ATR2 from Arabidopsis-infecting downy mildew requires 4 TIR-NLR immune receptors for full recognition.

Arabidopsis Col-0 RPP2A and RPP2B confer recognition of Arabidopsis downy mildew (Hyaloperonospora arabidopsidis [Hpa]) isolate Cala2, but the identity of the recognized ATR2 effector was unknown. To reveal ATR2, an F population was generated from a cross between Hpa-Cala2 and Hpa-Noks1. We identified ATR2 as a non-canonical RxLR-type effector that carries a signal peptide, a dEER motif, and WY domains but no RxLR motif.

Genetic manipulation of Indian mustard genotypes with WRR-gene(s) confers resistance against Albugo candida.

Background: Brassica species is the second most important edible oilseed crop in India. Albugo candida (Pers.) Kuntze, a major oomycete disease of oilseed brassica causing white rust, leads to 60% yield loss globally.

Cell-specific RNA profiling reveals host genes expressed in Arabidopsis cells haustoriated by downy mildew.

The downy mildew oomycete Hyaloperonospora arabidopsidis, an obligate filamentous pathogen, infects Arabidopsis (Arabidopsis thaliana) by forming structures called haustoria inside host cells. Previous transcriptome analyses have revealed that host genes are specifically induced during infection; however, RNA profiling from whole-infected tissues may fail to capture key transcriptional events occurring exclusively in haustoriated host cells, where the pathogen injects virulence effectors to modulate host immunity. To determine interactions between Arabidopsis and H.

The integrated LIM-peptidase domain of the CSA1-CHS3/DAR4 paired immune receptor detects changes in DA1 peptidase inhibitors in Arabidopsis.

White blister rust, caused by the oomycete Albugo candida, is a widespread disease of Brassica crops. The Brassica relative Arabidopsis thaliana uses the paired immune receptor complex CSA1-CHS3/DAR4 to resist Albugo infection. The CHS3/DAR4 sensor NLR, which functions together with its partner, the helper NLR CSA1, carries an integrated domain (ID) with homology to DA1 peptidases.

The Arabidopsis TIR-NBS-LRR protein CSA1 guards BAK1-BIR3 homeostasis and mediates convergence of pattern- and effector-induced immune responses.

Arabidopsis BAK1/SERK3, a co-receptor of leucine-rich repeat pattern recognition receptors (PRRs), mediates pattern-triggered immunity (PTI). Genetic inactivation of BAK1 or BAK1-interacting receptor-like kinases (BIRs) causes cell death, but the direct mechanisms leading to such deregulation remains unclear. Here, we found that the TIR-NBS-LRR protein CONSTITUTIVE SHADE AVOIDANCE 1 (CSA1) physically interacts with BIR3, but not with BAK1.

Allelic variation in the Arabidopsis TNL CHS3/CSA1 immune receptor pair reveals two functional cell-death regulatory modes.

Some plant NLR immune receptors are encoded in head-to-head "sensor-executor" pairs that function together. Alleles of the NLR pair CHS3/CSA1 form three clades. The clade 1 sensor CHS3 contains an integrated domain (ID) with homology to regulatory domains, which is lacking in clades 2 and 3.

The Arabidopsis WRR4A and WRR4B paralogous NLR proteins both confer recognition of multiple Albugo candida effectors.

The oomycete Albugo candida causes white blister rust, an important disease of Brassica crops. Distinct races of A. candida are defined by their capacity to infect different host plant species.

Show me your ID: NLR immune receptors with integrated domains in plants.

Nucleotide-binding and leucine-rich repeat receptors (NLRs) are intracellular plant immune receptors that recognize pathogen effectors secreted into the plant cell. Canonical NLRs typically contain three conserved domains including a central nucleotide binding (NB-ARC) domain, C-terminal leucine-rich repeats (LRRs) and an N-terminal domain. A subfamily of plant NLRs contain additional noncanonical domain(s) that have potentially evolved from the integration of the effector targets in the canonical NLR structure.

