scholarly journals WRR4 Encodes a TIR-NB-LRR Protein That Confers Broad-Spectrum White Rust Resistance in Arabidopsis thaliana to Four Physiological Races of Albugo candida

2008 ◽  
Vol 21 (6) ◽  
pp. 757-768 ◽  
Author(s):  
M. Hossein Borhan ◽  
Nick Gunn ◽  
Abigail Cooper ◽  
Sigrun Gulden ◽  
Mahmut Tör ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Broad Spectrum ◽  
Rust Resistance ◽  
Functional Expression ◽  
Oilseed Crop ◽  
Transgenic Expression ◽  
Albugo Candida ◽  
Physiological Races ◽  
White Rust ◽  
Race 4

White blister rust in the Brassicaceae is emerging as a superb model for exploring how plant biodiversity has channeled speciation of biotrophic parasites. The causal agents of white rust across a wide breadth of cruciferous hosts currently are named as variants of a single oomycete species, Albugo candida. The most notable examples include a major group of physiological races that each are economically destructive in a different vegetable or oilseed crop of Brassica juncea (A. candida race 2), B. rapa (race 7), or B. oleracea (race 9); or parasitic on wild crucifers such as Capsella bursa-pastoris (race 4). Arabidopsis thaliana is innately immune to these races of A. candida under natural conditions; however, it commonly hosts its own molecularly distinct subspecies of A. candida (A. candida subsp. arabidopsis). In the laboratory, we have identified several accessions of Arabidopsis thaliana (e.g.,. Ws-3) that can permit varying degrees of rust development following inoculation with A. candida races 2, 4, and 7, whereas race 9 is universally incompatible in Arabidopsis thaliana and nonrusting resistance is the most prevalent outcome of interactions with the other races. Subtle variation in resistance phenotypes is evident, observed initially with an isolate of A. candida race 4, indicating additional genetic variation. Therefore, we used the race 4 isolate for map-based cloning of the first of many expected white rust resistance (WRR) genes. This gene was designated WRR4 and encodes a cytoplasmic toll-interleukin receptor-like nucleotide-binding leucine-rich repeat receptor-like protein that confers a dominant, broad-spectrum white rust resistance in the Arabidopsis thaliana accession Columbia to representative isolates of A. candida races 2, 4, 7, and 9, as verified by transgenic expression of the Columbia allele in Ws-3. The WRR4 protein requires functional expression of the lipase-like protein EDS1 but not the paralogous protein PAD4, and confers full immunity that masks an underlying nonhypersensitive incompatibility in Columbia to A. candida race 4. This residual incompatibility is independent of functional EDS1.

scholarly journals Albugo candida (white rust) suppresses resistance to downy mildew pathogens in Arabidopsis thaliana

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 474-476 ◽  
Author(s):  
A.J. Cooper ◽  
A. Woods-Tör ◽  
E.B. Holub
Keyword(s):  
Arabidopsis Thaliana ◽  
Downy Mildew ◽  
Rust Resistance ◽  
Downy Mildew Resistance ◽  
Bremia Lactucae ◽  
Structural Class ◽  
Albugo Candida ◽  
White Rust ◽  
Downy Mildews ◽  
Hyaloperonospora Parasitica

Arabidopsis thaliana accessions were inoculated with incompatible isolates of downy mildews, following pre-inoculation with compatible Albugo candida. Three isolates of Hyaloperonospora parasitica subsp. A. thaliana, an isolate of H. parasitica subsp. Brassica oleracea and one Bremia lactucae (lettuce) isolate were included. All downy mildews sporulated on A. thaliana, suggesting A. candida suppresses broad-spectrum downy mildew resistance. The white rust resistance gene, RAC5, is being investigated. The resistance phenotype associated with RAC5 seems not to involve a hypersensitive response. RAC5 has been mapped telomeric of nga106 on chromosome 5, in a region lacking NB-LRR genes, the most common structural class of resistance genes known in A. thaliana.

