The Experts below are selected from a list of 7542 Experts worldwide ranked by ideXlab platform
Adam J Bogdanove - One of the best experts on this subject based on the ideXlab platform.
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Novel Candidate Virulence Factors in Rice Pathogen Xanthomonas oryzae pv. oryzicola as Revealed by Mutational Analysis
Applied and environmental microbiology, 2007Co-Authors: Li Wang, Seiko Makino, Ashim Subedee, Adam J BogdanoveAbstract:Bacterial leaf streak, caused by Xanthomonas oryzae pv. oryzicola, is an important disease of rice. Transposon-mediated mutational analysis of the pathogen with a quantitative assay revealed candidate virulence factors including genes involved in the pathogenesis of other phytopathogenic bacteria, virulence factors of animal pathogens, and genes not previously associated with virulence.
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Xanthomonas oryzae pathovars model pathogens of a model crop
Molecular Plant Pathology, 2006Co-Authors: David O Ninoliu, Pamela C Ronald, Adam J BogdanoveAbstract:SUMMARY Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola cause bacterial blight and bacterial leaf streak of rice (Oryza sativa), which constrain production of this staple crop in much of Asia and parts of Africa. Tremendous progress has been made in characterizing the diseases and breeding for resistance. X. oryzae pv. oryzae causes bacterial blight by invading the vascular tissue, while X. oryzae pv. oryzicola causes bacterial leaf streak by colonizing the parenchyma. In rice there are 29 major genes for resistance to bacterial blight, but so far only a few quantitative resistance loci for bacterial leaf streak. Over 30 races of X. oryzae pv. oryzae have been reported. Both pathogens exhibit genetic variation among isolates. Mechanisms of pathogenesis and resistance have begun to be elucidated. Members of the AvrBs3/PthA family of transcription activator-like effectors play a major role in the virulence of X. oryzae pv. oryzae and possibly X. oryzae pv. oryzicola. Cloning of six rice resistance genes for bacterial blight and one from maize effective against bacterial leaf streak has uncovered a diversity of structure and function, some shared by genes involved in defence in animals. This article reviews research that spans a century. It also presents a perspective on challenges for sustainable control, and opportunities that interactions of X. oryzae pathovars with rice present as models for understanding fundamental aspects of bacterial pathogenesis of plants and plant disease resistance, as well as other aspects of plant and microbial biology, with implications also for animal innate immunity.
Wang Jin-sheng - One of the best experts on this subject based on the ideXlab platform.
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Production and localization of endogenous hydrogen peroxide in Xanthomonas oryzae pv.oryzae
Journal of Nanjing Agricultural University, 2009Co-Authors: Wang Jin-shengAbstract:Production and localization of endogenous hydrogen peroxide(H2O2)were investigated in strains of Xanthomonas oryzae pv.oryzae using horseradish peroxidase(HRP)-red phenol assay or by histochemical analysis under transmission electron microscopy.Experiments identified the endogenous H2O2 production in nearly all strains tested.Levels of endogenous H2O2 production were different among these strains,and the accumulated H2O2 was mainly localized in the cell wall,while the H2O2 accumulation was undetectable in plasma membrane or cytoplasm of bacterial cells.
