Transcriptional profiling of Cellulase induced hypersensitive reaction like response in rice
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ABSTRACT: Cellulase, a Type II secretion system secreted protein of Xanthomonas oryzae pv. oryzae (Xoo; the casual of bacterial leaf blight of rice) is a potent inducer of rice defense responses such as hypersensitive response like reactions (HR), callose depositions, cell death associated with nuclear fragmentations and impart functional resistance against further Xoo inoculation In order to understand the molecular events associated with cellulase induced HR in rice, whole genome transcriptional profiling was performed using Affymetrix Rice GeneChips Keywords: Expression profiling of a hypersensitive reaction like response Leaves of 20 days old green house grown susceptible rice cultivar (Taichung Native-1; TN-1) were infiltrated with either 30-40μl of purified Xoo cellulase (5μg/ml) or with buffer (10mM potassium phosphate buffer pH 6.0) alone (as described in Jha et al. 2007; MPMI vol 20, pp 31-40). The plants were shifted to a growth chamber (28oC; 80% relative humidity; 12/12h light/dark cycle) 48 hours before the treatment. 20-30 leaf pieces covering the infiltrated zone from each of the treatments were harvested 12 h after infiltration. Total RNA isolated from the pooled samples was subjected for expression analysis using Affymetrix GeneChip System. The experiment was repeated with three different biological replicates using RNA isolated from three batches of rice leaves treated with the freshly purified Xoo cellulase and the buffer
Project description:Treatment of rice tissues with purified preparations of a Xanthomonas oryzae pv. oryzae (Xoo) secreted plant cell wall degrading enzyme, Lipase/Esterase (LipA), elicits cell wall damage induced innate immune responses. LipA activity is required for induction of defense responses. In order to characterize the early events during elaboration of cell wall degrading enzyme, Lipase/Esterase (LipA) induced innate immune response in rice, we have performed global gene expression profiling of rice leaves treated with purified LipA at early time points, 30 minutes and 120min, after treatment. Whole genome transcriptional profiling was performed using Affymetrix Rice GeneChips Leaves of two weeks old green house grown susceptible rice cultivar (Taichung Native-1; TN-1) were infiltrated with either 30-40μl of purified Xoo Lipase/Esterase (LipA)(500μg/ml) or with buffer (10mM potassium phosphate buffer pH 6.0) alone (as described in Jha et al. 2007; MPMI vol 20, pp 31-40). The plants were shifted to a growth chamber (28oC; 80% relative humidity; 12/12h light/dark cycle) 48 hours before the treatment. 20-30 leaf pieces covering the infiltrated zone from each of the treatments were harvested 30 min. and 120 min. after infiltration. Total RNA isolated from the pooled samples was subjected for expression analysis using Affymetrix GeneChip System. The experiment was repeated with three different biological replicates using RNA isolated from three batches of rice leaves treated with the freshly purified Xoo Lipase/Esterase (LipA)and the buffer Gene Expression profiling of rice leaves undergoing an innate immune respone induced by LipA (Lipase/Esterase A) enzyme
Project description:Cellulase, a Type II secretion system secreted protein of Xanthomonas oryzae pv. oryzae (Xoo; the casual of bacterial leaf blight of rice) is a potent inducer of rice defense responses such as hypersensitive response like reactions (HR), callose depositions, cell death associated with nuclear fragmentations and impart functional resistance against further Xoo inoculation In order to understand the molecular events associated with cellulase induced HR in rice, whole genome transcriptional profiling was performed using Affymetrix Rice GeneChips Keywords: Expression profiling of a hypersensitive reaction like response
Project description:Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial blight disease, is one of the major threats to rice productivity. Yet, the molecular mechanism of rice-Xoo interaction is elusive. Here, we report comparative proteome profiles of Xoo susceptible (Dongjin) and resistant (Hwayeong) cultivars of rice in response to two-time points (3 and 6 days) of Xoo infection. Low-abundance proteins were enriched using a protamine sulfate (PS) precipitation method and isolated proteins were quantified by a label-free quantitative analysis, leading to the identification of 3846 protein groups. Of these, 1128 proteins were significantly changed between mock and Xoo infected plants of Dongjin and Hwayeong cultivars. Based on the abundance pattern and functions of the identified proteins, a total of 23 candidate proteins were shortlisted that potentially participate in plant defense against Xoo in the resistant cultivar. Of these candidate proteins, a mitochondrial arginase-1 showed Hwayeong specific abundance and was significantly accumulated following Xoo inoculation. Overexpression of arginase-1 in susceptible rice cultivar (Dongjin) resulted in enhanced tolerance against Xoo as compared to the wild-type (WT). In addition, expression analysis of defense-related genes encoding PR1, glucanase I, and chitinase II by qRT-PCR showed their enhanced expression in the overexpression lines as compared to WT. Mitochondrial localization of the selected arginase was further confirmed by fluorescent microscopy using GFP-tagged arginase. Taken together, our results uncover the proteome changes in the rice cultivars and highlight the functions of arginase in plant defense against Xoo.
