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Articles 181 - 199 of 199
Full-Text Articles in Plant Pathology
Intergenic Transcription By Rna Polymerase Ii Coordinates Pol Iv And Pol V In Sirna-Directed Transcriptional Gene Silencing In Arabidopsis, Binglian Zheng, Zhengming Wang, Shengben Li, Bin Yu, Jin -Yuan Liu, Xuemei Chen
Intergenic Transcription By Rna Polymerase Ii Coordinates Pol Iv And Pol V In Sirna-Directed Transcriptional Gene Silencing In Arabidopsis, Binglian Zheng, Zhengming Wang, Shengben Li, Bin Yu, Jin -Yuan Liu, Xuemei Chen
Center for Plant Science Innovation: Faculty Publications
Intergenic transcription by RNA Polymerase II (Pol II) is widespread in plant and animal genomes, but the functions of intergenic transcription or the resulting noncoding transcripts are poorly understood. Here, we show that Arabidopsis Pol II is indispensable for endogenous siRNA-mediated transcriptional gene silencing (TGS) at intergenic low-copy-number loci, despite the presence of two other polymerases—Pol IV and Pol V—that specialize in TGS through siRNAs. We show that Pol II produces noncoding scaffold transcripts that originate outside of heterochromatic, siRNA-generating loci. Through these transcripts and physical interactions with the siRNA effector protein ARGONAUTE4 (AGO4), Pol II recruits AGO4/siRNAs to homologous …
Phytopathogen Type Iii Effector Weaponry And Their Plant Targets, Anna Block, Guangyong Li, Zheng Qing Fu, James R. Alfano
Phytopathogen Type Iii Effector Weaponry And Their Plant Targets, Anna Block, Guangyong Li, Zheng Qing Fu, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
Phytopathogenic bacteria suppress plant innate immunity and promote pathogenesis by injecting proteins called type III effectors into plant cells using a type III protein secretion system. These type III effectors use at least three major strategies to alter host responses. One strategy is to alter host protein turnover, either by direct cleavage or by modulating ubiquitination and targeting to the 26S proteasome. Another strategy involves alteration of RNA metabolism by transcriptional activation or ADP-ribosylation of RNA-binding proteins. A third major strategy is to inhibit the kinases involved in plant defence signalling, either by removing phosphates or by direct inhibition. The …
The Small Glycine-Rich Rna Binding Protein Atgrp7 Promotes Floral Transition In Arabidopsis Thaliana, Corinna Streitner, Selahattin Danisman, Franziska Wehrle, Jan C. Schoning, James R. Alfano, Dorothee Staiger
The Small Glycine-Rich Rna Binding Protein Atgrp7 Promotes Floral Transition In Arabidopsis Thaliana, Corinna Streitner, Selahattin Danisman, Franziska Wehrle, Jan C. Schoning, James R. Alfano, Dorothee Staiger
Center for Plant Science Innovation: Faculty Publications
The RNA binding protein AtGRP7 is part of a circadian slave oscillator in Arabidopsis thaliana that negatively autoregulates its own mRNA, and affects the levels of other transcripts. Here, we identify a novel role for AtGRP7 as a flowering-time gene. An atgrp7-1 T-DNA mutant flowers later than wild-type plants under both long and short days, and independent RNA interference lines with reduced levels of AtGRP7, and the closely related AtGRP8 protein, are also late flowering, particularly in short photoperiods. Consistent with the retention of a photoperiodic response, the transcript encoding the key photoperiodic regulator CONSTANS oscillates with a similar pattern …
A Pseudomonas Syringae Pv. Tomato Dc3000 Mutant Lacking The Type Iii Effector Hopq1-1 Is Able To Cause Disease In The Model Plant Nicotiana Benthamiana, Chia-Fong Wei, Brian H. Kvitko, Rena Shimizu, Emerson Crabill, James R. Alfano, Nai-Chun Lin, Gregory B. Martin, Hsiou-Chen Huang, Alan Collmer
