Project description:Heterologous expression of the fungal pathogen Cladosporium fulvum Avr2 in Arabidopsis plants. Experiment Overall Design: Samples used for microarray analyses were replicated three times in independent experiments and each replication consisted of 10 Avr2-expressing Arabidopsis plants and 10 Col-0 plants grown for four weeks under standard greenhouse conditions
Project description:The fungal pathogen Ustilago maydis establishes a biotrophic relationship with its host plant maize. Hallmarks of the disease are large plant tumors in which fungal proliferation occurs. Plants have developed various defense pathways to cope with pathogens. We used microarrays to detail the global programme of gene expression during the infection process of Ustilago maydis in its host plant to get insights into the defense programs and the metabolic reprogramming needed to supply the fungus with nutrients. Keywords: time course
Project description:In response to biotic stress, plants produce suites of highly modified fatty acids that bear unusual chemical functionality. Despite their chemical complexity and proposed roles in pathogen defense, little is known about the biosynthesis of these decorated fatty acids in plants. Falcarindiol is a prototypical acetylenic lipid present in carrot, tomato, and celery that inhibits growth of fungi and human cancer cell lines. Using a combination of untargeted metabolomics and RNA sequencing, we discovered a biosynthetic gene cluster in tomato (Solanum lycopersicum) that is required for the production of falcarindiol in response to an adapted fungal pathogen, Cladosporium fulvum. By reconstituting the initial biosynthetic steps in a heterologous host (Nicotiana benthamiana) and generating transgenic pathway mutants in tomato, we demonstrate a direct role for three genes in the cluster in falcarindiol biosynthesis. This work reveals a mechanism by which plants sculpt their lipid pool in response to pathogens, and provides critical insight into the complex biochemistry of alkynyl lipid production.
Project description:Verticillium longisporum is a soil-borne fungal pathogen causing vascular disease predominantly in oilseed rape. The pathogen enters its host through the roots and entertains a parasitic life stage in the xylem before invading other tissues late in the infection cycle. We have started to approach the question how and when the host plant senses the colonization of the xylem using Arabidopsis thaliana as a model plant. Although the stress-related phytohormones salicylic acid, jasmonic acid and abscisic acid increase only at 28 to 35 days, expression of V. longisporum-induced genes (VliGs) starts in the leaf veins as early as 5 dpi when disease symptoms and fungal DNA cannot yet be detected. It is concluded that an elicitor is transported from the root to the aerial parts. More than one third of the VliGs identified by whole genome expression profiling at 18 dpi encode apoplastically localized proteins involved in cell wall modifications and potential defense responses. The identified VliGs provide a useful tool to elucidate the contribution of the induced genes to the disease phenotype and the defense response. Moreover, they will help to identify the elicitor(s) and the components of the signal transduction chain that shape the V. longisporum – plant interaction. Keywords: Arabidopsis, cell wall, microarray, phytohormones, Verticillium longisporum, xylem
Project description:Fungal effectors play important roles in inciting disease development on host plants. We identified an effector (Secreted in Xylem4, SIX4) in an Arabidopsis infecting isolate (Fo5176) of the root-infecting fungal pathogen Fusarium oxysporum and demonstrated this effector is required for full virulence. To explore the role of Fo5176_SIX4 we use whole transcriptome profiling of root tissues from plants overexpressing this effector (35sSIX4) versus wild-type (Col-0) plants after F. oxysporum infection. Published in DOI:10.1007/978-3-319-42319-7_4. Belowground Defence Strategies in Plants.
