA of P. putida, in vitro transcribed 16s rRNA of P. putida, in vitro transcribed 16S rRNA of a 2,4,6-trinitrotoluene contaminated soil and an uncontaminated soil sample. Functional ANOVA revealed no significant differences in the dissociation curves of probe Eub338 when hybridised to the different samples. On the opposite, the dissociation curve of probe Gam42a with native RNA of P. putida was significantly different than the dissociation curves obtained with in vitro transcribed 16S rRNA samples. Keywords: Microbial diversity, thermal dissociation analysis, CodeLink microarray
Project description:Investigation of the phylogenetic diversity of Acidobacteria taxa using PCR amplicons from positive control 16S rRNA templates and total genomic DNA extracted from soil and a soil clay fraction A ten chip study using PCR amplicons from cloned 16S rRNA genes and from diverse soil 16S rRNAs, with PCR primers specific to the Division Acidobacteria. Each chip measures the signal from 42,194 probes (in triplicate) targeting Acidobacteria division, subdivision, and subclades as well as other bacterial phyla. All samples except one (GSM464591) include 2.5 M betaine in the hybridization buffer. Pair files lost due to a computer crash.
Project description:Asymptomatic plants grown in natural soil are colonized by phylogenetically structured communities of microbes known as the microbiota. Individual microbiota members can activate host innate immunity, which limits pathogen proliferation and curtails plant growth, a phenomenon known as the growth-defense trade-off. We report that in mono-associations, 41% (62/151) of taxonomically diverse root commensals suppress Arabidopsis root growth inhibition (RGI) triggered by immune-stimulating microbe-/damage-associated molecular patterns. 16S rRNA gene amplicon sequencing data reveal that immune activation alters the profile of synthetic communities (SynComs) comprised of RGI non-suppressive strains, while the presence of RGI-suppressive strains attenuates this effect. Chronic root transcriptional outputs in response to colonization with RGI-suppressive or non-suppressive SynComs share a core of genes with a stereotyped expression pattern. However, RGI-suppressive SynComs specifically downregulate a subset of immune-related genes. Such SynCom-specific modulation of defense is physiologically relevant as mutation of one commensal-downregulated transcription factor, MYB15, or pre-colonization with an RGI-suppressive SynCom render plants more susceptible to opportunistic Pseudomonas pathogens. Our results suggest that commensals with contrasting MTI modulating capacities interact with the plant host and together buffer the system against pathogen challenge, defense-associated plant growth inhibition and community shift via a crosstalk with the immune system, leading to commensal-host homeostasis.
Project description:Asymptomatic plants grown in natural soil are colonized by phylogenetically structured communities of microbes known as the microbiota. Individual microbes can activate microbe-associated molecular pattern (MAMP)-triggered immunity (MTI), which limits pathogen proliferation but curtails plant growth, a phenomenon known as the growth-defense trade-off. We report that in mono-associations, 41% (62/151) of taxonomically diverse root bacteria commensals suppress Arabidopsis thaliana root growth inhibition (RGI) triggered by immune-stimulating MAMPs or damage-associated molecular patterns. Amplicon sequencing of bacteria 16S rRNA genes reveal that immune activation alters the profile of synthetic communities (SynComs) comprised of RGI-non-suppressive strains, while the presence of RGI-suppressive strains attenuates this effect. Root colonization by SynComs with different complexities and RGI-suppressive activities alters the expression of 174 core host genes with functions related to root development and nutrient transport. Further, RGI-suppressive SynComs specifically downregulate a subset of immune-related genes. Mutation of one commensal-downregulated transcription factor, MYB15, or pre-colonization with RGI-suppressive SynComs render plants more susceptible to opportunistic Pseudomonas pathogens. Our results suggest that RGI-non-suppressive and suppressive root commensals modulate host susceptibility to pathogens by either eliciting or dampening MTI responses, respectively. This interplay buffers the plant immune system against pathogen perturbation and defense-associated growth inhibition, ultimately leading to commensal-host homeostasis.