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Knock-out of pathogenicity-related genes in Xanthomonas oryzae pv. oryzicola and Xanthomonas oryzae pv.oryzae
Journal of Nanjing Agricultural University, 2006Co-Authors: Wang Jin-shengAbstract:wxocA,wxocB,wxocD,wxocE and wzt are genes for lipopolysaccharide(LPS)biosynthesis in Xanthomonas oryzae pv.oryzicola(Xooc),and avrXa3 is an avirulence(avr)gene in Xanthomonas oryzae pv.oryzae(Xoo).Plasmids pBCSK(-)and pKNG101 with replicon of ColE1 and R6K,respectively,were used to construct gene knock-out transformation units.Transformation units of pBCSK∷ΔwxocA,pBCSK∷ΔwxocD,pBCSK∷ΔwxocE and PBCSK∷Δwzt to produce Xooc strain PS105 corresponding gene mutants were constructed with two fragments:central portion of target gene and pBCSK(-) vector.Transformation units of pKNG101∷ΔwxocB and pKNG101∷Δavr to produce wxocB mutant of Xooc strain RS105 and avirulence gene mutant in Xoo strain PXO99 were constructed with four fragments :pKNG101 vector,two flanking sequences of corresponding gene,and cm gene.Transformation was conducted by electroporation to yield 5 lps gene mutants(MwxocA,MwxocB,MwxocD,MwxocE,Mwzt)and 1 avr gene mutant(PXO99Δavr),and homologous recombinations were confirmed by Southern blot.The analysis of LPS by SDS-PAGE showed that all the lps gene mutants had defects in O-antigen biosynthesis.Virulence tests indicated that pathogenicity of MwxocB and MwxocE were completely lost and Mwzt was reduced.And PXO99Δavr showed less virulence on IRBB50(Xa4/xa5)and Asominori(Xa17).Therefore,the vectors pBCSK(-)and pKNG101 were first confirmed to be successfully used to knock-out genes in Xooc and Xoo and be helpful to identify the functions of pathogenicity-related genes in Xooc and Xoo.
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avr/pth13 Gene of Xanthomonas oryzae pv. oryzicola, a Novel Virulence Member of avrBs3/PthA Family, Strengthening Virulence of Xanthomonas oryzae pv. oryzae on Rice
Chinese Journal of Rice Science, 2005Co-Authors: Wang Jin-shengAbstract:An EcoRⅠ-BamHⅠ DNA, corresponding to the coding region NLS (nuclear localization signal) and AD (acidic transcriptional activation domain) of AvrXa3 of Xanthomonas oryzae pv. oryzae (Xoo), was used as a probe to screen the genomic library of Xanthomonas oryzae pv. oryzicola(Xooc). One avrBs3/PthA gene clone was obtained after positive clones of the library were digested by EcoRⅠ endoenzyme and proved by Southern blot. Sequencing subclone, pPth13, indicated that it contained a gene belonging to the avrBs3/PthA family of Xanthomonas pathogenic bacteria, and was nominated as avr/pth13 gene. As other AvrBs3/PthA, the putative protein of avr/pth13 gene possesses the same 5’- and 3’- terminals, one leucine zipper (LZ), three NLSs and one AD. However, the difference of the gene with other avrBs3/PthA family members was the repeat numbers of 34 amino acid unit coded by 102 bp repeat. The 102 bp unit was repeated 5.5 times in avr/pth13 gene. Blasting the sequence in GenBank database showed that avr/pth13 gene was the smallest in avrBs3/PthA family. (Alignment) of 12-13~(th) residues in 34 amino acid unit of Avr/Pth13 with those of other AvrBs3/PthA proteins demonstrated that at least three HD(His and Asp) residues in 12-13~(th) position of 34 amino acid unit might be necessary for avirulence or/and virulence. Pathogenicity tests of strain PXO99~(A )containing avr/pth13gene on near isogenic lines (NILs) of rice showed that avr/pth13 gene strengthened the virulence of Xoo on the tested NILs. All the above confirmed that avrBs3/PthA gene(s) existed in Xooc as that in Xoo, determining virulence in bacterial streak and blight diseases of rice.
