Organization, regulation and function of Pseudomonas syringae pv. syringae hrp genes

1994 ◽  
pp. 593-603 ◽  
Author(s):  
Steven W. Hutcheson ◽  
Sunggi Heu ◽  
Hsiou-Chen Huang ◽  
Michael C. Lidell ◽  
Yingxian Xiao
Keyword(s):  
Pseudomonas Syringae ◽  
Hrp Genes ◽  
And Function

scholarly journals Pseudomonas syringae Phytotoxins: Mode of Action, Regulation, and Biosynthesis by Peptide and Polyketide Synthetases

1999 ◽  
Vol 63 (2) ◽  
pp. 266-292 ◽  
Author(s):  
Carol L. Bender ◽  
Francisco Alarcón-Chaidez ◽  
Dennis C. Gross
Keyword(s):  
Pseudomonas Syringae ◽  
Plasma Membranes ◽  
Antimicrobial Agents ◽  
Gene Clusters ◽  
Regulatory Genes ◽  
Signal Molecules ◽  
Peptide Synthetases ◽  
Biological Stress ◽  
Regulatory Circuits ◽  
And Function

SUMMARY Coronatine, syringomycin, syringopeptin, tabtoxin, and phaseolotoxin are the most intensively studied phytotoxins of Pseudomonas syringae, and each contributes significantly to bacterial virulence in plants. Coronatine functions partly as a mimic of methyl jasmonate, a hormone synthesized by plants undergoing biological stress. Syringomycin and syringopeptin form pores in plasma membranes, a process that leads to electrolyte leakage. Tabtoxin and phaseolotoxin are strongly antimicrobial and function by inhibiting glutamine synthetase and ornithine carbamoyltransferase, respectively. Genetic analysis has revealed the mechanisms responsible for toxin biosynthesis. Coronatine biosynthesis requires the cooperation of polyketide and peptide synthetases for the assembly of the coronafacic and coronamic acid moieties, respectively. Tabtoxin is derived from the lysine biosynthetic pathway, whereas syringomycin, syringopeptin, and phaseolotoxin biosynthesis requires peptide synthetases. Activation of phytotoxin synthesis is controlled by diverse environmental factors including plant signal molecules and temperature. Genes involved in the regulation of phytotoxin synthesis have been located within the coronatine and syringomycin gene clusters; however, additional regulatory genes are required for the synthesis of these and other phytotoxins. Global regulatory genes such as gacS modulate phytotoxin production in certain pathovars, indicating the complexity of the regulatory circuits controlling phytotoxin synthesis. The coronatine and syringomycin gene clusters have been intensively characterized and show potential for constructing modified polyketides and peptides. Genetic reprogramming of peptide and polyketide synthetases has been successful, and portions of the coronatine and syringomycin gene clusters could be valuable resources in developing new antimicrobial agents.

scholarly journals A 2′-O-Methyltransferase Responsible for Transfer RNA Anticodon Modification Is Pivotal for Resistance to Pseudomonas syringae DC3000 in Arabidopsis

2018 ◽  
Vol 31 (12) ◽  
pp. 1323-1336 ◽  
Author(s):  
Vicente Ramírez ◽  
Beatriz González ◽  
Ana López ◽  
Maria Jose Castelló ◽  
Maria José Gil ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Transfer Rna ◽  
Resistance Response ◽  
Chemical Structures ◽  
Trna Modifications ◽  
Trna Species ◽  
Living Organisms ◽  
And Function

Transfer RNA (tRNA) is the most highly modified class of RNA species in all living organisms. Recent discoveries have revealed unprecedented complexity in the tRNA chemical structures, modification patterns, regulation, and function, suggesting that each modified nucleoside in tRNA may have its own specific function. However, in plants, our knowledge of the role of individual tRNA modifications and how they are regulated is very limited. In a genetic screen designed to identify factors regulating disease resistance in Arabidopsis, we identified SUPPRESSOR OF CSB3 9 (SCS9). Our results reveal SCS9 encodes a tRNA methyltransferase that mediates the 2′-O-ribose methylation of selected tRNA species in the anticodon loop. These SCS9-mediated tRNA modifications enhance susceptibility during infection with the virulent bacterial pathogen Pseudomonas syringae DC3000. Lack of such tRNA modification, as observed in scs9 mutants, specifically dampens plant resistance against DC3000 without compromising the activation of the salicylic acid signaling pathway or the resistance to other biotrophic pathogens. Our results support a model that gives importance to the control of certain tRNA modifications for mounting an effective disease resistance in Arabidopsis toward DC3000 and, therefore, expands the repertoire of molecular components essential for an efficient disease resistance response.

