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Min-Young Song,
Chi-Yeol Kim,
Muho Han,
Hak-Seung Ryu,
Sang-Kyu Lee,
Li Sun,
Zuhua He, Young-Su Seo,
Patrick Canal,
Pamela C Ronald,
Jong-Seong Jeon
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ABSTRACT: The required for Mla12 resistance (RAR1) protein is essential for the plant immune response. In rice, a model monocot species, the function of Oryza sativa RAR1 (OsRAR1) has been little explored. In our current study, we characterized the response of a rice osrar1 T-DNA insertion mutant to infection by Magnaporthe oryzae, the causal agent of rice blast disease. osrar1 mutants displayed reduced resistance compared with wild type rice when inoculated with the normally virulent M. oryzae isolate PO6-6, indicating that OsRAR1 is required for an immune response to this pathogen. We also investigated the function of OsRAR1 in the resistance mechanism mediated by the immune receptor genes Pib and Pi5 that encode nucleotide binding-leucine rich repeat (NB-LRR) proteins. We inoculated progeny from Pib/osrar1 and Pi5/osrar1 heterozygous plants with the avirulent M. oryzae isolates, race 007 and PO6-6, respectively. We found that only Pib-mediated resistance was compromised by the osrar1 mutation and that the introduction of the OsRAR1 cDNA into Pib/osrar1 rescued Pib-mediated resistance. These results indicate that OsRAR1 is required for Pib-mediated resistance but not Pi5-mediated resistance to M. oryzae.
Molecules and Cells 04/2013; · 2.18 Impact Factor
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Eunhye Goo,
Charlotte D Majerczyk,
Jae Hyung An,
Josephine R Chandler, Young-Su Seo,
Hyeonheui Ham,
Jae Yun Lim,
Hongsup Kim,
Bongsoo Lee,
Moon Sun Jang,
E Peter Greenberg,
Ingyu Hwang
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ABSTRACT: Acyl-homoserine lactone-mediated quorum sensing (QS) regulates diverse activities in many species of Proteobacteria. QS-controlled genes commonly code for production of secreted or excreted public goods. The acyl-homoserine lactones are synthesized by members of the LuxI signal synthase family and are detected by cognate members of the LuxR family of transcriptional regulators. QS affords a means of population density-dependent gene regulation. Control of public goods via QS provides a fitness benefit. Another potential role for QS is to anticipate overcrowding. As population density increases and stationary phase approaches, QS might induce functions important for existence in stationary phase. Here we provide evidence that in three related species of the genus Burkholderia QS allows individuals to anticipate and survive stationary-phase stress. Survival requires QS-dependent activation of cellular enzymes required for production of excreted oxalate, which serves to counteract ammonia-mediated alkaline toxicity during stationary phase. Our findings provide an example of QS serving as a means to anticipate stationary phase or life at the carrying capacity of a population by activating the expression of cytoplasmic enzymes, altering cellular metabolism, and producing a shared resource or public good, oxalate.
Proceedings of the National Academy of Sciences 11/2012; · 9.68 Impact Factor
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ABSTRACT: Pantoea ananatis is the causative agent of sheath and grain rot in rice. Here, we present the complete genome sequence of P. ananatis strain PA13, originally isolated from a diseased rice grain.
Journal of bacteriology 01/2012; 194(2):531. · 3.94 Impact Factor
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ABSTRACT: Rice is a staple food for one-half the world's population and a model for other monocotyledonous species. Thus, efficient approaches for identifying key genes controlling simple or complex traits in rice have important biological, agricultural, and economic consequences. Here, we report on the construction of RiceNet, an experimentally tested genome-scale gene network for a monocotyledonous species. Many different datasets, derived from five different organisms including plants, animals, yeast, and humans, were evaluated, and 24 of the most useful were integrated into a statistical framework that allowed for the prediction of functional linkages between pairs of genes. Genes could be linked to traits by using guilt-by-association, predicting gene attributes on the basis of network neighbors. We applied RiceNet to an important agronomic trait, the biotic stress response. Using network guilt-by-association followed by focused protein-protein interaction assays, we identified and validated, in planta, two positive regulators, LOC_Os01g70580 (now Regulator of XA21; ROX1) and LOC_Os02g21510 (ROX2), and one negative regulator, LOC_Os06g12530 (ROX3). These proteins control resistance mediated by rice XA21, a pattern recognition receptor. We also showed that RiceNet can accurately predict gene function in another major monocotyledonous crop species, maize. RiceNet thus enables the identification of genes regulating important crop traits, facilitating engineering of pathways critical to crop productivity.