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Molecular genetics of pathogenicity determinants of {\sl Xanthomonas oryzae} pv. {\sl oryzae}
2004Co-Authors: Chen Gongyou, Zou Lifang, Wang Xingping, Xiang Yong, Wang Jin-shengAbstract:Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of bacterial blight disease in rice. The Xoo-Rice interaction is consistent with the gene-for-gene hypothesis and is an ideal model system for understanding mechanisms of molecular plant-pathogen interactions. In the last decade, important pathogenicity-related genes of Xoo had been cloned and identified. Genomic bioinformatics of other gram-negative plant bacterial pathogens, including other Xanthomonas species, has facilitated research on molecular pathogenicity determinants of Xoo, especially on mining TTSS (type III secretion system) effectors. A brief review on the current knowledge of the molecular mechanisms of Xoo pathogenicity is made in order to provide a basis for functional genomics of molecular rice-Xoo interactions.Molecular Genetics of Pathogenicity Determinants of Xanthomonas oryzae pv. oryzae CHEN Gong-you, ZOU Li-fang, WANG Xing-ping, XIANG Yong, WANG Jin-sheng (Key Laboratory for Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095) Abstract: Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of bacterial blight disease in rice. The Xoo-Rice interaction is consistent with the gene-for-gene hypothesis and is an ideal model system for understanding mechanisms of molecular plant-pathogen interactions. In the last decade, important pathogenicity-related genes of Xoo had been cloned and identified. Genomic bioinformatics of other gram-negative plant bacterial pathogens, including other Xanthomonas species, has facilitated research on molecular pathogenicity determinants of Xoo, especially on mining TTSS (type III secretion system) effectors. A brief review on the current knowledge of the molecular mechanisms of Xoo pathogenicity is made in order to provide a basis for functional genomics of molecular rice-Xoo interactions. Key words: Rice; Xanthomonas oryzae pv. oryzae; Pathogenicity determinant; Hypersensitive response; Type III secretion system
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Purification and characteristics of a harpin-like protein from Xanthomonas oryzae pv. oryzicola
2004Co-Authors: Wang Jin-shengAbstract:A proteinaceous elicitor which could induce hypersensitive response (HR) reaction on tobacco was purified by (NH4)2SO4 precipitation, ultra speed centrifugation, preparative IEF and ion exchange techniques from cells of strain M51, an hrp mutant of the wild type RS105 (Xanthomonas oryzae pv. oryzicola, Xooc). The molecular weight of this protein was 25. 5 kDa determined by 15% SDS-PAGE. It possessed many similarities with HarpinEa(from Erwinia arnylovora) and HarpinXoo(from Xanthomonas oryzae pv. oryzae, Xoo) in physical and biological properties. This protein was heat-stable and sensitive to protease K. It also could elicit a typical HR reaction on tobacco leaves, which was dispelled by eu-karyotic metabolic inhibitors: actinomycin D, cycloheximide and LaCl3. We also found that the protein had the ability to induce disease-resistance to TMV when sprayed on tobacco. Thus, the protein is designated as HLPxooc(Harpin-like protein).
Valérie Verdier - One of the best experts on this subject based on the ideXlab platform.
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The Genomics of Xanthomonas oryzae
Genomics of Plant-Associated Bacteria, 2014Co-Authors: Lindsay R. Triplett, Valérie Verdier, Ralf Koebnik, Jan E. LeachAbstract:Xanthomonas oryzae pathovars oryzae and oryzicola cause bacterial leaf blight and bacterial leaf streak of rice, respectively, two diseases that pose a significant threat to global rice yields. The first four complete genome sequences of X. oryzae strains yielded a wealth of information about virulence factor content, mobile genetic elements, and taxonomic differences among strains of X. oryzae pathovars oryzae and oryzicola. The genomes have been applied in systematic studies of gene function and expression and in comparative analyses of the differences between pathovars. X. oryzae genome sequences facilitated the current understanding of the evolutionary history and diversity of type III secreted effectors, including transcriptional activator-like (TAL) effectors, and contributed to the discovery of the code-mediating TAL effector recognition specificity. The genomes have also been instrumental in the development of improved tools for epidemiological typing and disease diagnostics. This chapter focuses on the contributions of genomic sequencing projects to the understanding of X. oryzae biology and diversity and the future questions that genomics will help address.
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In planta gene expression analysis of Xanthomonas oryzae pathovar oryzae, African strain MAI1.