An Improved Assembly of the Ac2V Genome Reveals the Expansion of the "CCG" Class of Effectors.

is an obligate oomycete pathogen that infects many plants in the Brassicaceae family. We resequenced the genome of isolate Ac2V using PacBio long reads and constructed an assembly augmented by Illumina reads. The Ac2VPB genome assembly is 10% larger and more contiguous compared with a previous version.

Evolutionary trade-offs at the Arabidopsis WRR4A resistance locus underpin alternate Albugo candida race recognition specificities.

The oomycete Albugo candida causes white rust of Brassicaceae, including vegetable and oilseed crops, and wild relatives such as Arabidopsis thaliana. Novel White Rust Resistance (WRR) genes from Arabidopsis enable new insights into plant/parasite co-evolution. WRR4A from Arabidopsis accession Columbia (Col-0) provides resistance to many but not all white rust races, and encodes a nucleotide-binding, leucine-rich repeat immune receptor.

A Species-Wide Inventory of NLR Genes and Alleles in Arabidopsis thaliana.

Infectious disease is both a major force of selection in nature and a prime cause of yield loss in agriculture. In plants, disease resistance is often conferred by nucleotide-binding leucine-rich repeat (NLR) proteins, intracellular immune receptors that recognize pathogen proteins and their effects on the host. Consistent with extensive balancing and positive selection, NLRs are encoded by one of the most variable gene families in plants, but the true extent of intraspecific NLR diversity has been unclear.

Transgressive segregation reveals mechanisms of immunity to -infecting races of white rust ().

accessions are universally resistant at the adult leaf stage to white rust () races that infect the crop species and We used transgressive segregation in recombinant inbred lines to test if this apparent species-wide (nonhost) resistance in is due to natural pyramiding of multiple () genes. We screened 593 inbred lines from an multiparent advanced generation intercross (MAGIC) mapping population, derived from 19 resistant parental accessions, and identified two transgressive segregants that are susceptible to the pathogen. These were crossed to each MAGIC parent, and analysis of resulting F progeny followed by positional cloning showed that resistance to an isolate of race 2 (Ac2V) can be explained in each accession by at least one of four genes encoding nucleotide-binding, leucine-rich repeat (NLR) immune receptors.

Publisher Correction: A downy mildew effector evades recognition by polymorphism of expression and subcellular localization.

The original version of this article contained an error in the author affiliations. Oliver J. Furzer was incorrectly associated with Department of Plant Sciences, College of Life Sciences, Wuhan University, 430072, Wuhan, China.

Diverse NLR immune receptors activate defence via the RPW8-NLR NRG1.

Most land plant genomes carry genes that encode RPW8-NLR Resistance (R) proteins. Angiosperms carry two RPW8-NLR subclasses: ADR1 and NRG1. ADR1s act as 'helper' NLRs for multiple TIR- and CC-NLR R proteins in Arabidopsis.

A downy mildew effector evades recognition by polymorphism of expression and subcellular localization.

Pathogen co-evolution with plants involves selection for evasion of host surveillance systems. The oomycete Hyaloperonospora arabidopsidis (Hpa) causes downy mildew on Arabidopsis, and race-specific interactions between Arabidopsis accessions and Hpa isolates fit the gene-for-gene model in which host resistance or susceptibility are determined by matching pairs of plant Resistance (R) genes and pathogen Avirulence (AVR) genes. Arabidopsis Col-0 carries R gene RPP4 that confers resistance to Hpa isolates Emoy2 and Emwa1, but its cognate recognized effector(s) were unknown.

Albugo candida race diversity, ploidy and host-associated microbes revealed using DNA sequence capture on diseased plants in the field.

Physiological races of the oomycete Albugo candida are biotrophic pathogens of diverse plant species, primarily the Brassicaceae, and cause infections that suppress host immunity to other pathogens. However, A. candida race diversity and the consequences of host immunosuppression are poorly understood in the field.

Distinct modes of derepression of an immune receptor complex by two different bacterial effectors.

Plant intracellular nucleotide-binding leucine-rich repeat (NLR) immune receptors often function in pairs to detect pathogen effectors and activate defense. The RRS1-R-RPS4 NLR pair recognizes the bacterial effectors AvrRps4 and PopP2 via an integrated WRKY transcription factor domain in RRS1-R that mimics the effector's authentic targets. How the complex activates defense upon effector recognition is unknown.

