Project description:Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc) are important bacterial pathogens of the worldwide staple and grass model, rice. Xoo invades rice vascular tissue to cause bacterial leaf blight, a serious disease of rice throughout the world. Xoc colonizes the parenchyma tissue to cause bacterial leaf steak, a disease of emerging importance. We have designed oligonucleotide probes (50-70-mers) represented 2,858 Xoo genes and 1,816 Xoc genes annotated by The Institute for Genomic Research (TIGR). To validate the Xo arrays, self-hybridization samples and tests of the non-specific hybridization using randomly spotted oligonucleotides corresponding to the hygromycin phosphotransferase gene (hph), and blank spot and of the correlation coefficient between biological replicates as well as between duplicate spots revealed that the data generated from our oligo array were highly reliable and consistent. To demonstrate application of Xo array, we performed expression profiling experiments on arrays hybridized with RNA of Xoo and Xoc grown in the two different nutrient-condition media. Several sets of genes involved in bacterial movement, chemotaxis, and hrp genes differentially express in response to different treatment. Due to comprehensive views of microarray study, extended biological events of plant-bacteria interaction was described. This publicly available microarray for Xanthomonas oryzae (Xo) is an enabling resource for a large and international community of scientists to better understand not only Xo biology but also many other Xanthomonas species that cause significant losses on crops. Keywords: Media condition response
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.
Project description:Xanthomonas oryzae pv. oryzae (Xoo) causes the bacterial leaf blight of rice, which leads to as much as 50% yield losses. To understand the landscape of virulence mechanisms, we constructed in planta transcriptional profiling of Xoo KACC10331 using RNA-seq. Three in planta transcriptome of Xoo KACC10331 derived from infected rice leafs were compared to three in vitro data from rich media. To obtain differentially expressed genes, we used the DEGseq package with MA-plot-based method in the R statistical environment and identified 2,094 transcripts that were significantly altered.
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:African Xanthomonas oryzae pv. oryzae strains seem most closely related to and share several genetic features with pathovar oryzicola despite causing symptoms of bacterial leaf blight. The ability of most Xanthomonas plant pathogenic bacteria to infect their host relies on the action of a specific family of type III effectors called the TAL effectors. These microbial transcription factors are injected into the plant and manipulate the host transcriptome upon binding to the promoters of plant genes. The genes whose induction is of benefit to the pathogen are called susceptibility genes. RNA profiling experiments in rice using the Malian Xoo strain MAI1 and in silico prediction of TAL effector binding sites were carried out to identify candidate targets of TalB, revealing OsTFX1, a bZIP transcription factor previously identified as a bacterial blight S gene, and OsERF#123, which encodes a subgroup IXc AP2/ERF transcription factor.
Project description:Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc) are important bacterial pathogens of the worldwide staple and grass model, rice. Xoo invades rice vascular tissue to cause bacterial leaf blight, a serious disease of rice throughout the world. Xoc colonizes the parenchyma tissue to cause bacterial leaf steak, a disease of emerging importance. We have designed oligonucleotide probes (50-70-mers) represented 2,858 Xoo genes and 1,816 Xoc genes annotated by The Institute for Genomic Research (TIGR). To validate the Xo arrays, self-hybridization samples and tests of the non-specific hybridization using randomly spotted oligonucleotides corresponding to the hygromycin phosphotransferase gene (hph), and blank spot and of the correlation coefficient between biological replicates as well as between duplicate spots revealed that the data generated from our oligo array were highly reliable and consistent. To optimize the suitable protocol for hybridizing sample onto XOarray slides, we performed hybridization with 4 temperature levels (42 0C, 44 0C, 48 0C, and 52 0C) and 5 numbers of template amounts (10 pMol, 20 pMol, 30 pMol, 40 pMol, and 50 pMol) for hybridization process. Two level of PMT (Power of the scanner photomultiplicator) exposed to hybridized glass slides. Total samples is 36 slides (4 temperatures x 2 technical replicates x 2 PMT level = 16 slides and 5 numbers of template amount x 2 technical replicates x 2 PMT level = 20 slides). Keywords: Condition Optimization
Project description:In bacteria, two-component regulatory system (TCSs) is generally characterized by a simple phosphotransfer scheme, composed of a sensor domain (a histidine kinase) and a response domain (a response regulator), which is responsible for detection of external stimuli. PhoP-PhoQ TCS of Xanthomonas oryzae pv. oryzae (Xoo), a causal agent of bacterial leaf blight disease in rice, was previously shown to be negatively regulated by RaxR-RaxH, another TCS that senses population cell density as well as modulates the activity of AvrXA21, a bacterial effector, recognized by a bacterial blight resistance gene, Xa21. In this work, whole-genome microarray was performed to analyze transcription profiling and identify member of PhoP regulon under Mg2+ and Ca2+ limited condition. This analysis revealed that PhoP governs broad cellular pathways including stress defense response, cation transportation, general metabolism, broad regulatory system, bacterial motility, and bacterial virulence. Array results provide a set of candidate genes, further biochemical pathway analysis, and signaling pathway crosstalks that need to be characterized to understand PhoP-dependent mechanisms and also suggest a putative regulatory loop between two phoP-phoQ and raxR-raxH TCSs. Implication of this analysis suggested that Xoo adopt PhoP-PhoQ system to perceive extracellular signals from certain environment such as low concentration of metal ions, and to regulate intracellular signals of other regulatory systems. Keywords: Comparative transcription profiling under limited Mg2+ Ca2+ condition
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.
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