Project description:ra04-07_pgpr - profiling of the pgpr induced systemic resistance (isr) - Experiment 1 : Which genes are up- or down-regulated in Arabidopsis thaliana cultivated in vitro with increased lateral root development in response to Phyllobacterium STM196 inoculation. Experiment 2 : Which genes are up- or down-regulated during the ISR triggered by a rhizobacteria, in comparison with those affected by a pathogenic interaction. Experiment 3 : which genes are specifically induced or repressed in Arabidopsis thaliana by inoculation of the soil with a PGPR vs a bacteria that has the ability to trigger nodule formation in a Legume. - Seeds were sawn on 0.8% (W/V) agar mineral medium (see below). 4 days after storage in the dark at 4degreeC, seedling were cultivated 6 days in a growth chamber (16 h daily, 20-22degreeC) and then transferred on soil inoculated or not with 107 cfu.g-1 of Bradyrhizobium strain ORS278. Three weeks later, 3 leaves per plant were infiltrated with a suspension of Pseudomonas syringae pv. tomato (2.105 cfu.ml-1) or with MgSO4 10 mM alone for control plants. Infiltrated leaves were collected 24h later. Keywords: normal vs rnai mutant comparaison,treated vs untreated comparison
Project description:ra04-07_pgpr - profiling of the root architecture response to phyllobacterium - Experiment 1 : Which genes are up- or down-regulated in Arabidopsis thaliana cultivated in vitro with increased lateral root development in response to Phyllobacterium STM196 inoculation. Experiment 2 : Which genes are up- or down-regulated during the ISR triggered by a rhizobacteria, in comparison with those affected by a pathogenic interaction. Experiment 3 : which genes are specifically induced or repressed in Arabidopsis thaliana by inoculation of the soil with a PGPR vs a bacteria that has the ability to trigger nodule formation in a Legume. - Seeds of wild-type Arabidopsis thaliana (ecotype Columbia) were surface-sterilized and sawn on agar mineral medium (see below). 4 days after storage in the dark at 4degreeC, seedling were cultivated 6 days in a growth chamber (16 h daily, 20-22degreeC) and then transferred on a fresh agar mineral medium inoculated or not with Phyllobacterium STM196 (2.108 cfu/ml). 6 days later, root and leaves were collected, froze on liquid nitrogen and stored at -80degreeC. Keywords: treated vs untreated comparison
Project description:⢠Selected soil-borne rhizobacteria can trigger an induced systemic resistance (ISR) that is effective against a broad spectrum of pathogens. In Arabidopsis thaliana, the root-specific transcription factor MYB72 is required for the onset of ISR, but is also associated with plant survival under conditions of iron deficiency. Here we investigated the role of MYB72 in both processes. ⢠To identify MYB72 target genes, we analyzed the root transcriptomes of wild-type Col-0, mutant myb72, and complemented 35S:FLAG-MYB72/myb72 plants in response to ISR-inducing Pseudomonas fluorescens WCS417. ⢠Five WCS417-inducible genes were misregulated in myb72 and complemented in 35S:FLAG-MYB72/myb72. Amongst these, we uncovered β-glucosidase BGLU42 as a novel component of the ISR signaling pathway. Overexpression of BGLU42 resulted in constitutive disease resistance, whereas bglu42 was defective in ISR. Furthermore, we found 195 genes to be constitutively upregulated in MYB72-overexpressing roots in the absence of WCS417. Many of these encode enzymes involved in the production of iron-mobilizing phenolic metabolites under conditions of iron deficiency. We provide evidence that BGLU42 is required for their release into the rhizosphere. ⢠Together, this work highlights a thus far unidentified link between the ability of beneficial rhizobacteria to stimulate systemic immunity and mechanisms induced by iron deficiency in host plants. Total 18 samples of RNA extracted from Arabidopsis roots: Three genotypes: 1) Wild-type Arabidopsis thaliana accession Col-0, 2) mutant myb72-2 (Col-0 background), 3) Transgenic 35S:FLAG-MYB72 (oxMYB72) in the myb72-2 background; Two treatments: 1) non-treated control, 2) Roots colonized by beneficial Pseudomonas fluorescens WCS417 rhizobacteria; Replicates: three biological replicates per genotype/treatment combination
Project description:Arabidopsis thaliana transcriptome analysis in response to plant growth promoting rhizobacteria (PGPR)<br> Experiment 1 : Changes in gene expression profile triggered during root architecture response to Phyllobacterium.<br> Biological question : Which genes are up- or down-regulated in Arabidopsis thaliana cultivated in vitro with increased lateral root development in response to Phyllobacterium STM196 inoculation.<br> Experiment description: Seeds of wild-type Arabidopsis thaliana (ecotype Columbia) were surface-sterilized and sown on agar mineral medium (see below). 4 days after storage in the dark at 4C, seedling were cultivated 6 days in a growth chamber (16 h daily, 20-22C) and then transferred on a fresh agar mineral medium inoculated or not with Phyllobacterium STM196 (2.108 cfu/ml). 6 days later, root and leaves were collected, froze on liquid nitrogen and stored at -80C.<br> <br> Experiment 2 : Changes in gene expression profile triggered during induced systemic resistance (ISR)<br> Biological question : Which genes are up- or down-regulated during the ISR triggered by a rhizobacteria, in comparison with those affected by a pathogenic interaction. <br> Experiment description: Seeds were sown on 0.8% (W/V) agar mineral medium (see below). 4 days after storage in the dark at 4C, seedling were cultivated 6 days in a growth chamber (16 h daily, 20-22C) and then transferred on soil inoculated or not with 107 cfu.g-1 of Bradyrhizobium strain ORS278. Three weeks later, 3 leaves per plant were infiltrated with a suspension of Pseudomonas syringae pv. tomato (2.105 cfu.ml-1) or with MgSO4 10 mM alone for control plants. Infiltrated leaves were collected 24h later.<br> <br> Experiment 3 : Comparison of the effects of 3 rhizobacteria on Arabidopsis thaliana transcriptome<br> Biological question : which genes are specifically induced or repressed in Arabidopsis thaliana by inoculation of the soil with a PGPR vs a bacteria that has the ability to trigger nodule formation in a Legume. <br> Experiment description: Seeds of wild-type Arabidopsis thaliana (ecotype Columbia) were surface-sterilized and sown on agar mineral medium. Four days after storage in the dark at 4C, seedlings were cultivated 6 days in a growth chamber (16 h daily, 20-22C) and then transferred on soil inoculated or not with 108 cfu.g-1 of Mesorhizobium loti, or 108 cfu.g-1 of Phyllobacterium STM196, or 107 cfu.g-1 of Bradyrhizobium ORS278.