A Pseudomonas Syringae Pv. Tomato Dc3000 Mutant Lacking The Type Iii Effector Hopq1-1 Is Able To Cause Disease In The Model Plant Nicotiana Benthamiana, Chia-Fong Wei, Brian H. Kvitko, Rena Shimizu, Emerson Crabill, James R. Alfano, Nai-Chun Lin, Gregory B. Martin, Hsiou-Chen Huang, Alan Collmer
Center for Plant Science Innovation: Faculty Publications
The model pathogen Pseudomonas syringae pv. tomato DC3000 causes bacterial speck in tomato and Arabidopsis, but Nicotiana benthamiana, an important model plant, is considered to be a non-host. Strain DC3000 injects approximately 28 effector proteins into plant cells via the type III secretion system (T3SS). These proteins were individually delivered into N. benthamiana leaf cells via T3SS-proficient Pseudomonas fluorescens, and eight, including HopQ1-1, showed some capacity to cause cell death in this test. Four gene clusters encoding 13 effectors were deleted from DC3000: cluster II (hopH1, hopC1), IV (hopD1, hopQ1-1, hopR1), IX (hopAA1-2, hopV1, hopAO1, hopG1), and native plasmid pDC3000A …
Pseudomonas SyringaeHrpj Is A Type Iii Secreted Protein That Is Required For Plant Pathogenesis, Injection Of Effectors,And Secretion Of The Hrpz1 Harpin, Zheng Qing Fu, Ming Guo, James R. Alfano
Pseudomonas SyringaeHrpj Is A Type Iii Secreted Protein That Is Required For Plant Pathogenesis, Injection Of Effectors,And Secretion Of The Hrpz1 Harpin, Zheng Qing Fu, Ming Guo, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
The bacterial plant pathogen Pseudomonas syringae requires a type III protein secretion system (TTSS) to cause disease. The P. syringae TTSS is encoded by the hrp-hrc gene cluster. One of the genes within this cluster, hrpJ, encodes a protein with weak similarity to YopN, a type III secreted protein from the animal pathogenic Yersinia species. Here, we show that HrpJ is secreted in culture and translocated into plant cells by the P. syringae pv. tomato DC3000 TTSS. A DC3000 hrpJ mutant, UNL140, was greatly reduced in its ability to cause disease symptoms and multiply in Arabidopsis thaliana …
A Highly Efficient Transient Protoplast System For Analyzing Defence Gene Expression And Protein–Protein Interactions In Rice, Songbiao Chen, Lizen Tao, Lirong Zeng, Miguel E. Vega-Zanchez, Kenji Umemura, Guo-Liang Wang
A Highly Efficient Transient Protoplast System For Analyzing Defence Gene Expression And Protein–Protein Interactions In Rice, Songbiao Chen, Lizen Tao, Lirong Zeng, Miguel E. Vega-Zanchez, Kenji Umemura, Guo-Liang Wang
Center for Plant Science Innovation: Faculty Publications
The transient assay system based on mesophyll or cultured cell-derived protoplasts has been exploited in several plant species and has become a powerful tool for rapid gene functional analysis and biochemical manipulations. However, the system has not been widely used in rice owing to the difficulties in large-scale isolation of viable rice protoplasts from leaves or suspension-cultured cells. Here, we describe a significantly improved method to isolate a large number of protoplasts from stem and sheath tissues of both young and mature plants. High-level coexpression of multiple constructs and efficient suppression of exogenous and endogenous genes were observed in the …
Pseudomonas Syringae Type Iii Chaperones Shco1, Shcs1, And Shcs2 Facilitate Translocation Of Their Cognate Effectors And Can Substitute For Each Other In The Secretion Of Hopo1-1, Ming Guo, Scott T. Chancey, Fang Tian, Zhengxiang Ge, Yashitola Jamir, James R. Alfano
Pseudomonas Syringae Type Iii Chaperones Shco1, Shcs1, And Shcs2 Facilitate Translocation Of Their Cognate Effectors And Can Substitute For Each Other In The Secretion Of Hopo1-1, Ming Guo, Scott T. Chancey, Fang Tian, Zhengxiang Ge, Yashitola Jamir, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