Proceedings of the National Academy of Sciences 11/2011; 108(45):18548-53. · 9.68 Impact Factor
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Hokyoung Son, Young-Su Seo,
Kyunghun Min,
Ae Ran Park,
Jungkwan Lee,
Jian-Ming Jin,
Yang Lin,
Peijian Cao,
Sae-Yeon Hong,
Eun-Kyung Kim, [......],
Yongsoo Kim,
Jung-Eun Kim,
Jin-Cheol Kim,
Gyung Ja Choi,
Sung-Hwan Yun,
Jae Yun Lim,
Minkyun Kim,
Yong-Hwan Lee,
Yang-Do Choi,
Yin-Won Lee
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ABSTRACT: Fusarium graminearum is an important plant pathogen that causes head blight of major cereal crops. The fungus produces mycotoxins that are harmful to animal and human. In this study, a systematic analysis of 17 phenotypes of the mutants in 657 Fusarium graminearum genes encoding putative transcription factors (TFs) resulted in a database of over 11,000 phenotypes (phenome). This database provides comprehensive insights into how this cereal pathogen of global significance regulates traits important for growth, development, stress response, pathogenesis, and toxin production and how transcriptional regulations of these traits are interconnected. In-depth analysis of TFs involved in sexual development revealed that mutations causing defects in perithecia development frequently affect multiple other phenotypes, and the TFs associated with sexual development tend to be highly conserved in the fungal kingdom. Besides providing many new insights into understanding the function of F. graminearum TFs, this mutant library and phenome will be a valuable resource for characterizing the gene expression network in this fungus and serve as a reference for studying how different fungi have evolved to control various cellular processes at the transcriptional level.
PLoS Pathogens 10/2011; 7(10):e1002310. · 9.13 Impact Factor
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ABSTRACT: Geminiviruses are plant-infecting viruses with small circular single-stranded DNA genomes. These viruses utilize nuclear shuttle proteins (NSPs) and movement proteins (MPs) for trafficking of infectious DNA through the nuclear pore complex and plasmodesmata, respectively. Here, a biochemical approach was used to identify host factors interacting with the NSP and MP of the geminivirus Bean dwarf mosaic virus (BDMV). Based on these studies, we identified and characterized a host nucleoprotein, histone H3, which interacts with both the NSP and MP. The specific nature of the interaction of histone H3 with these viral proteins was established by gel overlay and in vitro and in vivo coimmunoprecipitation (co-IP) assays. The NSP and MP interaction domains were mapped to the N-terminal region of histone H3. These experiments also revealed a direct interaction between the BDMV NSP and MP, as well as interactions between histone H3 and the capsid proteins of various geminiviruses. Transient-expression assays revealed the colocalization of histone H3 and NSP in the nucleus and nucleolus and of histone H3 and MP in the cell periphery and plasmodesmata. Finally, using in vivo co-IP assays with a Myc-tagged histone H3, a complex composed of histone H3, NSP, MP, and viral DNA was recovered. Taken together, these findings implicate the host factor histone H3 in the process by which an infectious geminiviral DNA complex forms within the nucleus for export to the cell periphery and cell-to-cell movement through plasmodesmata.
Journal of Virology 09/2011; 85(22):11821-32. · 5.40 Impact Factor
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Young-Su Seo,
Jaeyun Lim,
Beom-Soon Choi,
Hongsup Kim,
Eunhye Goo,
Bongsoo Lee,
Jong-Sung Lim,
Ik-Young Choi,
Jae Sun Moon,
Jinwoo Kim,
Ingyu Hwang
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ABSTRACT: We report the complete genome sequence of Burkholderia gladioli BSR3, isolated from a diseased rice sheath in South Korea.
