ABSTRACT: Investigate the function of RNLs in transcriptional reprogramming during Pf0-1-induced PTI and ETI, using time-resolved transcriptomics. To do so we subjected Col-0, adr1 triple, nrg1.1 nrg1.2 and helperless mutants to infections with Pf0-EV (RNL-(in)dependent PTI), Pf0-AvrRps4 (fully RNL-dependent ETI + PTI), Pf0-AvrRpt2 (partial RNL-dependent ETI + PTI) or Pf0-AvrRpm1 (RNL-independent ETI + PTI).
Project description:We observed inhibition of the hypersensitive response (a typical ETI response) by PTI signaling in an Arabidopsis quadruple mutant dde2 ein2 pad4 sid2 (quad). Thus, we designed an experiment to see the interaction between ETI and PTI signaling at the transcriptome level. The Arabidopsis line dde2 ein2 pad4 sid2 Ed-AvrRpt2 (quadAvrRpt2) was used (Ed-AvrRpt2, estradiol-inducible AvrRpt2 transgene). In this plant line, ETI can be elicited by estradiol (Ed) treatment via in planta expression of AvrRpt2. Transcriptome responses to PTI only, ETI only, and PTI+ETI together were recorded.
Project description:Effector-Triggered Immunity (ETI) and Pattern-Triggered Immunity (PTI) are well-defined modes of plant immunity triggered by recognition of pathogen effector proteins and microbe-associated molecular patterns, respectively. While ETI and PTI network extensively share signaling components, the shared components are used in different ways, resulting in distinct network properties in the model plant Arabidopsis: immunity is highly robust against network perturbations in ETI but relatively sensitive in PTI. However, the molecular mechanism how the shared network leads to the different properties is not known. Here we show that salicylic acid (SA) reponsive genes can respond in the absense of SA during ETI. A 24 DNA microarray study using total RNA from Arabidopsis wildtype Col-0 and sid2-2 mutant infected with Pto hrcC-, Pto EV, Pto AvrRpt2 or water.
Project description:Gene expression profiles of a single Arabidopsis genotype (Col-0) in response to isogenic Pseudomonas syringae strains expressing one of four different cloned avr genes was studied (avrRpt2, avrRpm1, avrPphB, avrRps4; responses mediated by the R genes RPS2, RPM1, RPS5 and RPS4 ).
Project description:Plants deploy cell surface and intracellular leucine rich-repeat domain (LRR) immune receptors to detect pathogens. LRR receptor kinases (LRR-RKs) and LRR receptor proteins (LRR-RPs) recognise microbe-derived molecules to elicit pattern-triggered immunity (PTI), whereas nucleotide-binding LRR (NLR) proteins detect microbial effectors inside cells to confer effector-triggered immunity (ETI). Although PTI and ETI are initiated in different host cell compartments, they rely on the transcriptional activation of similar sets of genes, suggesting pathway convergence upstream of nuclear events. We report that PTI triggered by Arabidopsis LRR-RP (RLP23) requires signalling-competent dimers of the lipase-like proteins EDS1 and PAD4, and ADR1-family helper NLRs, which are all components of ETI. The cell surface LRR-RK SOBIR1 links RLP23 with EDS1, PAD4 and ADR1 proteins, suggesting formation of constitutive supramolecular complexes containing PTI receptors and transducers at the inner side of the plasma membrane.
Project description:Purpose: The goal of this study is to demonstrate the global expression profile of Arabidopsis wild type and PRR mutant plants in response to PTI- and ETI-eliciting strains of Pseudomonas syringae pv tomato (Pst) bacterium. Methods: Four-week-old Arabidopsis plant leaves were infiltrated with sterile water (Mock) or different Pst strains and harvested at 3h or 6h after infiltration for RNA extraction and deep sequencing by Illumina. Raw data were cleaned up and trimmed and reads were mapped to Arabidopsis genome. Gene expression levels were calculated using the TPM method (Transcripts per Kb of exon model per Million mapped reads). Results and Conclusions: This study showed that Pst DC3000 D36E and D36E(avrRpt2) strains both induced significant gene expression changes (with changes of more than 3000 and 7000 genes respectively) in Col-0 plant, and D36E(avrRpt2) strain induced stronger expression changes globally. Furthermore, many genes are differentially regulated in the PRR mutant plants in response to D36E inoculation compared with wild type plant; however, D36E(avrRpt2) inoculation induced very similar expression patterns in two genotypes, suggesting that ETI can largely restore PTI-associated gene expression in the PRR mutant plant. In addition, we also found that ETI can largely induce the expression levels of many key PTI signaling components.
