Project description:Plant can perceive and respond natural sound vibration (SV). Artificial SV also served as a novel trigger of induced resistance, although approaches for activating such plant innate immunity intensively studied on the use of biological and chemical agents (BCA). Artificial SV pre-treatment protected Arabidopsis thaliana seedlings against insect pests and fungal pathogens. However, SV-mediated epigenetic modulation remains unexplored while CBA-mediated induced resistance is known as a complicated process involving epigenetic regulation. Here, we performed a ChIP-seq analysis to understand the role of 10 kHz SV-mediated epigenetic modification in induced resistance against a soil-borne pathogenic bacterium Ralstonia solanacearum.
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. Experiment Overall Design: wild type Col-0 and chitin receptor mutants treated with or without chitooctaose
Project description:Plant can perceive and respond natural sound vibration (SV). Artificial SV also served as a novel trigger of induced resistance, although approaches for activating such plant innate immunity intensively studied on the use of biological and chemical agents (BCA). Artificial SV pre-treatment protected Arabidopsis thaliana seedlings against insect pests and fungal pathogens. However, SV-mediated epigenetic modulation remains unexplored while CBA-mediated induced resistance is known as a complicated process involving epigenetic regulation. Here, we performed an expression profiling basd on small RNA-seq experiment to understand the role of 10 kHz SV-mediated epigenetic modification in induced resistance against a soil-borne pathogenic bacterium Ralstonia solanacearum.
Project description:Plant can perceive and respond natural sound vibration (SV). Artificial SV also served as a novel trigger of induced resistance, although approaches for activating such plant innate immunity intensively studied on the use of biological and chemical agents (BCA). Artificial SV pre-treatment protected Arabidopsis thaliana seedlings against insect pests and fungal pathogens. However, SV-mediated epigenetic modulation remains unexplored while CBA-mediated induced resistance is known as a complicated process involving epigenetic regulation. Here, we performed a gene expression profiling basd on RNA-seq experiment to understand the role of 10 kHz SV-mediated epigenetic modification in induced resistance against a soil-borne pathogenic bacterium Ralstonia solanacearum.
Project description:Plants establish mutualistic association with beneficial microbes while deploy the immune system to defend against pathogens. Little is known about the interplay between mutualism and immunity and about the mediator molecules. Here we show that plants respond differently to a bacterial volatile compound through integral modulation of the immune system and the phosphate starvation response (PSR) system, resulting in either mutualism or immunity. We found that the same exposure of a recognized plant growth-promoting rhizobacterium unexpectedly causes either beneficial or deleterious effects to plants. The beneficial-to-deleterious transition is dependent on plant nutrition of phosphorus (P) and is mediated by diacetyl (DA), a bacterial volatile compound. In P-sufficient plants, DA partially suppresses plant production of reactive oxygen species (ROS) and enhances symbiont colonization without compromising disease resistance. In P-deficient plants, DA elevates phytohormone-mediated immunity and consequently causes plant hypersensitivity to P deficiency. Therefore, DA affects the types of relation between plants and certain rhizobacteria in a way that depends on plant PSR system and phytohormone-mediated immunity.
Project description:Development of cereal crops with high nitrogen-use efficiency (NUE) is a priority for worldwide agriculture. In addition to conventional plant breeding and genetic engineering, the use of the plant microbiome offers another approach to improve crop NUE. To gain insight into the bacterial communities associated with sorghum lines that differ in NUE, a field experiment was designed comparing 24 diverse sorghum lines under sufficient and deficient nitrogen (N). Amplicon sequencing and untargeted gas chromatography-mass spectrometry (GC-MS) were used to characterize the bacterial communities and the root metabolome associated with sorghum genotypes varying in sensitivity to low N. We demonstrated that N stress and sorghum type (energy, sweet, and grain sorghum) significantly impacted the root-associated bacterial communities and root metabolite composition of sorghum. We found a positive correlation between sorghum NUE and bacterial richness and diversity in the rhizosphere. The greater alpha diversity in high NUE lines was associated with the decreased abundance of a dominant bacterial taxa, Pseudomonas. Multiple strong correlations were detected between root metabolites and rhizosphere bacterial communities in response to low-N stress. This indicates that the shift in the sorghum microbiome due to low-N is associated with the root metabolites of the host plant. Taken together, our findings suggest that host genetic regulation of root metabolites plays a role in defining the root-associated microbiome of sorghum genotypes differing in NUE and tolerance to low-N stress.
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:The zig-zag model of host-pathogen interaction describes the relative strength of defense response across a spectrum of pathogen-induced plant phenotypes. A stronger defense response results in increased resistance. Here, we investigate the strength of pathogen virulence during disease and place these findings in the context of the zig-zag model. Xanthomonas vasicola pv. holcicola (Xvh) causes sorghum bacterial leaf streak. Despite being widespread, this disease has not been described in detail at the molecular level. We divided diverse sorghum genotypes into three groups based on disease symptoms: water-soaked lesions, red lesions, and resistance. Bacterial growth assays confirmed that these three phenotypes represent a range of resistance and susceptibility. To simultaneously reveal defense and virulence responses across the spectrum of disease phenotypes, we performed dual RNA-seq on Xvh-infected sorghum. Consistent with the zig-zag model, the expression of plant defense-related genes was strongest in the resistance interaction. Surprisingly, bacterial virulence genes related to the type III secretion system (T3SS) and type III effectors (T3Es) were also most highly expressed in the resistance interaction. This expression pattern was observed at multiple time points within the sorghum-Xvh pathosystem. Further, a similar expression pattern was observed in Arabidopsis infected with Pseudomonas syringae for effector-triggered immunity via AvrRps4 but not AvrRpt2. Specific metabolites were able to repress the Xvh virulence response in vitro and in planta suggesting a possible signaling mechanism. Taken together, these findings reveal multiple permutations of the continually evolving host-pathogen arms race from the perspective of host defense and pathogen virulence responses.
Project description:The cell wall is among the first plant structures encountered by necrotrophic fungal pathogens, such as Botrytis cinerea. The composition of plant cell walls varies depending on the species, type of cell or tissue, and stage of development. Cell walls are important reservoirs of energy-rich sugars for pathogens, but also are barriers that impair colonization of host tissues. Growing fungal hyphae secrete enzymes that hydrolyze cell wall polysaccharides. Degradation of wall polysaccharides provides nutrients for the pathogen and improves the access of secreted Botrytis enzymes to all host cell wall targets and cytoplasmic constituents. Destruction of host cell walls results in tissue maceration, a hallmark of diseases caused by Botrytis. The Botrytis genome encodes 1,155 predicted carbohydrate-active enzyme (CAZy) genes; products of 275 are potentially secreted. Transcriptome sequencing identified Botrytis CAZy genes expressed during infections of lettuce leaves, ripe tomato fruit and grape berries. On all three hosts, Botrytis expresses a common group of 229 predicted CAZy genes including 28 pectin-modifying enzymes, 21 hemicellulose-modifying proteins, 18 enzymes targeting pectin and hemicellulose side-branches, and 16 enzymes that may degrade cellulose. Pectin polysaccharides are abundant in grape and tomato cell walls, but lettuce leaf walls are predominantly hemicelluloses and cellulose. These results suggest that Botrytis targets similar wall polysaccharide networks; e.g., pectins, on leaves and fruit, but also attacks unique host wall polysaccharide substrates The diversity of the Botrytis CAZy proteins may be partly responsible for its wide host range. 3 biological replicates consisting of groups of infected tomato fruits from different plants