Journal of bacteriology 06/2011; 193(12):3149. · 3.94 Impact Factor
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Young-Su Seo,
Mawsheng Chern,
Laura E Bartley,
Muho Han,
Ki-Hong Jung,
Insuk Lee,
Harkamal Walia,
Todd Richter,
Xia Xu,
Peijian Cao, [......],
Rajeshwari Ramanan,
Fawn Amonpant,
Loganathan Arul,
Patrick E Canlas,
Randy Ruan,
Chang-Jin Park,
Xuewei Chen,
Sohyun Hwang,
Jong-Seong Jeon,
Pamela C Ronald
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ABSTRACT: Rice (Oryza sativa) is a staple food for more than half the world and a model for studies of monocotyledonous species, which include cereal crops and candidate bioenergy grasses. A major limitation of crop production is imposed by a suite of abiotic and biotic stresses resulting in 30%-60% yield losses globally each year. To elucidate stress response signaling networks, we constructed an interactome of 100 proteins by yeast two-hybrid (Y2H) assays around key regulators of the rice biotic and abiotic stress responses. We validated the interactome using protein-protein interaction (PPI) assays, co-expression of transcripts, and phenotypic analyses. Using this interactome-guided prediction and phenotype validation, we identified ten novel regulators of stress tolerance, including two from protein classes not previously known to function in stress responses. Several lines of evidence support cross-talk between biotic and abiotic stress responses. The combination of focused interactome and systems analyses described here represents significant progress toward elucidating the molecular basis of traits of agronomic importance.
PLoS Genetics 04/2011; 7(4):e1002020. · 8.69 Impact Factor
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ABSTRACT: Determination of gene function is particularly problematic when studying large-gene families because redundancy limits the ability to assess the contributions of individual genes experimentally. Phylogenomics is a phylogenetic approach used in comparative genomics to predict the biological functions of members of large gene-families by assessing the similarity among gene products. In this report, we describe the application of the Rice Kinase Database for elucidating functions of individual members of this gene family.
Trends in Plant Science 11/2010; 15(11):595-9. · 11.05 Impact Factor
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ABSTRACT: We previously characterized the rice (Oryza sativa) Submergence1 (Sub1) locus encoding three ethylene-responsive factor (ERF) transcriptional regulators. Genotypes carrying the Sub1A-1 allele are tolerant of prolonged submergence. To elucidate the mechanism of Sub1A-1-mediated tolerance, we performed transcriptome analyses comparing the temporal submergence response of Sub1A-1-containing tolerant M202(Sub1) with the intolerant isoline M202 lacking this gene. We identified 898 genes displaying Sub1A-1-dependent regulation. Integration of the expression data with publicly available metabolic pathway data identified submergence tolerance-associated pathways governing anaerobic respiration, hormone responses, and antioxidant systems. Of particular interest were a set of APETALA2 (AP2)/ERF family transcriptional regulators that are associated with the Sub1A-1-mediated response upon submergence. Visualization of expression patterns of the AP2/ERF superfamily members in a phylogenetic context resolved 12 submergence-regulated AP2/ERFs into three putative functional groups: (1) anaerobic respiration and cytokinin-mediated delay in senescence via ethylene accumulation during submergence (three ERFs); (2) negative regulation of ethylene-dependent gene expression (five ERFs); and (3) negative regulation of gibberellin-mediated shoot elongation (four ERFs). These results confirm that the presence of Sub1A-1 impacts multiple pathways of response to submergence.
Plant physiology 03/2010; 152(3):1674-92. · 6.53 Impact Factor
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ABSTRACT: The rice Xa21 gene confers immunity to most strains of the bacterium Xanthomonas oryzae pv. oryzae (Xoo). Liquid chromatography-tandem mass spectrometry analysis of biologically active fractions from Xoo supernatants led to the identification of a 194-amino acid protein designated Ax21 (activator of XA21-mediated immunity). A sulfated, 17-amino acid synthetic peptide (axY(S)22) derived from the N-terminal region of Ax21 is sufficient for activity, whereas peptides lacking tyrosine sulfation are biologically inactive. Using coimmunoprecipitation, we found that XA21 is required for axY(S)22 binding and recognition. axY(S)22 is 100% conserved in all analyzed Xanthomonas species, confirming that Ax21 is a pathogen-associated molecular pattern and that XA21 is a pattern recognition receptor.
