The needle and the damage done: type III effectors and the plant immune response.

AbstractCharacteristic properties of type III CRISPR-Cas systems include recognition of target RNA and the subsequent induction of a multifaceted immune response. This involves sequence-specific cleavage of the target RNA and production of cyclic oligoadenylate (cOA) molecules. Here we report that an exposed seed region at the 3′ end of the crRNA is essential for target RNA binding and cleavage, whereas cOA production requires base pairing at the 5′ end of the crRNA. Moreover, we uncover that the variation in the size and composition of type III complexes within a single host results in variable seed regions. This may prevent escape by invading genetic elements, while controlling cOA production tightly to prevent unnecessary damage to the host. Lastly, we use these findings to develop a new diagnostic tool, SCOPE, for the specific detection of SARS-CoV-2 from human nasal swab samples, revealing sensitivities in the atto-molar range.

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Identification of type III effectors modulating the symbiotic properties of Bradyrhizobium vignae strain ORS3257 with various Vigna species

Scientific Reports ◽

10.1038/s41598-021-84205-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Pongpan Songwattana ◽

Clémence Chaintreuil ◽

Jenjira Wongdee ◽

Albin Teulet ◽

Mamadou Mbaye ◽

...

Keyword(s):

Positive Impact ◽

Symbiotic Efficiency ◽

Type Iii Effectors ◽

Type Iii ◽

Vigna Species ◽

Symbiotic Properties

AbstractThe Bradyrhizobium vignae strain ORS3257 is an elite strain recommended for cowpea inoculation in Senegal. This strain was recently shown to establish symbioses on some Aeschynomene species using a cocktail of Type III effectors (T3Es) secreted by the T3SS machinery. In this study, using a collection of mutants in different T3Es genes, we sought to identify the effectors that modulate the symbiotic properties of ORS3257 in three Vigna species (V. unguiculata, V. radiata and V. mungo). While the T3SS had a positive impact on the symbiotic efficiency of the strain in V. unguiculata and V. mungo, it blocked symbiosis with V. radiata. The combination of effectors promoting nodulation in V. unguiculata and V. mungo differed, in both cases, NopT and NopAB were involved, suggesting they are key determinants for nodulation, and to a lesser extent, NopM1 and NopP1, which are additionally required for optimal symbiosis with V. mungo. In contrast, only one effector, NopP2, was identified as the cause of the incompatibility between ORS3257 and V. radiata. The identification of key effectors which promote symbiotic efficiency or render the interaction incompatible is important for the development of inoculation strategies to improve the growth of Vigna species cultivated in Africa and Asia.

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Immune response in SARS-CoV-2 infection: the role of interferons type I and type III

The Brazilian Journal of Infectious Diseases ◽

10.1016/j.bjid.2020.07.011 ◽

2020 ◽

Vol 24 (5) ◽

pp. 428-433 ◽

Cited By ~ 1

Author(s):

Caciane Portela Sousa ◽

Carlos Brites

Keyword(s):

Immune Response ◽

Type I ◽

Type Iii

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The Proteasome Acts as a Hub for Plant Immunity and Is Targeted by Pseudomonas Type III Effectors

PLANT PHYSIOLOGY ◽

10.1104/pp.16.00808 ◽

2016 ◽

Vol 172 (3) ◽

pp. 1941-1958 ◽

Cited By ~ 37

Author(s):

Suayib Üstün ◽

Arsheed Sheikh ◽

Selena Gimenez-Ibanez ◽

Alexandra Jones ◽

Vardis Ntoukakis ◽

...

Keyword(s):

Plant Immunity ◽

Type Iii Effectors ◽

Type Iii

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A Type III-A CRISPR-Cas system employs degradosome nucleases to ensure robust immunity

10.1101/545285 ◽

2019 ◽

Author(s):

Lucy Chou-Zheng ◽

Asma Hatoum-Aslan

Keyword(s):

Immune Response ◽

Staphylococcus Epidermidis ◽

Mobile Genetic Elements ◽

Genetic Elements ◽

Type Iii ◽

Robust Immune Response ◽

Functional Assays ◽

Dna And Rna ◽

Biochemical Analyses ◽

Phage Population

AbstractCRISPR-Cas systems provide sequence-specific immunity against phages and mobile genetic elements using CRISPR-associated nucleases guided by short CRISPR RNAs (crRNAs). Type III systems exhibit a robust immune response that can lead to the extinction of a phage population, a feat coordinated by a multi-subunit effector complex that destroys invading DNA and RNA. Here, we demonstrate that a model Type III system in Staphylococcus epidermidis relies upon the activities of two degradosome-associated nucleases, PNPase and RNase J2, to mount a successful defense. Genetic, molecular, and biochemical analyses reveal that PNPase promotes crRNA maturation, and both nucleases are required for efficient clearance of phage-derived nucleic acids. Furthermore, functional assays show that RNase J2 is essential for immunity against diverse mobile genetic elements originating from plasmid and phage. Altogether, our observations reveal the evolution of a critical collaboration between two nucleic acid degrading machines which ensures cell survival when faced with phage attack.