The Pseudomonas syringae type III secretion system (TTSS) translocates effector proteins into plant cells. Several P. syringae effectors require accessory proteins called type III chaperones (TTCs) to be secreted via the TTSS. We characterized the hopO1-1, hopS1, and hopS2 operons in P. syringae pv. tomato DC3000; these operons encode three homologous TTCs, ShcO1, ShcS1, and ShcS2. ShcO1, ShcS1, and ShcS2 facilitated the type III secretion and/or translocation of their cognate effectors HopO1-1, HopS1, and HopS2, respectively. ShcO1 and HopO1-1 interacted with each other in yeast two-hybrid and coimmunoprecipitation assays. Interestingly, ShcS1 and ShcS2 were capable of substituting for …
The Hrpk Operon Of Pseudomonas Syringae Pv. Tomato Dc3000 Encodes Two Proteins Secreted By The Type Iii (Hrp) Protein Secretion System: Hopb1 And Hrpk, A Putative Type Iii Translocator, Tanja Petnicki-Ocwieja, Karin V. Van Dijk, James R. Alfano
The Hrpk Operon Of Pseudomonas Syringae Pv. Tomato Dc3000 Encodes Two Proteins Secreted By The Type Iii (Hrp) Protein Secretion System: Hopb1 And Hrpk, A Putative Type Iii Translocator, Tanja Petnicki-Ocwieja, Karin V. Van Dijk, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
Pseudomonas syringae is a gram-negative bacterial plant pathogen that is dependent on a type III protein secretion system (TTSS) and the effector proteins it translocates into plant cells for pathogenicity. The P. syringae TTSS is encoded by hrp-hrc genes that reside in a central region of a pathogenicity island (Pai). Flanking one side of this Pai is the exchangeable effector locus (EEL). We characterized the transcriptional expression of the open reading frames (ORFs) within the EEL of P. syringae pv. tomato DC3000. One of these ORFs, PSPTO1406 (hopB1) is expressed in the same transcriptional unit as hrpK. …
Disabling Surveillance: Bacterial Type Iii Secretion System Effectors That Suppress Innate Immunity, Avelina Espinosa, James R. Alfano
Disabling Surveillance: Bacterial Type Iii Secretion System Effectors That Suppress Innate Immunity, Avelina Espinosa, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
Many Gram-negative bacterial pathogens of plants and animals are dependent on a type III protein secretion system (TTSS). TTSSs translocate effector proteins into host cells and are capable of modifying signal transduction pathways. The innate immune system of eukaryotes detects the presence of pathogens using specific pathogen recognition receptors (PRRs). Plant PRRs include the FLS2 receptor kinase and resistance proteins. Animal PRRs include Tolllike receptors and nucleotide-binding oligomerization domain proteins. PRRs initiate signal transduction pathways that include mitogen-activated protein kinase (MAPK) cascades that activate defencerelated transcription factors. This results in induction of proinflammatory cytokines in animals, and hallmarks of defence …
The Pseudomonas Syringae Hopptov Protein Is Secreted In Culture And Translocated Into Plant Cells Via The Type Iii Protein Secretion System In A Manner Dependent On The Shcv Type Iii Chaperone, Misty D. Wehling, Ming Guo, Zheng Qing Fu, James R. Alfano
The Pseudomonas Syringae Hopptov Protein Is Secreted In Culture And Translocated Into Plant Cells Via The Type Iii Protein Secretion System In A Manner Dependent On The Shcv Type Iii Chaperone, Misty D. Wehling, Ming Guo, Zheng Qing Fu, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
The bacterial plant pathogen Pseudomonas syringae depends on a type III protein secretion system and the effector proteins that it translocates into plant cells to cause disease and to elicit the defense-associated hypersensitive response on resistant plants. The availability of the P. syringae pv. tomato DC3000 genome sequence has resulted in the identification of many novel effectors. We identified the hopPtoV effector gene on the basis of its location next to a candidate type III chaperone (TTC) gene, shcV, and within a pathogenicity island in the DC3000 chromosome. A DC3000 mutant lacking ShcV was unable to secrete detectable amounts …