Science 11/2009; 326(5954):850-3. · 31.20 Impact Factor
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Sang-Kyu Lee,
Min-Young Song, Young-Su Seo,
Hye-Kyung Kim,
Seho Ko,
Pei-Jian Cao,
Jung-Pil Suh,
Gihwan Yi,
Jae-Hwan Roh,
Sichul Lee,
Gynheung An,
Tae-Ryong Hahn,
Guo-Liang Wang,
Pamela Ronald,
Jong-Seong Jeon
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ABSTRACT: Rice blast, caused by the fungus Magnaporthe oryzae, is one of the most devastating diseases of rice. To understand the molecular basis of Pi5-mediated resistance to M. oryzae, we cloned the resistance (R) gene at this locus using a map-based cloning strategy. Genetic and phenotypic analyses of 2014 F2 progeny from a mapping population derived from a cross between IR50, a susceptible rice cultivar, and the RIL260 line carrying Pi5 enabled us to narrow down the Pi5 locus to a 130-kb interval. Sequence analysis of this genomic region identified two candidate genes, Pi5-1 and Pi5-2, which encode proteins carrying three motifs characteristic of R genes: an N-terminal coiled-coil (CC) motif, a nucleotide-binding (NB) domain, and a leucine-rich repeat (LRR) motif. In genetic transformation experiments of a susceptible rice cultivar, neither the Pi5-1 nor the Pi5-2 gene was found to confer resistance to M. oryzae. In contrast, transgenic rice plants expressing both of these genes, generated by crossing transgenic lines carrying each gene individually, conferred Pi5-mediated resistance to M. oryzae. Gene expression analysis revealed that Pi5-1 transcripts accumulate after pathogen challenge, whereas the Pi5-2 gene is constitutively expressed. These results indicate that the presence of these two genes is required for rice Pi5-mediated resistance to M. oryzae.
Genetics 02/2009; 181(4):1627-38. · 4.01 Impact Factor
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Xiaodong Ding,
Todd Richter,
Mei Chen,
Hiroaki Fujii, Young Su Seo,
Mingtang Xie,
Xianwu Zheng,
Siddhartha Kanrar,
Rebecca A Stevenson,
Christopher Dardick, [......],
Mawsheng Chern,
Rebecca Bart,
Xiuhua Chen,
Lihuang Zhu,
William G Farmerie,
Michael Gribskov,
Jian-Kang Zhu,
Michael E Fromm,
Pamela C Ronald,
Wen-Yuan Song
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ABSTRACT: Plants uniquely contain large numbers of protein kinases, and for the vast majority of the 1,429 kinases predicted in the rice (Oryza sativa) genome, little is known of their functions. Genetic approaches often fail to produce observable phenotypes; thus, new strategies are needed to delineate kinase function. We previously developed a cost-effective high-throughput yeast two-hybrid system. Using this system, we have generated a protein interaction map of 116 representative rice kinases and 254 of their interacting proteins. Overall, the resulting interaction map supports a large number of known or predicted kinase-protein interactions from both plants and animals and reveals many new functional insights. Notably, we found a potential widespread role for E3 ubiquitin ligases in pathogen defense signaling mediated by receptor-like kinases, particularly by the kinases that may have evolved from recently expanded kinase subfamilies in rice. We anticipate that the data provided here will serve as a foundation for targeted functional studies in rice and other plants. The application of yeast two-hybrid and TAPtag analyses for large-scale plant protein interaction studies is also discussed.
Plant physiology 01/2009; 149(3):1478-92. · 6.53 Impact Factor
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Steven Salzberg,
Daniel Sommer,
Michael Schatz,
Adam Phillippy,
Pablo Rabinowicz,
Seiji Tsuge,
Ayako Furutani,
Hirokazu Ochiai,
Arthur Delcher,
David Kelley, [......],
Shinji Tsuyumu,
Sang-Won Lee, Young-Su Seo,
Malinee Sriariyanum,
Pamela Ronald,
Ramesh Sonti,
Marie-Anne Van Sluys,
Jan Leach,
Frank White,
Adam Bogdanove
BMC Genomics 12/2008; 9(1):534. · 4.07 Impact Factor
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Ki-Hong Jung,
Jinwon Lee,
Chris Dardick, Young-Su Seo,
Peijian Cao,
Patrick Canlas,
Jirapa Phetsom,
Xia Xu,
Shu Ouyang,
Kyungsook An,
Yun-Ja Cho,
Geun-Cheol Lee,
Yoosook Lee,
Gynheung An,
Pamela C Ronald
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ABSTRACT: Functional redundancy limits detailed analysis of genes in many organisms. Here, we report a method to efficiently overcome this obstacle by combining gene expression data with analysis of gene-indexed mutants. Using a rice NSF45K oligo-microarray to compare 2-week-old light- and dark-grown rice leaf tissue, we identified 365 genes that showed significant 8-fold or greater induction in the light relative to dark conditions. We then screened collections of rice T-DNA insertional mutants to identify rice lines with mutations in the strongly light-induced genes. From this analysis, we identified 74 different lines comprising two independent mutant lines for each of 37 light-induced genes. This list was further refined by mining gene expression data to exclude genes that had potential functional redundancy due to co-expressed family members (12 genes) and genes that had inconsistent light responses across other publicly available microarray datasets (five genes). We next characterized the phenotypes of rice lines carrying mutations in ten of the remaining candidate genes and then carried out co-expression analysis associated with these genes. This analysis effectively provided candidate functions for two genes of previously unknown function and for one gene not directly linked to the tested biochemical pathways. These data demonstrate the efficiency of combining gene family-based expression profiles with analyses of insertional mutants to identify novel genes and their functions, even among members of multi-gene families.