scholarly journals Immunogold Labeling of Hrp Pili of Pseudomonas syringae pv. tomato Assembled in Minimal Medium and In Planta

2001 ◽  
Vol 14 (2) ◽  
pp. 234-241 ◽  
Author(s):  
Wenqi Hu ◽  
Jing Yuan ◽  
Qiao-Ling Jin ◽  
Patrick Hart ◽  
Sheng Yang He
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Syringae ◽  
Minimal Medium ◽  
Leaf Tissue ◽  
Hypersensitive Reaction ◽  
Immunogold Labeling ◽  
Structural Protein ◽  
In Planta ◽  
Hrp Genes

Hypersensitive reaction and pathogenicity (hrp) genes are required for Pseudomonas syringae pv. tomato (Pst) DC3000 to cause disease in susceptible tomato and Arabidopsis thaliana plants and to elicit the hypersensitive response in resistant plants. The hrp genes encode a type III protein secretion system known as the Hrp system, which in Pst DC3000 secretes HrpA, HrpZ, HrpW, and AvrPto and assembles a surface appendage, named the Hrp pilus, in hrp-gene-inducing minimal medium. HrpA has been suggested to be the Hrp pilus structural protein on the basis of copurification and mutational analyses. In this study, we show that an antibody against HrpA efficiently labeled Hrp pili, whereas antibodies against HrpW and HrpZ did not. Immunogold labeling of bacteria-infected Arabidopsis thaliana leaf tissue with an Hrp pilus antibody revealed a characteristic lineup of gold particles around bacteria and/or at the bacterium-plant contact site. These results confirm that HrpA is the major structural protein of the Hrp pilus and provide evidence that Hrp pili are assembled in vitro and in planta.

scholarly journals Evidence for a Novel Phylotype of Pseudomonas syringae Causing Bacterial Leaf Blight of Cantaloupe in China

Plant Disease ◽  
2017 ◽  
Vol 101 (10) ◽  
pp. 1746-1752
Author(s):  
Yanli Tian ◽  
Yuqiang Zhao ◽  
Xuezi Chen ◽  
Yuanfeng Dai ◽  
Wenjun Zhao ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Housekeeping Genes ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Negative Results ◽  
Specific Pcr ◽  
Hrp Genes ◽  
Pathogenicity Tests ◽  
Cucumis Melo L ◽  
Reference Strains

Bacterial leaf blight (BLB) has caused severe yield losses in cantaloupe (Cucumis melo L.) in the major melon-growing regions of China since the beginning of the twentieth century. Historically, Pseudomonas syringae pv. lachrymans was considered to be the causal agent of BLB of cantaloupe and angular leaf spot of cucumber. In the process of characterizing bacteria isolated from cantaloupe, we observed that putative P. syringae pv. lachrymans yielded negative results in P. syringae pv. lachrymans-specific PCR assays. This suggested that the P. syringae pv. lachrymans-like strains from cantaloupe were distinct from those recovered from cucumber. To investigate the differences between P. syringae pv. lachrymans-like strains isolated from cantaloupe and cucumber, 13 P. syringae strains isolated from cantaloupe [12 from China and 1 from Zimbabwe (NCPPB2916)] and 7 additional P. syringae reference strains were analyzed by catabolic profiling, phylogenetic analysis by multilocus sequence analysis (MLSA) and pathogenicity tests on cantaloupe leaflets. Catabolic profiling and MLSA based on 10 housekeeping genes and 2 hypersensitive response and pathogenicity (hrp) genes allowed us to differentiate strains isolated from cantaloupe and cucumber. Pseudomonas syringae pv. lachrymans strains isolated from cucumber clustered with genomospecies 2, and 13 P. syringae strains isolated from cantaloupe belonged to genomospecies 1. While all cantaloupe strains were closely related to P. syringae pv. aptata, they could be differentiated from this pathovar based on metabolic tests and MLSA. Pathogenicity tests showed that all strains isolated from cantaloupe and cucumber were only pathogenic on their original hosts. Based on these observations we conclude that P. syringae pv. lachrymans strains recovered from cantaloupe in China represent a novel phylotype.

