scholarly journals Tal2c Activates the Expression of OsF3H04g to Promote Infection as a Redundant TALE of Tal2b in Xanthomonas oryzae pv. oryzicola

2021 ◽  
Vol 22 (24) ◽  
pp. 13628
Author(s):  
Tao Wu ◽  
Haimiao Zhang ◽  
Yunya Bi ◽  
Yue Yu ◽  
Haifeng Liu ◽  
...  
Keyword(s):  
Virulent Strain ◽  
Xanthomonas Oryzae ◽  
Transcription Activator ◽  
Altered Expression ◽  
Overexpression Line ◽  
Dioxygenase Gene ◽  
Highly Virulent ◽  
Effector Binding ◽  
Host Genes ◽  
Increased Susceptibility

Xanthomonas oryzae delivers transcription activator-like effectors (TALEs) into plant cells to facilitate infection. Following economic principles, the redundant TALEs are rarely identified in Xanthomonas. Previously, we identified the Tal2b, which activates the expression of the rice 2-oxoglutarate-dependent dioxygenase gene OsF3H03g to promote infection in the highly virulent strain of X. oryzae pv. oryzicola HGA4. Here, we reveal that another clustered TALE, Tal2c, also functioned as a virulence factor to target rice OsF3H04g, a homologue of OsF3H03g. Transferring Tal2c into RS105 induced expression of OsF3H04g to coincide with increased susceptibility in rice. Overexpressing OsF3H04g caused higher susceptibility and less salicylic acid (SA) production compared to wild-type plants. Moreover, CRISPR–Cas9 system-mediated editing of the effector-binding element in the promoters of OsF3H03g or OsF3H04g was found to specifically enhance resistance to Tal2b- or Tal2c-transferring strains, but had no effect on resistance to either RS105 or HGA4. Furthermore, transcriptome analysis revealed that several reported SA-related and defense-related genes commonly altered expression in OsF3H04g overexpression line compared with those identified in OsF3H03g overexpression line. Overall, our results reveal a functional redundancy mechanism of pathogenic virulence in Xoc in which tandem Tal2b and Tal2c specifically target homologues of host genes to interfere with rice immunity by reducing SA.

scholarly journals Identification of virulence tal gene in the cotton pathogen, Xanthomonas citri pv. malvacearum strain Xss-V2-18

2020 ◽  
Author(s):  
Fazal Haq ◽  
Syed Mashab Ali Shah ◽  
Shiwang Xie ◽  
Kunxuan Huang ◽  
Wenxiu Ma ◽  
...  
Keyword(s):  
Virulent Strain ◽  
Evolutionary Relationship ◽  
The United States ◽  
In Planta ◽  
Dna Encoding ◽  
Transcription Activator ◽  
Xanthomonas Citri ◽  
Suicide Vector ◽  
In Trans ◽  
Highly Virulent

Abstract Background Bacterial blight of cotton (BBC), which is incited by Xanthomonas citri pv. malvacearum ( Xcm ), is a destructive disease in cotton. Transcription activator-like effectors (TALEs), encoded by tal -genes, play critical roles in the pathogenesis of xanthomonads. Characterized strains of cotton pathogenic Xcm harbor 6-13 different tal genes and only one of them is functionally decoded. Further identification of novel tal genes in Xcm strains with virulence contributions are prerequisite to decipher the Xcm -cotton interactionsResults In this study, we identified six tal genes in Xss-V 2 -18, a highly-virulent strain of Xcm from China, and assessed their role in BBC. RFLP-based Southern hybridization assays indicated that Xss-V 2 -18 harbors the six tal genes on a plasmid. The plasmid-encoded tal genes were isolated by cloning Bam HI fragments and screening clones by colony hybridization. The tal genes were sequenced by inserting a Tn 5 transposon in the DNA encoding the central repeat region (CRR) of each tal gene. Xcm TALome evolutionary relationship based on TALEs CRR revealed relatedness of Xss-V 2 -18 to MSCT1 and MS14003 from the United States. However, Tal2 of Xss-V 2 -18 differs at two repeat variable diresidues (RVDs) from Tal6 and Tal26 in MSCT1 and MS14003, respectively, inferred functional dissimilarity. The suicide vector pKMS1 was then used to construct tal deletion mutants in Xcm Xss-V 2 -18. The mutants were evaluated for pathogenicity in cotton based on symptomology and growth in planta . Four mutants showed attenuated virulence and all contained mutations in tal2 . One tal2 mutant designated M2 was further investigated in complementation assays. When tal2 was introduced into Xcm M2 and expressed in trans , the mutant was complemented for both symptoms and growth in planta , thus indicating that tal2 functions as a virulence factor in Xcm Xss-V 2 -18.Conclusions Overall, the results demonstrated that Tal2 is a major pathogenicity factor in Xcm strain Xss-V 2 -18 that contributes significantly in BBC. This study provides a foundation for future efforts aimed at identifying susceptibility genes in cotton that are targeted by Tal2.