PLoS Genetics 02/2008; 4(8):e1000164. · 8.69 Impact Factor
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Ki-Hong Jung,
Christopher Dardick,
Laura E Bartley,
Peijian Cao,
Jirapa Phetsom,
Patrick Canlas, Young-Su Seo,
Michael Shultz,
Shu Ouyang,
Qiaoping Yuan, [......],
Yi Jia,
An-Ping Hsia,
Kyungsook An,
Hui-Hsien Chou,
David Rocke,
Geun Cheol Lee,
Patrick S Schnable,
Gynheung An,
C Robin Buell,
Pamela C Ronald
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ABSTRACT: Studies of gene function are often hampered by gene-redundancy, especially in organisms with large genomes such as rice (Oryza sativa). We present an approach for using transcriptomics data to focus functional studies and address redundancy. To this end, we have constructed and validated an inexpensive and publicly available rice oligonucleotide near-whole genome array, called the rice NSF45K array. We generated expression profiles for light- vs. dark-grown rice leaf tissue and validated the biological significance of the data by analyzing sources of variation and confirming expression trends with reverse transcription polymerase chain reaction. We examined trends in the data by evaluating enrichment of gene ontology terms at multiple false discovery rate thresholds. To compare data generated with the NSF45K array with published results, we developed publicly available, web-based tools (www.ricearray.org). The Oligo and EST Anatomy Viewer enables visualization of EST-based expression profiling data for all genes on the array. The Rice Multi-platform Microarray Search Tool facilitates comparison of gene expression profiles across multiple rice microarray platforms. Finally, we incorporated gene expression and biochemical pathway data to reduce the number of candidate gene products putatively participating in the eight steps of the photorespiration pathway from 52 to 10, based on expression levels of putatively functionally redundant genes. We confirmed the efficacy of this method to cope with redundancy by correctly predicting participation in photorespiration of a gene with five paralogs. Applying these methods will accelerate rice functional genomics.
PLoS ONE 02/2008; 3(10):e3337. · 4.09 Impact Factor
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Steven L Salzberg,
Daniel D Sommer,
Michael C Schatz,
Adam M Phillippy,
Pablo D Rabinowicz,
Seiji Tsuge,
Ayako Furutani,
Hirokazu Ochiai,
Arthur L Delcher,
David Kelley, [......],
Shinji Tsuyumu,
Sang Won Lee, Young-Su Seo,
Malinee Sriariyanum,
Pamela C Ronald,
Ramesh V Sonti,
Marie-Anne Van Sluys,
Jan E Leach,
Frank F White,
Adam J Bogdanove
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ABSTRACT: Xanthomonas oryzae pv. oryzae causes bacterial blight of rice (Oryza sativa L.), a major disease that constrains production of this staple crop in many parts of the world. We report here on the complete genome sequence of strain PXO99A and its comparison to two previously sequenced strains, KACC10331 and MAFF311018, which are highly similar to one another.
The PXO99A genome is a single circular chromosome of 5,240,075 bp, considerably longer than the genomes of the other strains (4,941,439 bp and 4,940,217 bp, respectively), and it contains 5083 protein-coding genes, including 87 not found in KACC10331 or MAFF311018. PXO99A contains a greater number of virulence-associated transcription activator-like effector genes and has at least ten major chromosomal rearrangements relative to KACC10331 and MAFF311018. PXO99A contains numerous copies of diverse insertion sequence elements, members of which are associated with 7 out of 10 of the major rearrangements. A rapidly-evolving CRISPR (clustered regularly interspersed short palindromic repeats) region contains evidence of dozens of phage infections unique to the PXO99A lineage. PXO99A also contains a unique, near-perfect tandem repeat of 212 kilobases close to the replication terminus.
Our results provide striking evidence of genome plasticity and rapid evolution within Xanthomonas oryzae pv. oryzae. The comparisons point to sources of genomic variation and candidates for strain-specific adaptations of this pathogen that help to explain the extraordinary diversity of Xanthomonas oryzae pv. oryzae genotypes and races that have been isolated from around the world.