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

2021 ◽  
Author(s):  
Baptiste Castel ◽  
Sebastian Fairhead ◽  
Oliver J Furzer ◽  
Amey Redkar ◽  
Shanshan Wang ◽  
...  
Keyword(s):  
Receptor Protein ◽  
Resistance Locus ◽  
Oilseed Crop ◽  
Arabidopsis Accession ◽  
Oilseed Crops ◽  
Albugo Candida ◽  
White Rust ◽  
Plant Parasite ◽  
Trade Offs ◽  
Race 4

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 Col-0 provides resistance to many but not all white rust races, and encodes a nucleotide-binding (NB), leucine-rich repeat (LRR) (NLR) immune receptor protein. Col-0 WRR4A resistance is broken by a Col-0-virulent isolate of A. candida race 4 (AcEx1). We identified an allele of WRR4A in Arabidopsis accession Oy-0 and other accessions that confers full resistance to AcEx1. WRR4AOy-0 carries a C-terminal extension required for recognition of AcEx1, but reduces recognition of several effectors recognized by the WRR4A_Col-0 allele. WRR4A_Oy-0 confers full resistance to AcEx1 when expressed as a transgene in the oilseed crop Camelina sativa.

scholarly journals The Arabidopsis TIR-NB-LRR Gene RAC1 Confers Resistance to Albugo candida (White Rust) and Is Dependent on EDS1 but not PAD4

2004 ◽  
Vol 17 (7) ◽  
pp. 711-719 ◽  
Author(s):  
Mohammad H. Borhan ◽  
Eric B. Holub ◽  
Jim L. Beynon ◽  
Kevin Rozwadowski ◽  
S. Roger Rimmer
Keyword(s):  
Positional Cloning ◽  
Rust Resistance ◽  
Interleukin 1 ◽  
Dominant Gene ◽  
Leucine Rich Repeat ◽  
Albugo Candida ◽  
White Rust ◽  
Candida Isolate ◽  
Turn Structure ◽  
Lrr Domain

Resistance to Albugo candida isolate Acem1 is conferred by a dominant gene, RAC1, in accession Ksk-1 of Arabidopsis thaliana. This gene was isolated by positional cloning and is a member of the Drosophila toll and mammalian interleukin-1 receptor (TIR) nucleotide-binding site leucine-rich repeat (NB-LRR) class of plant resistance genes. Strong identity of the TIR and NB domains was observed between the predicted proteins encoded by the Ksk-1 allele and the allele from an Acem1-susceptible accession Columbia (Col) (99 and 98%, respectively). However, major differences between the two predicted proteins occur within the LRR domain and mainly are confined to the β-strand/β-turn structure of the LRR. Both proteins contain 14 imperfect repeats. RAC1-mediated resistance was analyzed further using mutations in defense regulation, including: pad4-1, eds1-1, and NahG, in the presence of the RAC1 allele from Ksk-1. White rust resistance was completely abolished by eds1-1 but was not affected by either pad4-1 or NahG.

scholarly journals Basic Compatibility of Albugo candida in Arabidopsis thaliana and Brassica juncea Causes Broad-Spectrum Suppression of Innate Immunity

2008 ◽  
Vol 21 (6) ◽  
pp. 745-756 ◽  
Author(s):  
A. J. Cooper ◽  
A. O. Latunde-Dada ◽  
A. Woods-Tör ◽  
J. Lynn ◽  
J. A. Lucas ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Powdery Mildew ◽  
Downy Mildew ◽  
Brassica Juncea ◽  
Broad Spectrum ◽  
Secondary Infection ◽  
Nonhost Resistance ◽  
Susceptible Host ◽  
Albugo Candida ◽  
In The Wild

