Project description:Schengen-pathway modulates the phenylpropanoid pathway and induces defense-related mechanisms
2020-11-01 | GSE158809 | GEO
Project description:Transcriptome profiling reveals GABA role in alleviating chilling injury in Pitaya through regulation of phenylpropanoid pathways, antioxidant defense, and phytohormone signaling
Project description:Piriformospora indica, an endophytic fungus of Sebacinales, colonizes the roots of many plant species including Arabidopsis thaliana. The symbiotic interaction promotes plant per-formance, growth and resistance/tolerance against abiotic and biotic stress. We demonstrate that exudated compounds from the fungus activate stress and defense responses in the Arabidopsis roots and shoots before the two partners are in physical contact. They induce stomata closure, stimulate reactive oxygen species (ROS) production, stress-related phytohormone accumulation and activate defense and stress genes in the roots and/or shoots. Once a physical contact is established, the stomata re-open, ROS and phytohormone levels decline, and the gene expression pattern indicates a shift from defense to mutualistic interaction. We propose that exudated compounds from P. indica induce stress and defense responses in the host. Root colonization results in the downregulation of defense responses and the activation of genes involved in promoting plant growth, metabolism and performance.
Project description:Arabidopsis thaliana plants fend off insect attack by constitutive and inducible production of toxic metabolites such as glucosinolates (GS). A triple mutant lacking MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that are known to additively control jasmonate-related defense responses, is highly susceptible to insect herbivory. In this study, we performed a whole-genome microarray analysis on three-week-old plants and compared wild-type (Col-0) and myc2myc3myc4 plants in control conditions (no treatment). Myc234 was shown to have a highly reduced expression of GS biosynthesis genes.
Project description:MYC2 is a central node controlling the crosstalk between JA and other phytohormone signalling pathways and regulating responses to light and circadian clock. We hypothesized that this transcription factor might coordinate prioritization of microbiota-induced growth over defense under suboptimal light conditions
Project description:Piriformospora indica, an endophytic fungus of Sebacinales, colonizes the roots of many plant species including Arabidopsis thaliana. The symbiotic interaction promotes plant per-formance, growth and resistance/tolerance against abiotic and biotic stress. We demonstrate that exudated compounds from the fungus activate stress and defense responses in the Arabidopsis roots and shoots before the two partners are in physical contact. They induce stomata closure, stimulate reactive oxygen species (ROS) production, stress-related phytohormone accumulation and activate defense and stress genes in the roots and/or shoots. Once a physical contact is established, the stomata re-open, ROS and phytohormone levels decline, and the gene expression pattern indicates a shift from defense to mutualistic interaction. We propose that exudated compounds from P. indica induce stress and defense responses in the host. Root colonization results in the downregulation of defense responses and the activation of genes involved in promoting plant growth, metabolism and performance. Twelve day-old (48 h cold treatment and 10 days of illumination) Arabidopsis seedlings of equal sizes were selected for co-cultivation experiments. They were transferred to PNM plates with a nylone membrane on the top (Johnson et al. 2011) and exposed to a fungal plug 5 mm in diameter or a KM plug of the same size without fungal hyphae (control). The plugs were placed 3 cm away from the closest root part . The light intensity (80 ± 5 μmol m-2 sec-1) was checked every third day to ensure that both P. indica- and mock-treated seedlings receive equal amounts of light.
Project description:Next-generation sequencing (NGS)-derived transcriptomic profiling was carried out to compare the transcriptomic changes mediated by COMT knockout in U87 cells. We found significant enrichment of gene signatures involving IFNa/b signaling in COMT-KO U87 cells compared to control cells. Our analysis also demonstrated that COMT deficiency interferes with mitochondrial functions and induces the expression of genes associated with the anti-viral RNA sensing pathway.
Project description:A comparative transcriptomic analysis of the responses arising 24 hours after infection of the susceptible T. aestivum variety ‘Fielder’, by Fg with co-application of either abscisic acid (ABA), gibberellic acid (GA) or the ABA-signaling inhibitor AS6, compared to stand-alone treatments is reported. Relevance of transcriptomic responses were assessed by differential expression feature evaluations (DEFE), highlighting that co-applied GA elicits a relatively strong opposing influence on Fg modulated genes, while co-applied ABA elicits similar responses to Fg. Co-applied AS6 elicited an opposing effect on gene regulation compared to co-applied ABA, and based on its lack of biological effect, was instrumental in reducing the identity of genes relevant to eliciting ABA and GA effects, to a subset of genes, largely defined within four DEFE patterns. A more targeted investigation of the impact of the co-applied conditions with respect to plant phytohormone biosynthesis and signaling pathways, correlated with select phytohormone profiles, confirmed activation of the ABA and GA pathways. Further analyses highlighted a novel interaction, potentially representing cross-talk, between co-applied ABA and the brassinosteroid signaling pathway. Additional responses within the classical defense hormone pathways as well as auxin and cytokinin pathways were found to correlate with expected defense responses. Togther these results yield insight into a range of mechanisms potentially underlying the observed contributions of ABA and GA to wheat susceptibility and resistance respectively to Fg, raising novel hypotheses for consideration in the development of FHB resistant wheat lines and agronomic practices in the longer term.
Project description:To better understand the role of phenylpropanoid pathway perturbation in plant metabolism, Populus tremuloides cell cultures previously established from leaf mesophyll tissue were fed with methyl jasmonate, alpha-aminooxy-beta-phenylpropionic acid (AOPP), or both approximately 5 days after transfer to fresh medium. Methyl jasmonate is an elicitor that activates a suite of defense responses including phenylpropanoid metabolism. In contrast, AOPP acts as an inhibitor of phenylalanine ammonia lyase (PAL). Samples were harvested 48 hrs after initiation of the experiment. Total RNA was extracted and gene expression measured using Affymetrix poplar genome microarrays.
Project description:Phytophthora cinnamomi Rands (Pc) is a hemibiotrophic oomycete and the causal agent of Phytophthora root rot (PRR) of the commercially important fruit crop avocado (Persea americana Mill.). Plant defense against pathogens is modulated by phytohormone signaling pathways such as salicylic acid (SA), jasmonic acid (JA), ethylene (ET), auxin and abscisic acid. The role of specific signaling pathways induced and regulated during hemibiotroph-plant interactions has been widely debated. Some studies report SA mediated defense while others hypothesize that JA responses restrict the spread of pathogens. This study aimed to identify the role of SA- and JA- associated genes in the defense strategy of a resistant avocado rootstock, Dusa® in response to Pc infection. Transcripts associated with SA-mediated defense pathways and lignin biosynthesis were upregulated at 6 hours post-inoculation (hpi). Results suggest that auxin, reactive oxygen species (ROS) and Ca2+ signaling was also important during this early time point, while JA signaling was absent. Both SA and JA defense responses were shown to play a role during defense at 18 hpi. Induction of genes associated with ROS detoxification and cell wall digestion (β-1-3-glucanase) was also observed. Most genes induced at 24 hpi were linked to JA responses. Other processes at play in avocado at 24 hpi include cell wall strengthening, the formation of phenolics and induction of arabinogalactan, a gene linked to Pc zoospore immobility. This study represents the first transcriptome wide analysis of a resistant avocado rootstock treated with SA and JA compared to Pc infection. The results provide evidence of a biphasic defense response against the hemibiotroph, which initially involves SA-mediated gene expression followed by the enrichment of JA-mediated defense from 18 to 24 hpi. Genes and molecular pathways linked to Pc resistance are highlighted and may serve as future targets for manipulation in the development of PRR resistant avocado rootstocks.