Project description:ra04-07_pgpr - trancriptional response to 3 rhizobacteria - Experiment 1 : Which genes are up- or down-regulated in Arabidopsis thaliana cultivated in vitro with increased lateral root development in response to Phyllobacterium STM196 inoculation. Experiment 2 : Which genes are up- or down-regulated during the ISR triggered by a rhizobacteria, in comparison with those affected by a pathogenic interaction. Experiment 3 : which genes are specifically induced or repressed in Arabidopsis thaliana by inoculation of the soil with a PGPR vs a bacteria that has the ability to trigger nodule formation in a Legume. - Seeds of wild-type Arabidopsis thaliana (ecotype Columbia) were surface-sterilized and sawn on agar mineral medium. Four days after storage in the dark at 4degreeC, seedlings were cultivated 6 days in a growth chamber (16 h daily, 20-22degreeC) and then transferred on soil inoculated or not with 108 cfu.g-1 of Mesorhizobium loti, or 108 cfu.g-1 of Phyllobacterium STM196, or 107 cfu.g-1 of Bradyrhizobium ORS278. Keywords: treated vs untreated comparison
Project description:• Selected soil-borne rhizobacteria can trigger an induced systemic resistance (ISR) that is effective against a broad spectrum of pathogens. In Arabidopsis thaliana, the root-specific transcription factor MYB72 is required for the onset of ISR, but is also associated with plant survival under conditions of iron deficiency. Here we investigated the role of MYB72 in both processes. • To identify MYB72 target genes, we analyzed the root transcriptomes of wild-type Col-0, mutant myb72, and complemented 35S:FLAG-MYB72/myb72 plants in response to ISR-inducing Pseudomonas fluorescens WCS417. • Five WCS417-inducible genes were misregulated in myb72 and complemented in 35S:FLAG-MYB72/myb72. Amongst these, we uncovered β-glucosidase BGLU42 as a novel component of the ISR signaling pathway. Overexpression of BGLU42 resulted in constitutive disease resistance, whereas bglu42 was defective in ISR. Furthermore, we found 195 genes to be constitutively upregulated in MYB72-overexpressing roots in the absence of WCS417. Many of these encode enzymes involved in the production of iron-mobilizing phenolic metabolites under conditions of iron deficiency. We provide evidence that BGLU42 is required for their release into the rhizosphere. • Together, this work highlights a thus far unidentified link between the ability of beneficial rhizobacteria to stimulate systemic immunity and mechanisms induced by iron deficiency in host plants.
Project description:Plant growth promoting rhizobacteria (PGPR) induce positive effects in plants, such as increased growth or reduced stress susceptibility. The mechanisms behind PGPR/plant interaction are poorly understood, as most studies have described short- term responses on plants and only a few studies have analyzed plant molecular responses under PGPR colonization. Transcriptional profiles were determined by microarray analysis (Affymetrix ATH1 Genome Array) in Arabidopsis thaliana plants inoculated with the PGPR bacterial model Burkholderia phytofirmans PsJN
Project description:Plants have developed a complicated resistance system, and they exhibit various defense patterns in response to different attackers. However, the determine factors of plant defense patterns are still not clear. Here, we hypothesized that damage patterns of plant attackers play an important role in determining the plant defense patterns. To test this hypothesis, we selected leafminer, which has a special feeding pattern more similar to pathogen damage than chewing insects, as our model insect, and Arabidopsis thaliana as the response plants. The local and systemic responses of Arabidopsis thaliana to leafminer feeding were investigated using the Affymetrix ATH1 genome array. Damaged leaves of Arabidopsis thaliana for local damage analysis and the intact leaves on the same plant for systemic damage analysis were separately frozen by liquid nitrogen. Then, we used an Affymetrix ATH1 Arabidopsis microarray to study the expression changes pattern of Arabidopsis thaliana to pea leafminers damage, both locally (LI) and systemically (SI). We downloaded data from the web database and used hierarchical clustering to explore the relationships of Arabidopsis thaliana expression pattern to different kinds of attackers.