scholarly journals The Presence of hrp Genes on the Pathogenicity-Associated Plasmid of the Tumorigenic Bacterium Erwinia herbicola pv. gypsophilae

1997 ◽  
Vol 10 (5) ◽  
pp. 677-682 ◽  
Author(s):  
Roni Nizan ◽  
Isaac Barash ◽  
Lea Valinsky ◽  
Amnon Lichter ◽  
Shulamit Manulis
Keyword(s):  
Gene Cluster ◽  
Pseudomonas Syringae ◽  
Hypersensitive Reaction ◽  
Amino Acid Sequences ◽  
Open Reading Frames ◽  
Cytokinin Biosynthesis ◽  
Erwinia Herbicola ◽  
Hrp Genes ◽  
Genes Encoding ◽  
Bacterial Genes

The pathogenicity-associated plasmid (pPATH) of Erwinia herbicola pv. gypsophilae (Ehg), which is present only in pathogenic strains, contains a gene cluster encoding indole-3-acetic acid and cytokinin biosynthesis. The transposon-reporter Tn3-Spice was used to generate nonpathogenic mutants on two overlapping cosmids, pLA150 and pLA352, of the pPATH. A cluster of such mutations, which spanned 16 kb, mapped approximately 15 kb from the gene cluster involved in phytohormone biosynthesis. Non-pathogenic mutants also failed to elicit the hypersensitive reaction (HR) on tobacco. Pathogenicity and HR were restored concomitantly to these mutants by in trans complementation with wild-type Ehg DNA. A 3.8-kb HindIII DNA fragment that complemented the hrp mutants was sequenced and six complete and two partial open reading frames (ORFs) were identified. Comparison of the deduced amino acid sequences of the eight ORFs showed striking homology and co-linearity with hrp genes of E. amylovora as well as with other plant and mammalian pathogenic bacterial genes encoding proteins of the type III secretion system. Limited DNA sequencing at various sites on the remaining 11-kb region of pLA352 also showed high identity to Hrp proteins of E. amylovora, E. stewartii, and Pseudomonas syringae. These results suggest that hrp genes are mandatory for gall formation by E. herbicola pv. gypsophilae.

scholarly journals Biochemical Characterization and Function of Eight Microbial Type Terpene Synthases from Lycophyte Selaginella moellendorffii

2021 ◽  
Vol 22 (2) ◽  
pp. 605
Author(s):  
Yapei Zhao ◽  
Tian Hu ◽  
Ruiqi Liu ◽  
Zhiqiang Hao ◽  
Guoyan Liang ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Biochemical Characterization ◽  
Vascular Plant ◽  
Terpene Synthase ◽  
Tomato Dc3000 ◽  
Terpene Synthases ◽  
Geranyl Diphosphate ◽  
And Function ◽  
Selaginella Moellendorffii ◽  
And Staphylococcus Aureus

Selaginella moellendorffii is a lycophyte, a member of an ancient vascular plant lineage. Two distinct types of terpene synthase (TPS) genes were identified from this species, including S. moellendorffii TPS genes (SmTPSs) and S. moellendorffii microbial TPS-like genes (SmMTPSLs). The goal of this study was to investigate the biochemical functions of SmMTPSLs. Here, eight full-length SmMTPSL genes (SmMTPSL5, -15, -19, -23, -33, -37, -46, and -47) were functionally characterized from S. moellendorffii. Escherichia coli-expressed recombinant SmMTPSLs were tested for monoterpenes synthase and sesquiterpenes synthase activities. These enzymatic products were typical monoterpenes and sesquiterpenes that have been previous shown to be generated by typical plant TPSs when provided with geranyl diphosphate (GPP) and farnesyl diphosphate (FPP) as the substrates. Meanwhile, SmMTPSL23, -33, and -37 were up-regulated when induced by alamethicin (ALA) and methyl jasmonate (MeJA), suggesting a role for these genes in plants response to abiotic stresses. Furthermore, this study pointed out that the terpenoids products of SmMTPSL23, -33, and -37 have an antibacterial effect on Pseudomonas syringae pv. tomato DC3000 and Staphylococcus aureus. Taken together, these results provide more information about the catalytic and biochemical function of SmMTPSLs in S. moellendorffii plants.

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