Project description:A LysM Receptor-like Kinase Mediates Chitin Perception and Fungal Resistance in Arabidopsis Jinrong Wan,1 Xuecheng Zhang,1 David Neece,2 Katrina M. Ramonell,3 Steve Clough,2,4 Sung-yong Kim,1 Minviluz Stacey,1 and Gary Stacey1* 1Division of Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center, University of Missouri-Columbia, Columbia, MO 65211, USA 2Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA 3Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA 4US Department of Agriculture, Soybean/Maize Germplasm, Pathology and Genetics Research, Urbana, IL 61801, USA *To whom correspondence should be addressed. E-mail: staceyg@missouri.edu Abstract: Chitin, a polymer of N-acetyl-D-glucosamine, is found in fungal cell walls, but not in plants. Plant cells are capable of perceiving chitin fragments (chitooligosaccharides) to trigger various defense responses. We identified a LysM receptor-like protein (AtLysM RLK1) that is required for the perception of chitooligosaccharides in Arabidopsis. Mutation of this gene blocked the induction of almost all chitooligosaccharide-responsive genes (CRGs) and led to more susceptibility to fungal pathogens, but not to a bacterial pathogen. In addition, exogenously applied chitooligosaccharides enhanced resistance against both fungal and bacterial pathogens in the wild-type plants, but not in the mutant. Together, our data strongly suggest AtLysM RLK1 is the chitin receptor or a key part of the receptor complex and chitin is a PAMP (pathogen-associated molecular pattern) in fungi recognized by the receptor leading to the induction of plant innate immunity against fungal pathogens. Since LysM RLKs were also recently shown to be critical for the perception of the rhizobial lipo-chitin Nod signals, our data suggest that LysM RLKs not just recognize friendly symbiotic rhizobia (via their lipo-chitin Nod signals), but also hostile fungal pathogens (via their cell wall chitin). These data suggest a possible evolutionary relationship between the perception mechanisms of Nod signals and chitin by plants. Keywords: chitooctaose, chitin receptor mutant
Project description:Comparative transcriptomic analysis of Arabidopsis thaliana yda11 plants (in Col-0 background), and wild-type plants (Col-0) non-infected or infected with the necrotrophic fungal pathogen Plectosphaerella cucumerina BMM (PcBMM)
Project description:The fungal pathogen Fusarium moniliforme causes ear rot in maize. Ear rot in maize is a destructive disease globally caused by Fusarium moniliforme , due to decrease of grain yield and increase of risks in raising livestock by mycotoxins production. Plants have developed various defense pathways to cope with pathogens. We used microarrays to detail the global programme of gene expression during the infection process of Fusarium moniliforme in its host plant to get insights into the defense programs and the host processes potentially involved in plant defense against this pathogen.
Project description:The fungal pathogen Ustilago maydis establishes a biotrophic relationship with its host plant maize. Hallmarks of the disease are large plant tumors in which fungal proliferation occurs. Plants have developed various defense pathways to cope with pathogens. We used microarrays to detail the global programme of gene expression during the infection process of Ustilago maydis in its host plant to get insights into the defense programs and the metabolic reprogramming needed to supply the fungus with nutrients. Experiment Overall Design: In three independent experiments plants were infected with the solopathogenic U. maydis strain SG200. Samples from infected leaves were taken at 12 and 24 hours post infection, as well as 2, 4 and 8 days post infection. Samples from uninfected control plants were taken at the same time points.
Project description:Chitin oligomers, released from fungal cell walls by endochitinase, induce defense and related cellular responses in many plants. However, little is known about chitin responses in the model plant Arabidopsis. We describe here a large scale characterization of gene expression patterns in Arabidopsis in response to chitin treatment using an Arabidopsis microarray consisting of 2,375 EST clones representing putative defense-related and regulatory genes. Transcript levels for 71 ESTs, representing 61 genes, were altered >3-fold in chitin-treated seedlings relative to control seedlings. A number of transcripts exhibited altered accumulation as early as 10 min after exposure to chitin, representing some of the earliest changes in gene expression observed in chitin-treated plants. Included among the 61 genes are those that have been reported to be elicited by various pathogen-related stimuli in other plants. Additional genes, including genes of unknown function, were also identified broadening our understanding of chitin-elicited responses. Among transcripts with enhanced accumulation, one cluster was enriched in genes with both the W-box promoter element and a novel regulatory element. In addition, a number of transcripts had decreased abundance, encoding several proteins involved in cell wall strengthening and wall deposition. The chalcone synthase promoter element was identified in the upstream regions of these genes, suggesting that pathogen signals may suppress expression of some genes. These data indicate that Arabidopsis will be an excellent model to elucidate mechanisms of chitin elicitation in plant defense. Groups of assays that are related as part of a time series. Keywords: time_series_design