A biotrophic parasite often depends on an intrinsic ability to suppress host defenses in a manner that will enable it to infect and successfully colonize a susceptible host. If the suppressed defenses otherwise would have been effective against alternative pathogens, it follows that primary infection by the “suppressive” biotroph potentially could enhance susceptibility of the host to secondary infection by avirulent pathogens. This phenomenon previously has been attributed to true fungi such as rust (basidiomycete) and powdery mildew (ascomycete) pathogens. In our study, we observed broad-spectrum suppression of host defense by the oomycete Albugo candida (white blister rust) in the wild crucifer Arabidopsis thaliana and a domesticated relative, Brassica juncea. A. candida subsp. arabidopsis suppressed the “runaway cell death” phenotype of the lesion mimic mutant lsd1 in Arabidopsis thaliana in a sustained manner even after subsequent inoculation with avirulent Hyaloperonospora arabidopsis (Arabidopsis thaliana downy mildew). In sequential inoculation experiments, we show that preinfection by virulent Albugo candida can suppress disease resistance in cotyledons to several downy mildew pathogens, including contrasting examples of genotype resistance to H. arabidopsis in Arabidopsis thaliana that differ in the R protein and modes of defense signaling used to confer the resistance; genotype specific resistance in B. juncea to H. parasitica (Brassica downy mildew; isolates derived from B. juncea); species level (nonhost) resistance in both crucifers to Bremia lactucae (lettuce downy mildew) and an isolate of the H. parasitica race derived from Brassica oleracea; and nonhost resistance in B. juncea to H. arabidopsis. Broad-spectrum powdery mildew resistance conferred by RPW8 also was suppressed in Arabidopsis thaliana to two morphotypes of Erysiphe spp. following pre-infection with A. candida subsp. arabidopsis.

scholarly journals Inheritance of resistance to Albugo candida in rape (Brassica napus L.)

1983 ◽  
Vol 25 (5) ◽  
pp. 420-424 ◽  
Author(s):  
Z. Fan ◽  
S. R. Rimmer ◽  
B. R. Stefansson
Keyword(s):  
Brassica Napus ◽  
Genetic Study ◽  
Rust Resistance ◽  
Resistant Cultivar ◽  
Inheritance Of Resistance ◽  
Brassica Napus L ◽  
Albugo Candida ◽  
White Rust ◽  
Dominant Genes

Canadian cultivars of Brassica napus are resistant to white rust caused by Albugo candida while many cultivars of this species grown in China are susceptible. Two Chinese lines susceptible to race 7, GCL, and 2282-9, and one Canadian resistant cultivar, 'Regent,' were chosen for a genetic study of resistance to this pathogen. Inheritance of white rust resistance is conditioned by independent dominant genes at three loci; these were designated Ac7-1, Ac7-2, and Ac7-3. The resistance is conferred by dominance at any one of the three loci and plants with recessive alleles at all loci are susceptible. Since different F2 and BC ratios were obtained for populations derived from different individual plants of 'Regent,' this 'Regent' population is not homogeneous for resistance to white rust. All 'Regent' plants appear to be homogeneous for resistance at two loci while, in addition, some may also carry resistance at a third locus.

scholarly journals WRR4,a broad-spectrum TIR-NB-LRR gene fromArabidopsis thalianathat confers white rust resistance in transgenic oilseed brassica crops

2010 ◽  
Vol 11 (2) ◽  
pp. 283-291 ◽  
Author(s):  
MOHAMMAD HOSSEIN BORHAN ◽  
ERIC B. HOLUB ◽  
COLIN KINDRACHUK ◽  
MANSOUR OMIDI ◽  
GHAZALEH BOZORGMANESH-FRAD ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Rust Resistance ◽  
White Rust ◽  
Brassica Crops

scholarly journals BjuWRR1, a CC-NB-LRR gene identified in Brassica juncea, confers resistance to white rust caused by Albugo Candida

2019 ◽  
Author(s):  
Heena Arora ◽  
K. Lakshmi Padmaja ◽  
Kumar Paritosh ◽  
Nitika Mukhi ◽  
A. K. Tewari ◽  
...  
Keyword(s):  
Genetic Transformation ◽  
Brassica Juncea ◽  
Gene Pool ◽  
Evolutionary Dynamics ◽  
Genomic Sequence ◽  
Oilseed Crop ◽  
R Gene ◽  
East European ◽  
Albugo Candida ◽  
White Rust

