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: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:Purpose: The goal of this study is to identify small non-conding RNAs which are involved in rice resistance to Xoo. Methods: Rice leaves were inoculated with the Xoo strain PXO61 at the four-leaf to five-leaf stage by the leaf-clipping method. Control rice plants were inoculated with water (mock inoculation). And then, total RNA was extracted to be sequenced using Illumina GAIIx. Results: Using an optimized data analysis workflow to count the expression level of small ncRNA, we found several differentially expressed small ncRNA which may be participated in the interaction between rice and Xoo. Conclusions: Small ncRNA have be found to function in a variety of biological processes. Our study here has showed that several candidate miRNA or siRNA may play a significant role in rice immunity. Plants were inoculated with the Xoo strain PXO61 at the four-leaf to five-leaf stage by the leaf-clipping method. Control rice plants were inoculated with water (mock inoculation). Samples were collected before inoculation (ck) and at 2, 4, and 24 hours after PXO61 or mock inoculation from Rb49 and MDJ8. Leaf fragments approximately 2 cm in length that were immediately next to the inoculation site were collected.
Project description:Japonica rice (Oryza sativa ssp. japonica) variety Mudanjiang 8 (MDJ8) is the wild-type and is susceptible to Xoo. Transgenic rice line Rb49 carries the MR gene Xa3/Xa26, which is driven by its native promoter with the genetic background of MDJ8, and this line is resistant to certain strains (including strain PXO61) of Xoo. Although many studies on Xa3/Xa26-mediated resistace to rice Xoo have been published, the molecular mechanism of this major resistance gene remains poorly understood. Here, we use affymetrix microarray technology to analyze the regulated network mediated by Xa3/Xa26 We used microarrays to study the gene expression network mediated by Xa3/Xa26. Plants were inoculated with the Xoo strain PXO61 at the four-leaf to five-leaf stage by the leaf-clipping method. Control rice plants were inoculated with water (mock inoculation). Samples were collected before inoculation (ck) and at 2, 4, and 24 hours after PXO61 or mock inoculation from Rb49 and MDJ8. Leaf fragments approximately 2 cm in length that were immediately next to the inoculation site were collected.
Project description:Rice Xa21 resistance gene, which encodes a protein with predicted leucine-rich repeat (LRR), transmembrane, juxtamembrane, and intracellular kinase domains, conferred immunity to diverse strains of Xanthomonas oryzae pv. oryzae (Xoo). We generated Xa21 plant on TP309 background (Oryza Sativa Japonica). Systemic Acquired Resistance (SAR) in plants confers durable broad-spectrum resistance to pathogens and requires a phytohormone, salicylic acid (SA). Arabidopsis NPR1/NIM1 is a key regulator of the SAR response. Recently, we found that rice NPR1 homolog 1 (NH1) mediated enhanced resistance responses for Xoo (Chern et al., 2005b). We further investigated relating pathways in rice by identifying proteins that interact with NH1. One of them, constitutive over-expression of NH1 mediated negative regulator of resistance (NRR) gene caused enhanced susceptibility to Xoo , indicating that this gene product negatively affects to basal resistance response (Chern et al., 2005a). To dissect defense responses for rice bacterial blight pathogen, we planed microarray using two resistant mutant named with Xa21-TP309, NH1ox and one super-susceptible mutant (NRRox) before pathogen inoculation and one day post pathogen inoculation. Keywords: Biotic stress response Two or Three-condition experiment, NH1ox vs wild type control (LG) at two durations of Xoo inoculation (0d and 1d); NRRox vs wild type control (LG) at two durations of Xoo inoculation (0d and 1d); and Xa21vs wild type control (TP309) at three durations of Xoo inoculation (0d,1d and 2d);. Biological replicates: 2 or 4, independently grown and harvested.
Project description:Purpose: The goal of this study is to identify small non-conding RNAs which are involved in rice resistance to Xoo. Methods: Rice leaves were inoculated with the Xoo strain PXO61 at the four-leaf to five-leaf stage by the leaf-clipping method. Control rice plants were inoculated with water (mock inoculation). And then, total RNA was extracted to be sequenced using Illumina GAIIx. Results: Using an optimized data analysis workflow to count the expression level of small ncRNA, we found several differentially expressed small ncRNA which may be participated in the interaction between rice and Xoo. Conclusions: Small ncRNA have be found to function in a variety of biological processes. Our study here has showed that several candidate miRNA or siRNA may play a significant role in rice immunity.
Project description:Rice Xa21 resistance gene, which encodes a protein with predicted leucine-rich repeat (LRR), transmembrane, juxtamembrane, and intracellular kinase domains, conferred immunity to diverse strains of Xanthomonas oryzae pv. oryzae (Xoo). We generated Xa21 plant on TP309 background (Oryza Sativa Japonica). Systemic Acquired Resistance (SAR) in plants confers durable broad-spectrum resistance to pathogens and requires a phytohormone, salicylic acid (SA). Arabidopsis NPR1/NIM1 is a key regulator of the SAR response. Recently, we found that rice NPR1 homolog 1 (NH1) mediated enhanced resistance responses for Xoo (Chern et al., 2005b). We further investigated relating pathways in rice by identifying proteins that interact with NH1. One of them, constitutive over-expression of NH1 mediated negative regulator of resistance (NRR) gene caused enhanced susceptibility to Xoo , indicating that this gene product negatively affects to basal resistance response (Chern et al., 2005a). To dissect defense responses for rice bacterial blight pathogen, we planed microarray using two resistant mutant named with Xa21-TP309, NH1ox and one super-susceptible mutant (NRRox) before pathogen inoculation and one day post pathogen inoculation. Keywords: Biotic stress response
Project description:Vascular plant diseases, such as rice bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) and crucifer black rot caused by Xanthomonas campestris pv. campestris (Xcc), cause huge yield loss of crops worldwide. However, how plants operate vascular defense against these obligate pathogens remains elusive. In this study, we used both Arabidopsis and rice pathosystems to address the long-standing question. We found that the loss of function mutation of Arabidopsis mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP1) lost the non-host resistance to Xoo and supported Xoo to grow in the leaf veins, which also enhanced susceptibility to Xcc. MKP1 regulates the MPK3-mediated phosphorylation of the transcription factor MYB4 that functions in vascular lignification. Importantly, the MKP-MAPK cascade-mediated lignin biosynthesis is also conserved in rice through regulating OsMYB102 and OsMYB108, which control rice vascular resistance to adapted Xoo. Interestingly, the Arabidopsis and rice mutants enhanced resistance to the mesophyll cell pathogens most likely through upregulating salicylic acid biosynthesis, Pseudomonas syringae (P. syringae) and Xanthomonas oryzae pv. oryzicole (Xoc), respectively; strongly suggesting that this immune mechanism is likely specific to the obligate vascular pathogens. Therefore, our study uncovers a previously unrecognized vascular-specific and lignin-based immune mechanism, shedingshedding new sight on tissue-specific immunity in plants, as well as providing a practical approach for improvement of disease resistance against vascular pathogens in crops
Project description:To dissect the molecular mechanisms of resistance mediated by Xa39,the transcriptome profiling of a rice line carrying Xa39 and its parents at the early stage of Xoo infection were investigated. A rice introgression line H471 carrying Xa39 exhibited a typical local hypersensitive response phenotype, accompanied by programmed cell death after inoculation with the Xoo Philippines’ race 9b.Our results indicated there might be cross-talk between the Xa39-mediated signal transduction cascades and the GA/BR signaling pathway, and the defense mechanism was related to diverse kinases, transcription factors, post-translational regulation, and R genes.