scholarly journals Two nuclear effectors of the rice blast fungus modulate host immunity via transcriptional reprogramming

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Seongbeom Kim ◽  
Chi-Yeol Kim ◽  
Sook-Young Park ◽  
Ki-Tae Kim ◽  
Jongbum Jeon ◽  
...  
Keyword(s):  
Rice Blast ◽  
Fungal Pathogens ◽  
Plant Immunity ◽  
Xanthomonas Oryzae ◽  
Necrotrophic Pathogen ◽  
Transcriptional Reprogramming ◽  
Enhanced Resistance ◽  
Effector Binding ◽  
Biotrophic Interfacial Complex ◽  
Increased Susceptibility

AbstractPathogens utilize multiple types of effectors to modulate plant immunity. Although many apoplastic and cytoplasmic effectors have been reported, nuclear effectors have not been well characterized in fungal pathogens. Here, we characterize two nuclear effectors of the rice blast pathogen Magnaporthe oryzae. Both nuclear effectors are secreted via the biotrophic interfacial complex, translocated into the nuclei of initially penetrated and surrounding cells, and reprogram the expression of immunity-associated genes by binding on effector binding elements in rice. Their expression in transgenic rice causes ambivalent immunity: increased susceptibility to M. oryzae and Xanthomonas oryzae pv. oryzae, hemibiotrophic pathogens, but enhanced resistance to Cochliobolus miyabeanus, a necrotrophic pathogen. Our findings help remedy a significant knowledge deficiency in the mechanism of M. oryzae–rice interactions and underscore how effector-mediated manipulation of plant immunity by one pathogen may also affect the disease severity by other pathogens.

Protective effect of Trypanosoma rangeli against infections with a highly virulent strain of Trypanosoma cruzi

1997 ◽  
Vol 2 (5) ◽  
pp. 482-487 ◽  
Author(s):  
Claudio Zuniga ◽  
Teresa Palau ◽  
Pilar Penin ◽  
Carlos Gamallo ◽  
Jose Antonio de Diego
Keyword(s):  
Trypanosoma Cruzi ◽  
Protective Effect ◽  
Virulent Strain ◽  
Trypanosoma Rangeli ◽  
Highly Virulent

scholarly journals Efficacy of a Vaccine Based on Protective Antigen and Killed Spores against Experimental Inhalational Anthrax

2008 ◽  
Vol 77 (3) ◽  
pp. 1197-1207 ◽  
Author(s):  
Yves P. Gauthier ◽  
Jean-Nicolas Tournier ◽  
Jean-Charles Paucod ◽  
Jean-Philippe Corre ◽  
Michèle Mock ◽  
...  
Keyword(s):  
Guinea Pigs ◽  
Protective Immunity ◽  
Protective Antigen ◽  
Virulent Strain ◽  
Neutralizing Antibody ◽  
Cutaneous Anthrax ◽  
Anthrax Vaccines ◽  
Mucosal Secretions ◽  
Highly Virulent ◽  
Lethal Doses

ABSTRACTProtective antigen (PA)-based anthrax vaccines acting on toxins are less effective than live attenuated vaccines, suggesting that additional antigens may contribute to protective immunity. Several reports indicate that capsule or spore-associated antigens may enhance the protection afforded by PA. Addition of formaldehyde-inactivated spores (FIS) to PA (PA-FIS) elicits total protection against cutaneous anthrax. Nevertheless, vaccines that are effective against cutaneous anthrax may not be so against inhalational anthrax. The aim of this work was to optimize immunization with PA-FIS and to assess vaccine efficacy against inhalational anthrax. We assessed the immune response to recombinant anthrax PA fromBacillus anthracis(rPA)-FIS administered by various immunization protocols and the protection provided to mice and guinea pigs infected through the respiratory route with spores of a virulent strain ofB. anthracis. Combined subcutaneous plus intranasal immunization of mice yielded a mucosal immunoglobulin G response to rPA that was more than 20 times higher than that in lung mucosal secretions after subcutaneous vaccination. The titers of toxin-neutralizing antibody and antispore antibody were also significantly higher: nine and eight times higher, respectively. The optimized immunization elicited total protection of mice intranasally infected with the virulentB. anthracisstrain 17JB. Guinea pigs were fully protected, both against an intranasal challenge with 100 50% lethal doses (LD50) and against an aerosol with 75 LD50of spores of the highly virulent strain 9602. Conversely, immunization with PA alone did not elicit protection. These results demonstrate that the association of PA and spores is very much more effective than PA alone against experimental inhalational anthrax.

