Analysis of gene expression in Arabidopsis thaliana after priming with BABA and infection with Pseudomonas syringae pv tomato DC3000
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ABSTRACT: Arabidopsis thaliana (Col-0) plants were treated with BABA and gene expression differences to control plants were monitored after dip-inoculation with Pseudomonas syringae pv tomato DC3000. Keywords: transcript profiling, response to BABA-induced priming and infection 3 independant replicates were analyzed by two color co-hybridizations. Leaf RNA from Pseudomonas infected control plants (Cy3 labeled cDNA) was cohybridized with leaf RNA from Pseudomonas infected BABA pretreated plants (Cy5 labeled cDNA). Samples were collected 22 hours after bacterial inoculation. BABA pretreatment was performed two days before bacterial inoculation. To assess the effect of BABA alone on gene expression, leaf RNA from BABA treated plants (Cy5 labeled cDNA) was cohybridized with leaf RNA (Cy3 labeled cDNA) from water treated plants.
Project description:Arabidopsis thaliana (Col-0) plants were treated with BABA and gene expression differences to control plants were monitored after dip-inoculation with Pseudomonas syringae pv tomato DC3000. Keywords: transcript profiling, response to BABA-induced priming and infection
Project description:Beta-amino butyric acid (BABA) is an endogenous stress signalling molecule in plants. External application (e.g. by soil-drenching) of BABA induces high levels of resistance in Arabidopsis (and other plants) against the oomycete pathogen Hyaloperonospora arabidopsidis. However, high doses of BABA also trigger a metabolic stress response and stunt plant growth. Perception of BABA is mediated by the protein IBI1. The ibi1-1 mutant is deficient in BABA-induced resistance, but hypersensitive to BABA-induced stress. To identify pathways that contribute to BABA-induced resistance and stress, respectively, we compared the transcriptome of Arabidopsis wild-type and ibi1-1 mutant plants after pre-treatment with water or BABA, followed by inoculation with Hyaloperonospora arabidopsidis (or mock).
Project description:Exposure of plants to stress conditions or to certain chemical elicitors can establish a primed state, whereby responses to future stress encounters are enhanced. Stress priming can be long-lasting and likely involves epigenetic regulation of stress-responsive gene expression. However, the molecular events underlying priming are not well understood. Here, we characterise epigenetic changes in tomato plants primed for pathogen resistance by treatment with β-aminobutyric acid (BABA). We used whole genome bisulphite sequencing to construct tomato methylomes from control plants and plants treated with BABA at the seedling stage, and a parallel transcriptome analysis to identify genes primed for the response to inoculation by the fungal pathogen, Botrytis cinerea. Genomes of plants treated with BABA showed a significant reduction in global cytosine methylation, especially in CHH sequence contexts. Analysis of differentially methylated regions (DMRs) revealed that CHH DMRs were almost exclusively hypomethylated and were enriched in gene promoters and in DNA transposons located in the chromosome arms. Although there was some enrichment of stress response-related gene ontology terms in genes overlapping CHH DMRs, there was no significant enrichment of DMRs amongst a set of 747 primed defence genes, and nor was the pattern of methylation in these genes altered by BABA treatment. Hence, we conclude that whilst BABA treatment of tomato seedlings results in characteristic changes in genome-wide DNA methylation, CHH hypomethylation does not appear to directly target genes showing primed responses to pathogen infection. Instead, methylation may confer priming via in-trans regulation, acting at a distance from defence genes, and/or by targeting a smaller group of regulatory genes controlling stress responses.
Project description:Prior exposure to microbial-associated molecular patterns or specific chemical compounds can promote plants into a primed state with stronger defence responses. b-aminobutyric acid (BABA) is an endogenous stress metabolite that induces resistance protecting various plants towards diverse stresses. In this study, by integrating BABA-induced changes in selected metabolites with transcriptome and proteome data, we generated a global map of the molecular processes operating in BABA-induced resistance (BABA-IR) in tomato. BABA significantly restricts the growth of the pathogens Oidium neolycopersici and Phytophthora parasitica but not Botrytis cinerea. A cluster analysis of the upregulated processes showed that BABA acts mainly as a stress factor in tomato. The main factor distinguishing BABA-IR from other stress conditions was the extensive induction of signalling and perception machinery playing a key role in defence priming. Interestingly, the signalling processes and immune response activated during BABA-IR in tomato differed from those in Arabidopsis with substantial enrichment of genes associated with jasmonic acid and ethylene signalling and no change in Asp levels. Our results revealed key differences between the effect of BABA on tomato and other model plants studied until now. Surprisingly, salicylic acid is not involved in BABA downstream signalization whereas ethylene and jasmonic acid play a crucial role.
