Project description:Salicylic acid (SA) is a critical molecule mediating plant innate immunity with an important role limiting the growth and reproduction of the virulent powdery mildew (PM) Golovinomyces orontii on Arabidopsis thaliana. To investigate this later phase of the PM interaction, and the role played by SA, we performed replicated global expression profiling for wild type and SA biosynthetic mutant ics1 Arabidopsis from 0 to 7 days post infection. We found that ICS1-impacted genes comprise 3.8% of profiled genes with known molecular markers of Arabidopsis defense ranked very highly by the multivariate empirical Bayes statistic (T2 statistic ((Tai and Speed, 2006)). Functional analyses of T2-selected genes identified statistically significant PM-impacted processes including photosynthesis, cell wall modification, and alkaloid metabolism that are ICS1-independent. ICS1-impacted processes include redox, vacuolar transport/secretion, and signaling. Our data also supports a role for ICS1 (SA) in iron and calcium homeostasis and identifies components of SA crosstalk with other phytohormones. Through our analysis, 39 novel PM–impacted transcriptional regulators were identified. Insertion mutants in one of these regulators, PUX2, results in significantly reduced reproduction of the powdery mildew in a cell death independent manner. Though little is known about PUX2, PUX1 acts as a negative regulator of Arabidopsis CDC48 (Rancour et al., 2004; Park et al., 2007), an essential AAA-ATPase chaperone that mediates diverse cellular activities including homotypic fusion of ER and Golgi membranes, ER-associated protein degradation, cell cycle progression, and apoptosis. Future work will elucidate the functional role of the novel regulator PUX2 in PM resistance. Keywords: time course, pathogen response
Project description:In plants, the activation of immunity is often inversely correlated with growth. Mechanisms that plant growth in the context of pathogen challenge and immunity are unclear. Investigating Arabidopsis infection with the powdery mildew fungus, we find that the Arabidopsis atypical E2F DEL1, a transcriptional repressor known to promote cell proliferation, represses accumulation of the hormone salicylic acid (SA), an established regulator of plant immunity. DEL1 deficient plants are more resistant to pathogens and slightly smaller than wild type. The resistance and size phenotypes of DEL1 deficient plants are due to the induction of SA and activation of immunity in the absence of pathogen challenge. Moreover, Enhanced Disease Susceptibility 5 (EDS5), a SA transporter required for elevated SA and immunity, is a direct repressed target of DEL1. Together, these findings indicate that DEL1 control of SA levels contributes to regulating the balance between growth and immunity in developing leaves.
Project description:LC-MS/MS data were collected from uninfected and parallel Golovinomyces orontii MGH1- infected Arabidopsis thaliana leaf tissue (leaves 7-9) at 12 days post inoculation to understand the manipulation of host lipid metabolism by the powdery mildew.
Project description:In plants, the activation of immunity is often inversely correlated with growth. Mechanisms that plant growth in the context of pathogen challenge and immunity are unclear. Investigating Arabidopsis infection with the powdery mildew fungus, we find that the Arabidopsis atypical E2F DEL1, a transcriptional repressor known to promote cell proliferation, represses accumulation of the hormone salicylic acid (SA), an established regulator of plant immunity. DEL1 deficient plants are more resistant to pathogens and slightly smaller than wild type. The resistance and size phenotypes of DEL1 deficient plants are due to the induction of SA and activation of immunity in the absence of pathogen challenge. Moreover, Enhanced Disease Susceptibility 5 (EDS5), a SA transporter required for elevated SA and immunity, is a direct repressed target of DEL1. Together, these findings indicate that DEL1 control of SA levels contributes to regulating the balance between growth and immunity in developing leaves. Mature, fully expanded leaves of 41/2-week-old Col-0 and del1-1 plants were harvested at 5 days after G. orontii infection and from uninfected control plants for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Salicylic acid (SA) is a critical molecule mediating plant innate immunity with an important role limiting the growth and reproduction of the virulent powdery mildew (PM) Golovinomyces orontii on Arabidopsis thaliana. To investigate this later phase of the PM interaction, and the role played