Project description:Effector-Triggered Immunity (ETI) and Pattern-Triggered Immunity (PTI) are well-defined modes of plant immunity triggered by recognition of pathogen effector proteins and microbe-associated molecular patterns, respectively. While ETI and PTI network extensively share signaling components, the shared components are used in different ways, resulting in distinct network properties in the model plant Arabidopsis: immunity is highly robust against network perturbations in ETI but relatively sensitive in PTI. However, the molecular mechanism how the shared network leads to the different properties is not known. Here we show that sustained MAPK activation compensate salicylic acid (SA) signaling. A 12 DNA microarray study using total RNA from Arabidopsis transgenic plants carrying DEX-inducible MKK4DD in Col or sid2-2 background treated with DEX or control.
Project description:Effector-Triggered Immunity (ETI) and Pattern-Triggered Immunity (PTI) are well-defined modes of plant immunity triggered by recognition of pathogen effector proteins and microbe-associated molecular patterns, respectively. While ETI and PTI network extensively share signaling components, the shared components are used in different ways, resulting in distinct network properties in the model plant Arabidopsis: immunity is highly robust against network perturbations in ETI but relatively sensitive in PTI. However, the molecular mechanism how the shared network leads to the different properties is not known. Here we show that salicylic acid (SA) reponsive genes can respond in the absense of SA during ETI.
Project description:Effector-Triggered Immunity (ETI) and Pattern-Triggered Immunity (PTI) are well-defined modes of plant immunity triggered by recognition of pathogen effector proteins and microbe-associated molecular patterns, respectively. While ETI and PTI network extensively share signaling components, the shared components are used in different ways, resulting in distinct network properties in the model plant Arabidopsis: immunity is highly robust against network perturbations in ETI but relatively sensitive in PTI. However, the molecular mechanism how the shared network leads to the different properties is not known. Here we show that sustained MAPK activation compensate salicylic acid (SA) signaling.
Project description:We designed an experiment to assess ETI and PTI in RG-PtoR using a series of Pst DC3000 strains which have different mutations that allow dissection of the plant immune response. We collected samples at 6 hai and monitored the development of disease in these plants. Plants infiltrated with DC3000 ΔfliC had no disease symptoms due to the recognition of AvrPto and AvrPtoB effectors by Pto. In contrast, when these two effectors were absent, the plants developed speck disease (DC3000 ΔavrPto ΔavrPtoB and DC3000 ΔavrPto ΔavrPtoB ΔfliC strains). Plants infiltrated with the triple mutant showed the greatest disease severity due to the absence of ETI and flagellin-activated PTI induction. This experimental design allowed us to identify gene expression changes associated with flagellin-activated PTI (DC3000 ΔavrPto ΔavrPtoB versus DC3000 ΔavrPto ΔavrPtoB ΔfliC) and Pto/Prf-mediated ETI (DC3000 ΔfliC versus DC3000 ΔavrPto ΔavrPtoB ΔfliC). NOTE: Samples in SRA were assigned the same sample accession. This is incorrect as there are different samples, hence 'Source Name' was replaced with new values. Comment[ENA_SAMPLE] contains the original SRA sample accessions.
Project description:Plants have evolved a two-layered immune system that mainly includes pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) against pathogen attack. PTI and ETI signaling are functionally linked, but also distinct due to specific perceived ligands and activation modes. Unraveling how PTI and ETI coordinate the immune responses against pathogens is crucial for understanding the regulatory mechanisms in plant immunity. To better understand the protein profiling and phosphorylation events during PTI and ETI, we employed integrated whole proteome and phosphoproteome analyses in the tomato-Pst pathosystem with different Pst DC3000 mutants that allow dissection of different layers of immune responses. A total of 225 proteins and 79 phosphopeptides were differentially regulated in tomato leaves during immune responses. Our proteomics results indicate that some overlapping immune responses are triggered by both PTI and ETI-inducing treatment, and ETI response is more robust than PTI response for most proteins. The change patterns of protein abundance and phosphorylation revealed some key regulators involved in Ca2+ signaling, mitogen-activated protein kinase cascades, and reversible protein phosphorylation, ROS and redox homeostasis, direct defense, transcription machinery and protein turnover, cell wall remodeling, hormone biosynthesis, as well as immune molecule accumulation, are modulated during PTI and/or ETI, suggesting their common or specific roles in plant immune responses. However, NAC domain protein and lipid particle serine esterase, two PTI-specific genes from previous transcriptomic work, have not been detected as differentially regulated in our proteomic analysis, and they were proved to be not PTI-specific inducible and therefore cannot be used as PTI-reporters through “overlapping circle” pattern assay. These results provide insights into the fine-tuned regulatory mechanisms between PTI and ETI in-Pst pathosystem, which will springboard further investigations into the sophisticated mechanisms in plant immunity.