Project description:RNA from 11 individual mouse cell lines were reverse-transcribed to cDNA, labeled with Cy5 and cohybridized with Cy3-labeled UMRR onto 7,500-spot mouse oligo microarrays (UNC). The data was analyzed using GeneTraffic software. 300-1000 spots out of 8,000 were flagged on each microarray and excluded from further analysis. Spots with hybridization signals in Cy5 channel higher than 1000 and with Cy5/Cy3 ratio greater than 2 were collected and the number of spots with these characteristics on only one microarray was determined. A reference experiment design type is where all samples are compared to a common reference. Keywords: reference_design
Project description:Summary: The non-protein amino acid beta-aminobutyric acid (BABA) primes Arabidopsis to respond more quickly and strongly to pathogen and osmotic stress. Here, we report that BABA also significantly enhanced acquired thermotolerance in Arabidopsis. This thermotolerance was dependent on heat shock protein 101, a critical component of the normal heat shock response. BABA did not enhance basal thermotolerance under a severe heat shock treatment. No roles for the hormones ethylene and salicylic acid in BABA-induced acquired thermotolerance were identified by mutant analysis. By global gene expression analysis, transcript levels for several transcription factors and DNA binding proteins regulating responses to the stress hormone abscisic acid (ABA) were found to be elevated in BABA-treated relative to water-treated plants. The role of ABA in BABA-induced thermotolerance was complex. BABA-enhanced thermotolerance was partially compromised in the ABA-insensitive mutant, abi1-1, but was augmented in abi2-1. In an unrelated process, BABA, like ABA, inhibited root growth and the level of inhibition was roughly additive in roots treated with both compounds. Root growth of both abi1-1 and abi2-1 was also inhibited by BABA. Unexpectedly, abi1-1 and abi2-1 root growth was inhibited more strongly by combined ABA and BABA treatments than by BABA alone. Our results together with previously published data suggest that BABA is a general enhancer of plant stress resistance and that cross-talk occurs between BABA and ABA signalling cascades. Specifically, the BABA-mediated accumulation of ABA transcription factors without concomitant activation of a downstream ABA response could represent one component of the BABA-primed state in Arabidopsis. Overall design: A replicate experimental design type is where a series of replicates are performed to evaluate reproducibility or as a pilot study to determine the appropriate number of replicates for a subsequent experiments. Arabidopsis Col-0 plants were grown in ProMix HP (Premier Horticulture, Red Hill, PA, USA) for 14 days and the soil was drenched with a 0.25 mM BABA solution 1 day prior to harvesting samples for RNA preparation. These plants were grown in a growth chamber at 21?C with a 14-hr photoperiod. All plants were grown at a light intensity of about 100 ? 150 ?E m-2 s-1. BABA (mixed isomers, Sigma, Milwaukee, WI, USA) was diluted in water at indicated concentration. A biological sample represents a comparison between plants that were water-treated (green channel) to plants drenched with BABA (red channel). This study represents 4 independent biological replicates. Computed
Project description:A comparative study to determine the pepper leaf curl virus resistance machanism between resistant and susceptible genotypes at three leaf stage. To study the molecular mechanism of pepper leaf curl virus (PepLCV) resistance, pepper plants were exposed to PepLCV through artificial inoculation and hybridization on Agilent tomato microarrays. The expression analysis of PepLCV resistant and susceptible genotypes after artificial inoculation at three leaf stage showed that the resistance against PepLCV is due to sum of expression of hundreds of genes at a particular stage.
Project description:Japonica rice (Oryza sativa ssp. japonica) variety Mudanjiang 8 (MDJ8) is the wild-type and is susceptible to Xoo. Transgenic rice line Rb49 carries the MR gene Xa3/Xa26, which is driven by its native promoter with the genetic background of MDJ8, and this line is resistant to certain strains (including strain PXO61) of Xoo. Although many studies on Xa3/Xa26-mediated resistace to rice Xoo have been published, the molecular mechanism of this major resistance gene remains poorly understood. Here, we use affymetrix microarray technology to analyze the regulated network mediated by Xa3/Xa26 We used microarrays to study the gene expression network mediated by Xa3/Xa26. Plants were inoculated with the Xoo strain PXO61 at the four-leaf to five-leaf stage by the leaf-clipping method. Control rice plants were inoculated with water (mock inoculation). Samples were collected before inoculation (ck) and at 2, 4, and 24 hours after PXO61 or mock inoculation from Rb49 and MDJ8. Leaf fragments approximately 2 cm in length that were immediately next to the inoculation site were collected.
Project description:Leaves are colonised by a complex mix of microbes, termed the leaf microbiota. Even though the leaf microbiota is increasingly recognised as an integral part of plant life and health, our understanding of its interactions with the plant host is still limited. Here, mature, axenically grown Arabidopsis thaliana plants were spray-inoculated with diverse leaf-colonising bacteria. Whole transcriptome sequencing revealed that four days after inoculation, leaf transcriptional changes to colonisation by non-pathogenic and pathogenic bacteria differed in strength but not in the type of response. Inoculation of plants with different densities of the non-pathogenic bacterium Williamsia sp. Leaf354 showed that high bacterial titers caused disease phenotypes and led to severe transcriptional reprogramming with a strong focus on plant defence. This SuperSeries is composed of the SubSeries listed below.
Project description:Induced resistance responses of plants to biotic stress can be enhanced by prior treatment by chemical priming agents such as beta-aminobutyric acid (BABA). Defence-related genes are typically not expressed following priming, but show faster and/or stronger induced expression following infection. Here we test the transcriptome responses of control and BABA-primed plants to infection with the fungal pathogen Botrytis cinerea.