Pseudomonas Syringae Type Iii Secretion System Targeting Signals And Novel Effectors Studied With A Cya Translocation Reporter, Lisa M. Schechter, Kathy A. Roberts, Yashitola Jamir, James R. Alfano, Alan Collmer
Pseudomonas Syringae Type Iii Secretion System Targeting Signals And Novel Effectors Studied With A Cya Translocation Reporter, Lisa M. Schechter, Kathy A. Roberts, Yashitola Jamir, James R. Alfano, Alan Collmer
Center for Plant Science Innovation: Faculty Publications
Pseudomonas syringae pv. tomato strain DC3000 is a pathogen of tomato and Arabidopsis. The hrp-hrcencoded type III secretion system (TTSS), which injects bacterial effector proteins (primarily called Hop or Avr proteins) into plant cells, is required for pathogenicity. In addition to being regulated by the HrpL alternative sigma factor, most avr or hop genes encode proteins with N termini that have several characteristic features, including (i) a high percentage of Ser residues, (ii) an aliphatic amino acid (Ile, Leu, or Val) or Pro at the third or fourth position, and (iii) a lack of negatively charged …
Activation Of A Coi1-Dependent Pathway In Arabidopsis By Pseudomonas Syringae Type Iii Effectors And Coronatine, Ping He, Satya Chintamanani, Zhongying Chen, Lihuang Zhu, Barbara N. Kunkel, James R. Alfano, Xiaoyan Tang, Jian-Min Zhou
Activation Of A Coi1-Dependent Pathway In Arabidopsis By Pseudomonas Syringae Type Iii Effectors And Coronatine, Ping He, Satya Chintamanani, Zhongying Chen, Lihuang Zhu, Barbara N. Kunkel, James R. Alfano, Xiaoyan Tang, Jian-Min Zhou
Center for Plant Science Innovation: Faculty Publications
Gram-negative bacteria use a variety of virulence factors including phytotoxins, exopolysaccharides, effectors secreted by the type III secretion system, and cell-wall-degrading enzymes to promote parasitism in plants. However, little is known about how these virulence factors alter plant celluar responses to promote disease. In this study, we show that virulent Pseudomonas syringae strains activate the transcription of an Arabidopsis ethylene response factor (ERF) gene, RAP2.6, in a coronatine insensitive 1 (COI1)-dependent manner. A highly sensitive RAP2.6 promoter-firely luciferase (RAP2.6-LUC) reporter line was developed to monitor activities of various bacterial virulence genes. Analyses of P. syringae pv. tomato DC3000 mutants indicated …
The Pseudomonas Syringae Type Iii-Secreted Protein Hopptod2 Possesses Protein Tyrosine Phosphatase Activity And Suppresses Programmed Cell Death In Plants, Avelina Espinosa, Ming Guo, Vincent C. Tam, Zheng Qing Fu, James R. Alfano
The Pseudomonas Syringae Type Iii-Secreted Protein Hopptod2 Possesses Protein Tyrosine Phosphatase Activity And Suppresses Programmed Cell Death In Plants, Avelina Espinosa, Ming Guo, Vincent C. Tam, Zheng Qing Fu, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
The bacterial plant pathogen Pseudomonas syringae possesses a type III protein secretion system that delivers many virulence proteins into plant cells. A subset of these proteins (called Avr proteins) is recognized by the plant’s innate immune system and triggers defences. One defence-associated response is the hypersensitive response (HR), a programmed cell death (PCD) of plant tissue. We have previously identified HopPtoD2 as a type III secreted protein from P. s. pv. tomato DC3000. Sequence analysis revealed that an N-terminal domain shared homology with Avr- PphD and a C-terminal domain was similar to protein tyrosine phosphatases (PTPs). We demonstrated that purified …
The Shca Protein Is A Molecular Chaperone That Assists In The Secretion Of The Hoppsya Effector From The Type Iii (Hrp) Protein Secretion System Of Pseudomonas Syringae, Karin V. Van Dijk, Vincent C. Tam, Angela R. Records, Tanja Petnicki-Ocwieja, James R. Alfano