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Genome context influences evolutionary flexibility of nearly identical type III effectors in two phytopathogenic Pseudomonads

10.1101/2021.11.22.469601 ◽

2021 ◽

Author(s):

David A Baltrus ◽

Qian Feng ◽

Brian H Kvitko

Keyword(s):

Pseudomonas Syringae ◽

Evolutionary Dynamics ◽

Effector Proteins ◽

In Planta ◽

Genomic Context ◽

Type Iii Effectors ◽

Type Iii ◽

Genome Context ◽

The Impact ◽

Multiple Type

Integrative Conjugative Elements (ICEs) are replicons that can insert and excise from chromosomal locations in a site specific manner, can conjugate across strains, and which often carry a variety of genes useful for bacterial growth and survival under specific conditions. Although ICEs have been identified and vetted within certain clades of the agricultural pathogen Pseudomonas syringae, the impact of ICE carriage and transfer across the entire P. syringae species complex remains underexplored. Here we identify and vet an ICE (PmaICE-DQ) from P. syringae pv. maculicola ES4326, a strain commonly used for laboratory virulence experiments, demonstrate that this element can excise and conjugate across strains, and contains loci encoding multiple type III effector proteins. Moreover, genome context suggests that another ICE (PmaICE-AOAB) is highly similar in comparison with and found immediately adjacent to PmaICE-DQ within the chromosome of strain ES4326, and also contains multiple type III effectors. Lastly, we present passage data from in planta experiments that suggests that genomic plasticity associated with ICEs may enable strains to more rapidly lose type III effectors that trigger R-gene mediated resistance in comparison to strains where nearly isogenic effectors are not present in ICEs. Taken together, our study sheds light on a set of ICE elements from P. syringae pv. maculicola ES4326 and highlights how genomic context may lead to different evolutionary dynamics for shared virulence genes between strains.

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The Key Roles of Interferon Lambda in Human Molecular Defense against Respiratory Viral Infections

Pathogens ◽

10.3390/pathogens9120989 ◽

2020 ◽

Vol 9 (12) ◽

pp. 989

Author(s):

Alexey A. Lozhkov ◽

Sergey A. Klotchenko ◽

Edward S. Ramsay ◽

Herman D. Moshkoff ◽

Dmitry A. Moshkoff ◽

...

Keyword(s):

Immune Response ◽

Bacterial Infections ◽

Viral Infections ◽

Public Health Problem ◽

Negative Influence ◽

Epithelial Tissue ◽

Major Public Health Problem ◽

Type Iii ◽

Respiratory Viral Infections ◽

Type Iii Ifn

Interferons (IFN) are crucial for the innate immune response. Slightly more than two decades ago, a new type of IFN was discovered: the lambda IFN (type III IFN). Like other IFN, the type III IFN display antiviral activity against a wide variety of infections, they induce expression of antiviral, interferon-stimulated genes (MX1, OAS, IFITM1), and they have immuno-modulatory activities that shape adaptive immune responses. Unlike other IFN, the type III IFN signal through distinct receptors is limited to a few cell types, primarily mucosal epithelial cells. As a consequence of their greater and more durable production in nasal and respiratory tissues, they can determine the outcome of respiratory infections. This review is focused on the role of IFN-λ in the pathogenesis of respiratory viral infections, with influenza as a prime example. The influenza virus is a major public health problem, causing up to half a million lethal infections annually. Moreover, the virus has been the cause of four pandemics over the last century. Although IFN-λ are increasingly being tested in antiviral therapy, they can have a negative influence on epithelial tissue recovery and increase the risk of secondary bacterial infections. Therefore, IFN-λ expression deserves increased scrutiny as a key factor in the host immune response to infection.

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Genome-Assisted Development of a Diagnostic Protocol for Distinguishing High Virulence Pseudomonas syringae pv. tomato Strains

Plant Disease ◽

10.1094/pdis-08-14-0833-re ◽

2015 ◽

Vol 99 (4) ◽

pp. 527-534 ◽

Cited By ~ 5

Author(s):

Lisa A. Jones ◽

Surya Saha ◽

Alan Collmer ◽

Christine D. Smart ◽

Magdalen Lindeberg

Keyword(s):

New York ◽

Pseudomonas Syringae ◽

Genome Comparison ◽

Type Iii Effectors ◽

Type Iii ◽

Host Interaction ◽

Group I ◽

Virulent Strains ◽

High Virulence ◽

Relationship Of

A severe outbreak of bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, occurred in central New York in 2009. Isolate 09150, collected from this outbreak and subsequently named NYS-T1, was found to be highly virulent on tomato. To better understand the relationship of 09150 to other P. syringae strains and develop a diagnostic assay for aggressive strains of this pathogen, the 09150 genome was sequenced. Genome comparison revealed it to be highly similar to a previously sequenced isolate, T1. Genetic factors linked to host interaction including type III effectors, toxin biosynthetic genes, and elicitors of host innate immunity were identified. Type III effector repertoires were compared with other strains in the high virulence T1-like subgroup and lower virulence DC3000/P. syringae pv. maculicola subgroup within P. syringae phylogenetic Group I. Primers for conventional PCR were developed using sequences for avrA, hopW, conserved in the former subgroup and hopN, present in the latter. These were tested on isolates in the two subgroups, other pseudomonads, and other bacterial pathogens of tomato. Primers developed for avaA and hopW were diagnostic for more virulent strains of P. syringae pv. tomato while primers for hopN were diagnostic for P. syringae pv. tomato DC3000 and related P. syringe pv. maculicola strains. Primers designed against hopR distinguished both of these P. syringae subgroups from other P. syringae strains.

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