AbstractWhite rust caused by oomycete pathogen Albugo candida is a significant disease of crucifer crops including Brassica juncea (mustard), a major oilseed crop of the Indian subcontinent. Earlier a resistance-conferring locus named AcB1-A5.1 was mapped in an east European gene pool line of B. juncea – Donskaja-IV. This line was tested along with some other lines of B. juncea (AABB), B. rapa (AA) and B. nigra (BB) for resistance to six isolates of A. candida collected from different mustard growing regions of India. Donskaja-IV was found to be completely resistant to all the tested isolates. Sequencing of a BAC spanning the locus AcB1-A5.1 showed the presence of a single CC-NB-LRR protein encoding R gene. The genomic sequence of the putative R gene with its native promoter and terminator was used for the genetic transformation of a susceptible Indian gene pool line Varuna and was found to confer complete resistance to all the isolates. This is the first white rust resistance-conferring gene described from Brassica species and has been named BjuWRR1. Allelic variants of the gene in B. juncea germplasm and orthologues in the Brassicaceae genomes were studied to understand the evolutionary dynamics of the BjuWRR1 gene.HighlightBjuWRR1, a CNL type R gene, was identified from an east European gene pool line of Brassica juncea and validated for conferring resistance to white rust by genetic transformation.

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

2021 ◽  
Author(s):  
Amey Redkar ◽  
Volkan Cevik ◽  
Kate Bailey ◽  
Oliver J. Furzer ◽  
Sebastian Fairhead ◽  
...  
Keyword(s):  
Resistance Proteins ◽  
Albugo Candida ◽  
Secretion Signal ◽  
White Rust ◽  
Brassica Crops ◽  
Broad Spectrum Resistance ◽  
White Blister ◽  
White Blister Rust ◽  
Race 4 ◽  
Important Disease

The oomycete Albugo candida causes white blister rust, an important disease of Brassica crops. Distinct races of A. candida are defined by their specificity for infecting different host species. The White Rust Resistance 4 (WRR4) locus in Col-0 accession of Arabidopsis thaliana contains three genes that encode TIR-NLR resistance proteins. The Col-0 alleles of WRR4A and WRR4B confer resistance to at least four A. candida races (2, 7 and 9 from B. juncea, B. rapa and B. oleracea, respectively, and Race 4 from Capsella bursa-pastoris). Resistance mediated by both paralogs can be overcome by Col-0-virulent isolates of Race 4. After comparing repertoires of candidate effectors in resisted and resistance-breaking strains, we used transient co-expression in tobacco or Arabidopsis to identify effectors recognized by WRR4A and WRR4B. A library of CCG effectors from four A. candida races was screened for WRR4A- or WRR4B- dependent elicitation of hypersensitive response (HR). These CCG genes were validated for WRR-dependent HR by bombardment assays in wild type Col-0, wrr4A or wrr4B mutants. Our analysis revealed eight WRR4A-recognized CCGs and four WRR4B-recognized CCGs. Remarkably, the N-terminal region of 100 amino acids after the secretion signal is sufficient for WRR4A recognition of these eight recognized effectors. This multiple recognition capacity potentially explains the broad-spectrum resistance to many A. candida races conferred by WRR4 paralogs.

Identification of RFLP markers linked to the white rust resistance gene (Acr) in mustard (Brassica juncea (L.) Czern. and Coss.)

Genome ◽  
1998 ◽  
Vol 41 (4) ◽  
pp. 626-628 ◽  
Author(s):  
W Y Cheung ◽  
R K Gugel ◽  
B S Landry
Keyword(s):  
Brassica Juncea ◽  
Rust Resistance ◽  
Single Gene ◽  
Rapid Identification ◽  
Rflp Markers ◽  
Rust Disease ◽  
Albugo Candida ◽  
White Rust ◽  
Rflp Map ◽  
Race 2

White rust and staghead, caused by Albugo candida, is an economically important disease of Brassica juncea and Brassica rapa crops in western Canada. The identification of genes for white rust resistance in these crops and the development of molecular markers for these genes will allow the rapid identification of resistant germplasm and should accelerate the development of white rust resistant cultivars. In this study, 119 F1-derived doubled-haploid progeny lines of a cross between white rust susceptible (J90-4317) and white rust resistant (J90-2733) B. juncea lines were evaluated for resistance to A. candida race 2. A single gene (Acr) responsible for conferring resistance to this pathogen was mapped on a densely populated B. juncea RFLP map developed earlier. A cosegregating RFLP marker (X140a) and two other closely linked RFLP markers (X42 and X83) were identified; the latter two markers were 2.3 and 4 cM from the Acr locus, respectively. These markers may be useful for marker-assisted selection and map-based cloning of this gene.Key words: Brassica juncea, mustard, Albugo candida, white rust, disease resistance, RFLP.

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