The Shca Protein Is A Molecular Chaperone That Assists In The Secretion Of The Hoppsya Effector From The Type Iii (Hrp) Protein Secretion System Of Pseudomonas Syringae, Karin V. Van Dijk, Vincent C. Tam, Angela R. Records, Tanja Petnicki-Ocwieja, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
Pseudomonas syringae uses a type III protein secretion system encoded by the Hrp pathogenicity island (Pai) to translocate effector proteins into plant cells. One of these effector proteins is HopPsyA. A small open reading frame (ORF), named shcA, precedes the hopPsyA gene in the Hrp Pai of P. s. syringae 61. The predicted amino acid sequence of shcA shares general characteristics with chaperones used in type III protein secretion systems of animal pathogens. A functionally non-polar deletion of shcA in P. s. syringae 61 resulted in the loss of detectable HopPsyA in supernatant fractions, consistent with ShcA acting as a …
Genomewide Identification Of Pseudomonas Syringae Pv.Tomato Dc3000 Promoters Controlled By The Hrpl Alternative Sigma Factor, Derrick E. Fouts, Robert B. Abramovitch, James R. Alfano, Angela M. Baldo, C. Robin Buell, Samuel Cartinhour, Arn K. Chatterjee, Mark D'Ascenzo, Michelle L. Gwinn, Sondra G. Lazarowitz, Na-Chun Lin, Gregory B. Martin, Amos H. Rehm, David J. Schneider, Karin V. Van Dijk, Xiaoyan Tang, Alan Collmer
Genomewide Identification Of Pseudomonas Syringae Pv.Tomato Dc3000 Promoters Controlled By The Hrpl Alternative Sigma Factor, Derrick E. Fouts, Robert B. Abramovitch, James R. Alfano, Angela M. Baldo, C. Robin Buell, Samuel Cartinhour, Arn K. Chatterjee, Mark D'Ascenzo, Michelle L. Gwinn, Sondra G. Lazarowitz, Na-Chun Lin, Gregory B. Martin, Amos H. Rehm, David J. Schneider, Karin V. Van Dijk, Xiaoyan Tang, Alan Collmer
Center for Plant Science Innovation: Faculty Publications
The ability of Pseudomonas syringae pv. tomato DC3000 to parasitize tomato and Arabidopsis thaliana depends on genes activated by the HrpL alternative sigma factor. To support various functional genomic analyses of DC3000, and specifically, to identify genes involved in pathogenesis, we developed a draft sequence of DC3000 and used an iterative process involving computational and gene expression techniques to identify virulence-implicated genes downstream of HrpLresponsive promoters. Hypersensitive response and pathogenicity (Hrp) promoters are known to control genes encoding the Hrp (type III protein secretion) machinery and a few type III effector proteins in DC3000. This process involved (i) identification of …
Pseudomonas Syringae Hrp Type Iii Secretion System And Effector Proteins, Alan Collmer, Jorge L. Badel, Amy O. Charkowski, Wen-Ling Deng, Derrick E. Fouts, Adela R. Ramos, Amos H. Rehm, Deborah M. Anderson, Olaf Schneewind, Karin V. Van Dijk, James R. Alfano
Pseudomonas Syringae Hrp Type Iii Secretion System And Effector Proteins, Alan Collmer, Jorge L. Badel, Amy O. Charkowski, Wen-Ling Deng, Derrick E. Fouts, Adela R. Ramos, Amos H. Rehm, Deborah M. Anderson, Olaf Schneewind, Karin V. Van Dijk, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
Pseudomonas syringae is a member of an important group of Gram-negative bacterial pathogens of plants and animals that depend on a type III secretion system to inject virulence effector proteins into host cells. In P. syringae, hrpyhrc genes encode the Hrp (type III secretion) system, and avirulence (avr) and Hrpdependent outer protein (hop) genes encode effector proteins. The hrpyhrc genes of P. syringae pv syringae 61, P. syringae pv syringae B728a, and P. syringae pv tomato DC3000 are flanked by an exchangeable effector locus and …