scholarly journals Cytokine expression in the liver of mice infected with a highly virulent strain ofFrancisella tularensis

1996 ◽  
Vol 13 (3) ◽  
pp. 239-244 ◽  
Author(s):  
Igor Golovliov ◽  
Kerstin Kuoppa ◽  
Anders Sjöstedt ◽  
Arne Tärnvik ◽  
Gunnar Sandström
Keyword(s):  
Virulent Strain ◽  
Cytokine Expression ◽  
Highly Virulent

scholarly journals Analysis of Virus Population Profiles within Pigs Infected with Virulent Classical Swine Fever Viruses: Evidence for Bottlenecks in Transmission but Absence of Tissue-Specific Virus Variants

2020 ◽  
Vol 94 (19) ◽  
Author(s):  
Camille Melissa Johnston ◽  
Ulrik Fahnøe ◽  
Louise Lohse ◽  
Jens Bukh ◽  
Graham J. Belsham ◽  
...  
Keyword(s):  
Classical Swine Fever Virus ◽  
Population Change ◽  
Virulent Strain ◽  
Severe Disease ◽  
Clinical Signs ◽  
Classical Swine Fever ◽  
Fever Virus ◽  
Host Cells ◽  
Virus Population ◽  
Highly Virulent

ABSTRACT Classical swine fever virus (CSFV) contains a specific motif within the E2 glycoprotein that differs between strains of different virulence. In the highly virulent CSFV strain Koslov, this motif comprises residues S763/L764 in the polyprotein. However, L763/P764 represent the predominant alleles in published CSFV genomes. In this study, changes were introduced into the CSFV strain Koslov (here called vKos_SL) to generate modified CSFVs with substitutions at residues 763 and/or 764 (vKos_LL, vKos_SP, and vKos_LP). The properties of these mutant viruses, in comparison to those of vKos_SL, were determined in pigs. Each of the viruses was virulent and induced typical clinical signs of CSF, but the vKos_LP strain produced them significantly earlier. Full-length CSFV cDNA amplicons (12.3 kb) derived from sera of infected pigs were deep sequenced and cloned to reveal the individual haplotypes that contributed to the single-nucleotide polymorphism (SNP) profiles observed in the virus population. The SNP profiles for vKos_SL and vKos_LL displayed low-level heterogeneity across the entire genome, whereas vKos_SP and vKos_LP displayed limited diversity with a few high-frequency SNPs. This indicated that vKos_SL and vKos_LL exhibited a higher level of fitness in the host and more stability at the consensus level, whereas several consensus changes were observed in the vKos_SP and vKos_LP sequences, pointing to adaptation. For each virus, only a subset of the variants present within the virus inoculums were maintained in the infected pigs. No clear tissue-dependent quasispecies differentiation occurred within inoculated pigs; however, clear evidence for transmission bottlenecks to contact animals was observed, with subsequent loss of sequence diversity. IMPORTANCE The surface-exposed E2 protein of classical swine fever virus is required for its interaction with host cells. A short motif within this protein varies between strains of different virulence. The importance of two particular amino acid residues in determining the properties of a highly virulent strain of the virus has been analyzed. Each of the different viruses tested proved highly virulent, but one of them produced earlier, but not more severe, disease. By analyzing the virus genomes present within infected pigs, it was found that the viruses which replicated within inoculated animals were only a subset of those within the virus inoculum. Furthermore, following contact transmission, it was shown that a very restricted set of viruses had transferred between animals. There were no significant differences in the virus populations present in various tissues of the infected animals. These results indicate mechanisms of virus population change during transmission between animals.

scholarly journals STUDIES ON IMMUNITY TO PNEUMOCOCCUS MUCOSUS (TYPE III)

1927 ◽  
Vol 45 (6) ◽  
pp. 1093-1106 ◽  
Author(s):  
William S. Tillett
Keyword(s):  
Biological Property ◽  
Infected Animal ◽  
Virulent Strain ◽  
The Other ◽  
Natural Resistance ◽  
Type Iii ◽  
Mechanism Of Resistance ◽  
Initial Decrease ◽  
High Degree ◽  
Highly Virulent