A Suppressor/Avirulence Gene Combination in Determines Race Specificity in .

The pathosystem of and diploid biotrophic oomycete () has been a model for investigating the molecular basis of Flor's gene-for-gene hypothesis. The isolates -Noks1 and -Cala2 are virulent on accession RMX-A02 whilst an F generated from a cross between these two isolates was avirulent. The F progeny segregated 3,1 (avirulent, virulent), indicating a single major effect locus in this pathogen.

represents an excellent bioassay for shear forces induced in ground-based microgravity simulators (clinostat and random positioning machine).

Ground-based facilities, such as clinostats and random positioning machines aiming at simulating microgravity conditions, are tools to prepare space experiments and identify gravity-related signaling pathways. A prerequisite is that the facilities are operated in an appropriate manner and potentially induced non-gravitational effects, such as shearing forces, have to be taken into account. Dinoflagellates, here , as fast and sensitive reporter system for shear stress and hydrodynamic gradients, were exposed on a clinostat (constant rotation around one axis, 60 rpm) or in a random positioning machine, that means rotating around two axes, whose velocity and direction were chosen at random.

Protein-protein interactions in the RPS4/RRS1 immune receptor complex.

Plant NLR (Nucleotide-binding domain and Leucine-rich Repeat) immune receptor proteins are encoded by Resistance (R) genes and confer specific resistance to pathogen races that carry the corresponding recognized effectors. Some NLR proteins function in pairs, forming receptor complexes for the perception of specific effectors. We show here that the Arabidopsis RPS4 and RRS1 NLR proteins are both required to make an authentic immune complex.

Albugo-imposed changes to tryptophan-derived antimicrobial metabolite biosynthesis may contribute to suppression of non-host resistance to Phytophthora infestans in Arabidopsis thaliana.

Background: Plants are exposed to diverse pathogens and pests, yet most plants are resistant to most plant pathogens. Non-host resistance describes the ability of all members of a plant species to successfully prevent colonization by any given member of a pathogen species. White blister rust caused by Albugo species can overcome non-host resistance and enable secondary infection and reproduction of usually non-virulent pathogens, including the potato late blight pathogen Phytophthora infestans on Arabidopsis thaliana.

Pathogen perception by NLRs in plants and animals: Parallel worlds.

Intracellular NLR (Nucleotide-binding domain and Leucine-rich Repeat-containing) receptors are sensitive monitors that detect pathogen invasion of both plant and animal cells. NLRs confer recognition of diverse molecules associated with pathogen invasion. NLRs must exhibit strict intramolecular controls to avoid harmful ectopic activation in the absence of pathogens.

R-gene variation across Arabidopsis lyrata subspecies: effects of population structure, selection and mating system.

Background: Examining allelic variation of R-genes in closely related perennial species of Arabidopsis thaliana is critical to understanding how population structure and ecology interact with selection to shape the evolution of innate immunity in plants. We finely sampled natural populations of Arabidopsis lyrata from the Great Lakes region of North America (A. l.

Characterization of a JAZ7 activation-tagged Arabidopsis mutant with increased susceptibility to the fungal pathogen Fusarium oxysporum.

In Arabidopsis, jasmonate (JA)-signaling plays a key role in mediating Fusarium oxysporum disease outcome. However, the roles of JASMONATE ZIM-domain (JAZ) proteins that repress JA-signaling have not been characterized in host resistance or susceptibility to this pathogen. Here, we found most JAZ genes are induced following F.

Comparative analysis of plant immune receptor architectures uncovers host proteins likely targeted by pathogens.

Background: Plants deploy immune receptors to detect pathogen-derived molecules and initiate defense responses. Intracellular plant immune receptors called nucleotide-binding leucine-rich repeat (NLR) proteins contain a central nucleotide-binding (NB) domain followed by a series of leucine-rich repeats (LRRs), and are key initiators of plant defense responses. However, recent studies demonstrated that NLRs with non-canonical domain architectures play an important role in plant immunity.