Project description:Xanthomonas oryzae pv. oryzae (Xoo) is a rice pathogen causing bacterial blight, which outbreaks in most rice cultivating countries and reduces yield up to 50% due to no effective pesticide. Urgent responses of Xoo upon the initial contacts with rice at infection site are essential for pathogenesis. We studied the time-resolved gene expression of both transcriptome and proteome in the pathogenicity-activated Xoo cells with an in vitro assay system. Genes related to cell mobility, inorganic ion transport and effectors are early response genes to help Xoo cells invade into damaged rice leaf tissues, obtain rare cofactors, and evade rice immune responses. Although the time-resolved gene expression pattern of Xoo is conserved in both mRNA and protein, there are varied time gaps in genes between the expression peaks of mRNA and protein, which implies there is an additional translational selection step of specific mRNAs for rapid translation. The expression pattern of genes from a polycistronic mRNA in the same gene cluster is strictly conserved. The time-resolved gene expression study of Xoo in both transcriptome and proteome provides a valuable information about the pathogenic responses of Xoo at the initial stage of Xoo-rice interaction.
Project description:The plant cell wall degrading enzyme LipA (Lipase/Esterase A) is a Type II secretion system secreted protein of Xanthomonas oryzae pv. oryzae (Xoo; the casual of bacterial leaf blight of rice). LipA is an Xoo virulence factor. However, LipA is a double edged sword for Xoo as it induces rice defense responses such as programmed cell death/hypersensitive response like reaction (HR) and callose deposition. Prior treatment with LipA enhances resistance against subseqent Xoo infection. In order to understand the molecular events associated with Esterase (LipA) induced innate immune responsein rice , whole genome transcriptional profiling was performed using Affymetrix Rice GeneChips
Project description:affy_xoo_rice - affy_xoo_rice - The Bacterial Leaf Blight disease of rice is due to Xanthomonas oryzae pv. oryzae. As for many pathogenic bacteria, it relies on a type 3 secretion system that is devoted to the injection of type 3 effectors into the eukaryotic host cell. These proteins are meant to suppress host basal defense responses and/or mimic some host regulatory function promoting bacterial survey in the plant. We are interested in the functional analysis of a subgroup of Xoo T3Es, that are specialized in host cell transcriptome remodelling. These effectors, therefore called TAL for Transcription Activator-Like proteins (also named AvrBs3/PthA-like), are often key virulence factors essential to Xoo pathogenicity such as the effector protein Talc of african Xoo strain BAI3. Our goal is to understand its function during disease development, by identifying rice host genes that are being directly up- or down-regulated by Talc. To that end, we aim at performing Affymetrix transcriptomic analysis, comparing leaf samples of a susceptible rice line inoculated with Xoo to leaves challenged with a Talc-deficient mutant and water-treated leaves. Highly induced genes are likely to be Talc primary targets and therefore potentially good susceptibility gene candidates.-The goal of the experiment is to identify the rice genes up- or down-regulated by the type III effector Talc from Xoo African strain BAI3, upon the inoculation of susceptible rice leaves 24 hours post-infection. To that end, the experimental design includes the inoculation of Nipponbare rice leaves with the virulent Xoo strain BAI3, that will be compared to Nipponbare rice leaves inoculated with a talc K.O. mutant strain and water. Keywords: wt vs virulence mutant 9 arrays - rice
Project description:Lipopolysaccharide is a Microbe Associated Molecular Pattern (MAMP) that is known to induce defense responses in plants. We have shown that treatment of rice leaves with Xoo LPS induces callose deposition, reactive oxygen production and enhances resistance against subsequent infection by the pathogen. We have performed transcriptional profiling of rice leaves that are treated with Xoo LPS to identify differentially expressed genes. Xoo LPS was injected into mid-veins of rice leaves and RNA was isolated 15 hours later.