BMC microbiology, 2010Co-Authors: Mauricio Soto-suárez, Diana Bernal, Carolina González, Boris Szurek, Romain Guyot, Joe Tohme, Valérie VerdierAbstract:Bacterial leaf blight causes significant yield losses in rice crops throughout Asia and Africa. Although both the Asian and African strains of the pathogen, Xanthomonas oryzae pv. oryzae (Xoo), induce similar symptoms, they are nevertheless genetically different, with the African strains being more closely related to the Asian X. oryzae pv. oryzicola (Xoc).
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Molecular and pathotypic characterization of new Xanthomonas oryzae strains from West Africa
Molecular Plant-Microbe Interactions, 2007Co-Authors: Carolina González, Boris Szurek, Charles Manceau, Thierry Mathieu, Yacouba Séré, Valérie VerdierAbstract:DNA polymorphism analysis and pathogenicity assays were used to characterize strains of Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola collected from rice leaves in West Africa. Restriction fragment length polymorphism (RFLP), repetitive sequence-based polymerase chain reaction, fluorescent amplified fragment-length polymorphism (FAFLP) analyses were assessed for molecular characterization, while pathogenicity was tested by leaf clipping and leaf infiltration. Dendrograms were generated for the data sets obtained from RFLP analysis and repetitive polymerase chain reaction suggesting that the interrelationships between strains were dependent on the technique used. In all cases, data showed that African strains of X. oryzae pv. oryzae form a group genetically distant from Asian strains. FAFLP analyses separated the X. oryzae strains into three groups with significant bootstrap values. A specific and intriguing feature of African strains of X. oryzae pv. oryzae is a reduction in the number of insertion sequence elements and transcription activator-like (avrBs3/pthA) effector genes, based on the molecular markers employed in the study. In addition, pathogenicity assays conducted with African strains of X. oryzae pv. oryzae on a series of nearly isogenic lines (NILs) identified three new races. Finally, leaf infiltration assays revealed the capacity of African strains of X. oryzae pv. oryzae to induce a nonhost hypersensitive response in Nicotiana benthamiana, in contrast with Asian X. oryzae pv. oryzae and X. oryzae pv. oryzicola strains. Our results reveal substantial differences between genomic characteristics of Asian and African strains of X. oryzae pv. oryzae
Junhua Peng - One of the best experts on this subject based on the ideXlab platform.
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Resistance Genes and their Interactions with Bacterial Blight/Leaf Streak Pathogens ( Xanthomonas oryzae ) in Rice ( Oryza sativa L.)—an Updated Review
Rice (New York N.Y.), 2020Co-Authors: Jiang Nan, Jun Yan, Shi Yanlong, He Zhizhou, Qin Zeng, Xionglun Liu, Junhua PengAbstract:Rice (Oryza sativa L.) is a staple food crop, feeding more than 50% of the world’s population. Diseases caused by bacterial, fungal, and viral pathogens constantly threaten the rice production and lead to enormous yield losses. Bacterial blight (BB) and bacterial leaf streak (BLS), caused respectively by gram-negative bacteria Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc), are two important diseases affecting rice production worldwide. Due to the economic importance, extensive genetic and genomic studies have been conducted to elucidate the molecular mechanism of rice response to Xoo and Xoc in the last two decades. A series of resistance (R) genes and their cognate avirulence and virulence effector genes have been characterized. Here, we summarize the recent advances in studies on interactions between rice and the two pathogens through these R genes or their products and effectors. Breeding strategies to develop varieties with durable and broad-spectrum resistance to Xanthomonas oryzae based on the published studies are also discussed.