The Pseudomonas Syringae Hrp Pathogenicity Island Has A Tripartite Mosaic Structure Composed Of A Cluster Of Type Iii Secretion Genes Bounded By Exchangeable Effector And Conserved Effector Loci That Contribute To Parasitic Fitness And Pathogenicity In Plants, James R. Alfano, Amy O. Charkowski, Wen-Ling Deng, Jorge L. Badel, Tanja Petnicki- Ocwieja, Karin Van Dijk, Alan Collmer
The Pseudomonas Syringae Hrp Pathogenicity Island Has A Tripartite Mosaic Structure Composed Of A Cluster Of Type Iii Secretion Genes Bounded By Exchangeable Effector And Conserved Effector Loci That Contribute To Parasitic Fitness And Pathogenicity In Plants, James R. Alfano, Amy O. Charkowski, Wen-Ling Deng, Jorge L. Badel, Tanja Petnicki- Ocwieja, Karin Van Dijk, Alan Collmer
Center for Plant Science Innovation: Faculty Publications
The plant pathogenic bacterium Pseudomonas syringae is divided into pathovars differing in host specificity, with P. syringae pv. syringae (Psy) and P. syringae pv. tomato (Pto) representing particularly divergent pathovars. P. syringae hrp/hrc genes encode a type III protein secretion system that appears to translocate Avr and Hop effector proteins into plant cells. DNA sequence analysis of the hrp/hrc regions in Psy 61, Psy B728a, and Pto DC3000 has revealed a Hrp pathogenicity island (Pai) with a tripartite mosaic structure. The hrp/hrc gene cluster is conserved in all three strains and is flanked by a unique exchangeable …
The Avr (Effector) Proteins Hrma (Hoppsya) And Avrpto Are Secreted In Culture From Pseudomonas Syringae Pathovars Via The Hrp (Type Iii) Protein Secretion System In A Temperature- And Ph-Sensitive Manner, Karin V. Van Dijk, Derrick E. Fouts, Amos H. Rehm, Angela R. Hill, Alan Collmer, James R. Alfano
The Avr (Effector) Proteins Hrma (Hoppsya) And Avrpto Are Secreted In Culture From Pseudomonas Syringae Pathovars Via The Hrp (Type Iii) Protein Secretion System In A Temperature- And Ph-Sensitive Manner, Karin V. Van Dijk, Derrick E. Fouts, Amos H. Rehm, Angela R. Hill, Alan Collmer, James R. Alfano
Center for Plant Science Innovation: Faculty Publications
We present here data showing that the Avr proteins HrmA and AvrPto are secreted in culture via the native Hrp pathways from Pseudomonas syringae pathovars that produce these proteins. Moreover, their secretion is strongly affected by the temperature and pH of the culture medium. Both HrmA and AvrPto were secreted at their highest amounts when the temperature was between 18 and 22°C and when the culture medium was pH 6.0. In contrast, temperature did not affect the secretion of HrpZ. pH did affect HrpZ secretion, but not as strongly as it affected the secretion of HrmA. This finding suggests that …
The Pseudomonas Syringae Pv. Tomato Hrpw Protein Has Domains Similar To Harpins And Pectate Lyases And Can Elicit The Plant Hypersensitive Response And Bind To Pectate, Amy O. Charkowski, James R. Alfano, Gail Preston, Jing Yuan, Sheng Yang He, Alan Collmer
The Pseudomonas Syringae Pv. Tomato Hrpw Protein Has Domains Similar To Harpins And Pectate Lyases And Can Elicit The Plant Hypersensitive Response And Bind To Pectate, Amy O. Charkowski, James R. Alfano, Gail Preston, Jing Yuan, Sheng Yang He, Alan Collmer
Center for Plant Science Innovation: Faculty Publications
The host-specific plant pathogen Pseudomonas syringae elicits the hypersensitive response (HR) in nonhost plants and secretes the HrpZ harpin in culture via the Hrp (type III) secretion system. Previous genetic evidence suggested the existence of another harpin gene in the P. syringae genome. hrpW was found in a region adjacent to the hrp cluster in P. syringae pv. tomato DC3000. hrpW encodes a 42.9-kDa protein with domains resembling harpins and pectate lyases (Pels), respectively. HrpW has key properties of harpins. It is heat stable and glycine rich, lacks cysteine, is secreted by the Hrp system, and is able to elicit …