BMC Genomics 02/2008; 9:204. · 4.07 Impact Factor
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ABSTRACT: Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc) are bacterial pathogens of the worldwide staple and grass model, rice. Xoo and Xoc are closely related but Xoo invades rice vascular tissue to cause bacterial leaf blight, a serious disease of rice in many parts of the world, and Xoc colonizes the mesophyll parenchyma to cause bacterial leaf streak, a disease of emerging importance. Both pathogens depend on hrp genes for type III secretion to infect their host. We constructed a 50-70 mer oligonucleotide microarray based on available genome data for Xoo and Xoc and compared gene expression in Xoo strains PXO99A and Xoc strain BLS256 grown in the rich medium PSB vs. XOM2, a minimal medium previously reported to induce hrp genes in Xoo strain T7174.
Three biological replicates of the microarray experiment to compare global gene expression in representative strains of Xoo and Xoc grown in PSB vs. XOM2 were carried out. The non-specific error rate and the correlation coefficients across biological replicates and among duplicate spots revealed that the microarray data were robust. 247 genes of Xoo and 39 genes of Xoc were differentially expressed in the two media with a false discovery rate of 5% and with a minimum fold-change of 1.75. Semi-quantitative-RT-PCR assays confirmed differential expression of each of 16 genes each for Xoo and Xoc selected for validation. The differentially expressed genes represent 17 functional categories.
We describe here the construction and validation of a two-genome microarray for the two pathovars of X. oryzae. Microarray analysis revealed that using representative strains, a greater number of Xoo genes than Xoc genes are differentially expressed in XOM2 relative to PSB, and that these include hrp genes and other genes important in interactions with rice. An exception was the rax genes, which are required for production of the host resistance elicitor AvrXa21, and which were expressed constitutively in both pathovars.
BMC Microbiology 02/2008; 8:99. · 3.04 Impact Factor
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ABSTRACT: The HSP90 (heat shock protein 90), SGT1 (suppressor of G-two allele ofSkp1), and RAR1 (required forMla12 resistance) proteins in plants form a molecular chaperone complex which is involved in diverse biological signaling including
development and disease resistance. The three components of this complex interact via specific protein binding motifs and
recruit client proteins to initiate a specific signaling cascade in response to cellular or environmental cues. Although the
functions of this chaperone complex during development/growth have not been well characterized, the HSP90 chaperone and SGT1
and RAR1 co-chaperones have been demonstrated to be essential signaling components of plant immune responses. These three
proteins also play important roles in activation of the mammalian Nod genes, which possess a structurally conserved plant
resistance (R) protein motif, NB-LRR (nucleotide binding site-leucine rich repeat). In this review, we summarize the structures
and functions of these molecular chaperones, and discuss their putative modes of action in plant immune responses.
Journal of Plant Biology 12/2007; 51(1):1-10. · 1.07 Impact Factor
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ABSTRACT: SUMMARY Common bean (Phaseolus vulgaris L.) cultivar (cv.) Othello develops a hypersensitive response-associated vascular resistance to infection by Bean dwarf mosaic virus (BDMV), a single-stranded DNA virus (genus Begomovirus, family Geminiviridae). A PCR-based cDNA subtraction approach was used to identify genes involved in this resistance response. Eighteen clones, potentially involved with BDMV resistance, were identified based upon being up-regulated in BDMV-infected tissues and/or having sequence similarity with known resistance-associated genes. Analysis of these clones revealed potential genes involved in pathogen defence, including pathogenesis-related protein genes and resistance gene analogues (RGAs). Further characterization of one RGA, F1-10, revealed that it encodes a predicted protein with a double Toll/interleukin-1 receptor (TIR) motif. Full-length (F1-10) and spliced (F1-10sp) forms of the RGA were strongly up-regulated in BDMV-infected cv. Othello hypocotyl tissues by 4 days post-inoculation, but not in equivalent mock-inoculated tissues. In agroinfiltration experiments, F1-10, but not F1-10sp, mediated resistance to BDMV in the susceptible common bean cv. Topcrop. By contrast, transgenic Nicotiana benthamiana lines expressing F1-10 or F1-10sp were not resistant to BDMV. Interestingly, when these transgenic lines were inoculated with the potyvirus Bean yellow mosaic virus, some F1-10 lines showed a more severe symptom phenotype compared with non-transgenic control plants. Based on these findings, F1-10 was named: Phaseolus vulgaris VIRUS response TIR-TIR GENE 1 (PvVTT1).
Molecular Plant Pathology 03/2007; 8(2):151-62. · 3.90 Impact Factor