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resistance genes and their interactions with bacterial blight leaf streak pathogens Xanthomonas oryzae in rice oryza sativa l an updated review
Rice, 2020Co-Authors: Jun Yan, Qin Zeng, Xionglun Liu, Junhua Peng, Nan Jiang, Yi Liang, Yanlong ShiAbstract:Rice (Oryza sativa L.) is a staple food crop, feeding more than 50% of the world’s population. Diseases caused by bacterial, fungal, and viral pathogens constantly threaten the rice production and lead to enormous yield losses. Bacterial blight (BB) and bacterial leaf streak (BLS), caused respectively by gram-negative bacteria Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc), are two important diseases affecting rice production worldwide. Due to the economic importance, extensive genetic and genomic studies have been conducted to elucidate the molecular mechanism of rice response to Xoo and Xoc in the last two decades. A series of resistance (R) genes and their cognate avirulence and virulence effector genes have been characterized. Here, we summarize the recent advances in studies on interactions between rice and the two pathogens through these R genes or their products and effectors. Breeding strategies to develop varieties with durable and broad-spectrum resistance to Xanthomonas oryzae based on the published studies are also discussed.
Jan E. Leach - One of the best experts on this subject based on the ideXlab platform.
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The Genomics of Xanthomonas oryzae
Genomics of Plant-Associated Bacteria, 2014Co-Authors: Lindsay R. Triplett, Valérie Verdier, Ralf Koebnik, Jan E. LeachAbstract:Xanthomonas oryzae pathovars oryzae and oryzicola cause bacterial leaf blight and bacterial leaf streak of rice, respectively, two diseases that pose a significant threat to global rice yields. The first four complete genome sequences of X. oryzae strains yielded a wealth of information about virulence factor content, mobile genetic elements, and taxonomic differences among strains of X. oryzae pathovars oryzae and oryzicola. The genomes have been applied in systematic studies of gene function and expression and in comparative analyses of the differences between pathovars. X. oryzae genome sequences facilitated the current understanding of the evolutionary history and diversity of type III secreted effectors, including transcriptional activator-like (TAL) effectors, and contributed to the discovery of the code-mediating TAL effector recognition specificity. The genomes have also been instrumental in the development of improved tools for epidemiological typing and disease diagnostics. This chapter focuses on the contributions of genomic sequencing projects to the understanding of X. oryzae biology and diversity and the future questions that genomics will help address.
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A homolog of an Escherichia coli phosphate-binding protein gene from Xanthomonas oryzae pv. oryzae
DNA Sequence, 1995Co-Authors: Frank F. White, L. A. Heaton, James A. Guikema, Jan E. LeachAbstract:A Xanthomonas oryzae pv. oryzae gene with sequence similarity to an Escherichia coli phosphate-binding protein gene (phoS) produces a periplasmic protein of apparent M(r) 35,000 when expressed in E. coli. Amino terminal sequencing revealed that a signal peptide is removed during transport to the periplasm in E. coli.
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Population biology of Xanthomonas oryzae pv. oryzae and approaches to its control
Current Opinion in Biotechnology, 1995Co-Authors: Jan E. Leach, Hei Leung, Rebecca J. Nelson, T. W. MewAbstract:Abstract New insights into the population structure of Xanthomonas oryzae pv. oryzae, the pathogen causing bacterial blight of rice, have been achieved through the use of molecular markers in combination with virulence typing. A hierarchical analysis to evaluate diversity and structure of X. oryzae pv. oryzae populations between countries, between different agro-ecosystems, and within and between farmer's fields has revealed differentiation of subpopulations on various spatial scales. Such information on the pathogen populations might be used to refine disease management strategies and to investigate pathogen evolution.
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Physiology of resistant interactions between Xanthomonas oryzae pv. oryzae and rice
Developments in Plant Pathology, 1994Co-Authors: Jan E. Leach, Ailan Guo, P.j. Reimers, Seong Ho Choi, C M Hopkins, Frank F. WhiteAbstract:Resistant interactions between Xanthomonas oryzae pv. oryzae and rice are characterized by increases in the activities of three extracellular peroxidases (two anionic and one cationic), lignin deposition, host cell death, and a decrease in the rate of bacterial multiplication. The timing and dynamics of these events is dependent on the specific avirulence gene-resistance gene interaction. In susceptible interactions, increases in peroxidase activity, lignin deposition, and host cell death are delayed, and bacterial multiplication is not inhibited. In the absence of light, the events associated with resistance do not occur, and a response similar to the susceptible response is observed.