by SA, we performed replicated global expression profiling for wild type and SA biosynthetic mutant ics1 Arabidopsis from 0 to 7 days post infection. We found that ICS1-impacted genes comprise 3.8% of profiled genes with known molecular markers of Arabidopsis defense ranked very highly by the multivariate empirical Bayes statistic (T2 statistic ((Tai and Speed, 2006)). Functional analyses of T2-selected genes identified statistically significant PM-impacted processes including photosynthesis, cell wall modification, and alkaloid metabolism that are ICS1-independent. ICS1-impacted processes include redox, vacuolar transport/secretion, and signaling. Our data also supports a role for ICS1 (SA) in iron and calcium homeostasis and identifies components of SA crosstalk with other phytohormones. Through our analysis, 39 novel PMâimpacted transcriptional regulators were identified. Insertion mutants in one of these regulators, PUX2, results in significantly reduced reproduction of the powdery mildew in a cell death independent manner. Though little is known about PUX2, PUX1 acts as a negative regulator of Arabidopsis CDC48 (Rancour et al., 2004; Park et al., 2007), an essential AAA-ATPase chaperone that mediates diverse cellular activities including homotypic fusion of ER and Golgi membranes, ER-associated protein degradation, cell cycle progression, and apoptosis. Future work will elucidate the functional role of the novel regulator PUX2 in PM resistance. Experiment Overall Design: Arabidopsis whole leaves were harvested at 6h, 1 day, 3 days, 5 days and 7 days after Golovinomyces orontii infection for RNA extraction and hybridization to Affymetrix Arabidopsis ATH1 microarrays. Gene expression profiles were obtained for wild type Columbia-0 and enhanced disease susceptibility mutant eds16-1, a null isochorismate synthase 1 (At1g74710) mutant. In parallel, uninfected samples were collected at 0 hr and 7days from wild type and mutant plants. The experiment includes 4 biological replicates.
Project description:ACTIN DEPOLYMERIZING FACTORs are involved in regulation of various aspects of plant physiologies, including plant immunity. However, it was not known how ADF regulates those plant physiologies. We hypothesized that ADFs regulate gene expression through regulation of nuclear organization. To test this hypothesis, we performed microarray analysis for A. thaliana adf mutants that were both uninfected and infected with powdery mildew.
Project description:Purpose: The powdery mildew fungus, Blumeria graminis, is an obligate biotrophic pathogen of cereals and has significant impact on food security (Dean et al., 2012). B. graminis f. sp. hordei (Bgh) is the causal agent of powdery mildew on barley (Hordeum vulgare L.). We sought to address the temporal regulation of membrane trafficking associated gene expression in barley-powdery mildew interactions. We created an isogenic panel of immune signaling mutants to address three main questions: (i) which Blumeria secreted proteins are differentially regulated in response to different compromised genotypes, (ii) which barley membrane trafficking genes are altered in response to pathogen attack, and (iii) how are these genes interacting across genotypes and infection stages.
Project description:For transcript analysis of early hypersensitive and susceptible responses of Medicago truncatula to the powdery mildew pathogen, Erysiphe pisi, we compared transcripts from pathogen-inoculated and control (non-inoculated) plants 12 h after infection in resistant (A14), partially resistant (A20), and susceptible (DZA315.16) genotypes. Published in: Medicago truncatula to the powdery mildew 1 and anthracnose pathogens, Erysiphe pisi and Colletotrichum trifolii. Molecular Plant Pathology 8(3):307-319 Keywords: 1 time points and 3 genotypes
Project description:Purpose: The powdery mildew fungus, Blumeria graminis, is an obligate biotrophic pathogen of cereals and has significant impact on food security (Dean et al., 2012. Molecular Plant Pathology 13 (4): 414-430. DOI: 10.1111/j.1364-3703.2011.00783.x). Blumeria graminis f. sp. hordei (Bgh) is the causal agent of powdery mildew on barley (Hordeum vulgare L.). We sought to identify small RNAs (sRNAs) from both barley and Bgh that regulate gene expression both within species and cross-kingdom.
Project description:To investigate the candidate genes governing Pm5.1 and their effects on powdery resistance, the RNA-sequencing based transcriptomes of the powdery mildew resistant segment substitution line SSL508-28 and recurrent parent D8 were compared 48 h after inoculation with the PM pathogen.