The observations recorded in this paper on the infectivity of Type III pneumococci for rabbits may be summarized as follows: 1. Of eleven strains of Type III isolated from human sources, ten were found to possess low virulence for rabbits. This was true despite the fact that all the strains tested possessed large capsules and a high degree of virulence for mice. 2. One strain of Type III pneumococcus was rendered highly virulent for rabbits. Since it possessed no other biological property demonstrably different from the other strains, its virulence must reside in some additional property. 3. An initial decrease in the number of circulating organisms following the injection of virulent bacteria is a well known occurrence, and it was observed in rabbits injected with the rabbit virulent strain of Type III. However, the extent of the reduction was in inverse proportion to the degree of virulence of the strain; a fact which makes mechanical explanations of the phenomenon insufficient. 4. The bacteremia produced in rabbits by Type III pneumococci, avirulent for this species, runs a characteristic course. It differs from that produced by non-encapsulated R forms of pneumococci although in both instances survival of the infected animal ensues. This is evidence that the mechanism of resistance against encapsulated and non-encapsulated pneumococci is not identical. 5. Phagocytosis of Type III pneumococci by circulating rabbit leucocytes was not demonstrable by a vital stain technique, whereas under the same conditions the ingestion of non-encapsulated R forms occurred. This is further evidence that the process whereby non-encapsulated pneumococci are disposed of, is insufficient to explain the natural resistance of rabbits to infection with encapsulated Type III pneumococci.

scholarly journals Gut–Liver Immune Response and Gut Microbiota Profiling Reveal the Pathogenic Mechanisms of Vibrio harveyi in Pearl Gentian Grouper (Epinephelus lanceolatus♂ × E. fuscoguttatus♀)

2020 ◽  
Vol 11 ◽  
Author(s):  
Yiqin Deng ◽  
Yaqiu Zhang ◽  
Haoxiang Chen ◽  
Liwen Xu ◽  
Qian Wang ◽  
...  
Keyword(s):  
Immune Response ◽  
Bacterial Community ◽  
Gut Microbiota ◽  
Vibrio Harveyi ◽  
Virulent Strain ◽  
Interspecies Interactions ◽  
Genes Encoding ◽  
Genetic Information Processing ◽  
Cellular Immune ◽  
Highly Virulent

Vibrio harveyi causes vibriosis in nearly 70% of grouper (Epinephelus sp.), seriously limiting grouper culture. As well as directly inhibiting pathogens, the gut microbiota plays critical roles in immune homeostasis and provides essential health benefits to its host. However, there is still little information about the variations in the immune response to V. harveyi infection and the gut microbiota of grouper. To understand the virulence mechanism of V. harveyi in the pearl gentian grouper, we investigated the variations in the pathological changes, immune responses, and gut bacterial communities of pearl gentian grouper after exposure to differently virulent V. harveyi strains. Obvious histopathological changes were detected in heart, kidney, and liver. In particular, nodules appeared and huge numbers of V. harveyi cells colonized the liver at 12 h postinfection (hpi) with highly virulent V. harveyi. Although no V. harveyi was detected in the gut, the infection simultaneously induced a gut-liver immune response. In particular, the expression of 8 genes associated with cellular immune processes, including genes encoding inflammatory cytokines and receptors, and pattern recognition proteins, was markedly induced by V. harveyi infection, especially with the highly virulent V. harveyi strain. V. harveyi infection also induced significant changes in gut bacterial community, in which Vibrio and Photobacterium increased but Bradyrhizobium, Lactobacillus, Blautia, and Faecalibaculum decreased in the group infected with the highly virulent strain, with accounting for 82.01% dissimilarity. Correspondingly, four bacterial functions related to bacterial pathogenesis were increased by infection with highly virulent V. harveyi, whereas functions involving metabolism and genetic information processing were reduced. These findings indicate that V. harveyi colonizes the liver and induces a gut-liver immune response that substantially disrupts the composition of and interspecies interactions in the bacterial community in fish gut, thereby altering the gut-microbiota-mediated functions and inducing fish death.

scholarly journals Draft Genome Sequence of a Rare Israeli Clinical Isolate of Burkholderia pseudomallei

2019 ◽  
Vol 8 (19) ◽  
Author(s):  
Ofir Israeli ◽  
Inbar Cohen-Gihon ◽  
Tal Brosh-Nissimov ◽  
Shay Weiss ◽  
Anat Zvi ◽  
...  
Keyword(s):  
Clinical Isolate ◽  
Genome Sequence ◽  
Burkholderia Pseudomallei ◽  
Virulent Strain ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Content Type ◽  
Highly Virulent

We report here the draft genome sequence of Burkholderia pseudomallei MAA2018. This highly virulent strain was isolated in 2018 from the first melioidosis case in Israel associated with recreational travel to Goa, India.

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