Project description:The transcriptomic modulations leading to defense response in rice one hour after inoculation by Xanthomonas oryzae pv oryzae. Xoo and mock inoculated plant of cultivars IET8585 (bacterial leaf blight resistant) and IR-24 (bacterial leaf blight susceptible) were compared.
Project description:Previously, we successfully introduce the bacterial blight resistance trait from Oryza meyeriana into O. sativa using asymmetric somatic hybridization with O. meyeriana as the donor species. After years of breeding, a progeny named Y73 was generated with recurrent parent O. sativa L. ssp. japonica cv. Dalixiang, and it shows high resistance to broad-spectrum of bacterial blight pathogens Xanthomonas oryzae pv. Oryzae (Xoo). However, the resistance mechanism of Y73 is remain undiscovered. To provide insights into the high resistance phenotype of these plants, we examined the transcriptome response in leaves of Y73 to the bacterial blight infection in this study. Xoo inoculated and mock inoculated rice plants were grown in growth room and the global analysis of gene expression events in rice leaves at 24 hours post inoculation (hpi) were analyzed using Affymetrix Rice GeneChip microarrays. We used microarrays to detail the global programme of gene expression underlying Xoo infection in rice Y73. To find out pathways and genes involved in its high and board-spectrum resistance, microanalysis were carried out on Y73 after Xoo infection at 24 hours post inoculation (hpi). Three independant replicates were perfomed for each treatments.
Project description:Endogenous small RNAs are newly identified players in plant immune responses, yet their roles in rice (Oryza sativa) responding to pathogens are still less understood, especially for pathogens that can cause severe yield losses. Here, we examined the small RNA expression profiles of rice leaves at 2, 6, 12, and 24 hours post infection of Xanthomonas oryzae pv. oryzae (Xoo) virulent strain PXO99, the causal agent of rice bacterial blight disease. Dynamic expression changes of some miRNAs and trans-acting siRNAs (ta-siRNAs) were identified, together with a few novel miRNA targets, including a disease resistance gene targeted by osa-miR159a.1. Coordinated expression changes were observed among some miRNA and ta-siRNAs in response to Xoo infection, with small RNAs exhibiting the same expression pattern tended to regulate genes in the same or functional correlated signaling pathways, including auxin and GA signaling pathways, nutrition and defense related pathways, etc. Highly abundant small RNAs with pathogen-responsive expression changes were identified from the exonic region of a protein-coding gene, which may present a new class of functional small RNAs. These findings reveal the dynamic and complex roles of small RNAs in rice-pathogen interactions, and identified new targets for regulating plant immune responses. Examination of the small RNA expression profiles of rice leaves at 2, 6, 12, and 24 hours post infection of Xanthomonas oryzae pv. oryzae (Xoo) virulent strain PXO99