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

2021 ◽  
Author(s):  
Baptiste Castel ◽  
Sebastian Fairhead ◽  
Oliver J. Furzer ◽  
Amey Redkar ◽  
Shanshan Wang ◽  
...  
Keyword(s):  
Resistance Locus ◽  
Albugo Candida ◽  
Trade Offs

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.

scholarly journals White rust species (Chromista, Peronosporomycetes, Albuginales, Albuginaceae) on common weeds in Hungary

2015 ◽  
pp. 30-33
Author(s):  
Tamás Tóth ◽  
György Kövics
Keyword(s):  
Morphological Characters ◽  
Amaranthus Retroflexus ◽  
Rust Disease ◽  
Albugo Candida ◽  
White Rust ◽  
Plant Parasite ◽  
Rust Diseases ◽  
The Family ◽  
Common Purslane

The obligate plant parasite fungi in the family Albuginaceae are responsible for causing white rust diseases on weeds and they are rather common worldwide. Weedy plants with characteristic symptoms have been collected in 2014 and 2015 on location Hajdú-Bihar and Jász-Nagykun-Szolnok counties in Hungary. The determination of the species were based on the morphological characters both pathogens and hosts. Albugo candida was determined on shepherd’s purse (Capsella bursa-pastoris). Common purslane (Portulaca oleracea) is a host for Wilsoniana portulacae. The fungus Wilsonia bliti (syn.: Albugo bliti), the causal agent of white rust disease was found on redroot pigweed (Amaranthus retroflexus).

Linkage mapping of genes controlling resistance to white rust (Albugo candida) in Brassica rapa (syn. campestris) and comparative mapping to Brassica napus and Arabidopsis thaliana

Genome ◽  
2002 ◽  
Vol 45 (1) ◽  
pp. 22-27 ◽  
Author(s):  
C Kole ◽  
P H Williams ◽  
S R Rimmer ◽  
T C Osborn
Keyword(s):  
Brassica Napus ◽  
Linkage Group ◽  
Brassica Rapa ◽  
Physical Map ◽  
Rflp Markers ◽  
Resistance Locus ◽  
Seedling Resistance ◽  
Albugo Candida ◽  
White Rust ◽  
Race 2

Genes for resistance to white rust (Albugo candida) in oilseed Brassica rapa were mapped using a recombinant inbred (RI) population and a genetic linkage map consisting of 144 restriction fragment length polymorphism (RFLP) markers and 3 phenotypic markers. Young seedlings were evaluated by inoculating cotyledons with A. candida race 2 (AC2) and race 7 (AC7) and scoring the interaction phenotype (IP) on a 0–9 scale. The IP of each line was nearly identical for the two races and the population showed bimodal distributions, suggesting that a single major gene (or tightly linked genes) controlled resistance to the two races. The IP scores were converted to categorical resistant and susceptible scores, and these data were used to map a single Mendelian gene controlling resistance to both races on linkage group 4 where resistance to race 2 had been mapped previously. A quantitative trait loci (QTL) mapping approach using the IP scores detected the same major resistance locus for both races, plus a second minor QTL effect for AC2 on linkage group 2. These results indicate that either a dominant allele at a single locus (Aca1) or two tightly linked loci control seedling resistance to both races of white rust in the biennial turnip rape cultivar Per. The map positions of white rust resistance genes in B. rapa and Brassica napus were compared and the results indicate where additional loci that have not been mapped may be located. Alignment of these maps to the physical map of the Arabidopsis genome identified regions to target for comparative fine mapping using this model organism.Key words: plant disease, oilseed Brassica, molecular markers.

scholarly journals Uncovering Trait Associations Resulting in Maximal Seed Yield in Winter and Spring Oilseed Rape

2021 ◽  
Vol 12 ◽  
Author(s):  
Laura Siles ◽  
Kirsty L. Hassall ◽  
Cristina Sanchis Gritsch ◽  
Peter J. Eastmond ◽  
Smita Kurup
Keyword(s):  
Oilseed Rape ◽  
Seed Yield ◽  
Complex Trait ◽  
Growth Conditions ◽  
Phenotypic Traits ◽  
Oilseed Crop ◽  
Crop Species ◽  
Trade Offs ◽  
Whole Plant ◽  
Plant Level

Seed yield is a complex trait for many crop species including oilseed rape (OSR) (Brassica napus), the second most important oilseed crop worldwide. Studies have focused on the contribution of distinct factors in seed yield such as environmental cues, agronomical practices, growth conditions, or specific phenotypic traits at the whole plant level, such as number of pods in a plant. However, how female reproductive traits contribute to whole plant level traits, and hence to seed yield, has been largely ignored. Here, we describe the combined contribution of 33 phenotypic traits within a B. napus diversity set population and their trade-offs at the whole plant and organ level, along with their interaction with plant level traits. Our results revealed that both Winter OSR (WOSR) and Spring OSR (SOSR); the two more economically important OSR groups in terms of oil production; share a common dominant reproductive strategy for seed yield. In this strategy, the main inflorescence is the principal source of seed yield, producing a good number of ovules, a large number of long pods with a concomitantly high number of seeds per pod. Moreover, we observed that WOSR opted for additional reproductive strategies than SOSR, presenting more plasticity to maximise seed yield. Overall, we conclude that OSR adopts a key strategy to ensure maximal seed yield and propose an ideal ideotype highlighting crucial phenotypic traits that could be potential targets for breeding.

Expression and relationships of resistance to white rust (Albugo candida) at cotyledonary, seedling, and flowering stages in Brassica juncea germplasm from Australia, China, and India

2007 ◽  
Vol 58 (3) ◽  
pp. 259 ◽  
Author(s):  
C. X. Li ◽  
K. Sivasithamparam ◽  
G. Walton ◽  
P. Salisbury ◽  
W. Burton ◽  
...  
Keyword(s):  
Plant Growth ◽  
Brassica Juncea ◽  
Environmental Conditions ◽  
Host Resistance ◽  
Growth Stages ◽  
Sources Of Resistance ◽  
Albugo Candida ◽  
White Rust ◽  
China And India ◽  
Canola Quality

White rust (Albugo candida) is a highly destructive disease of oilseed Brassicas such as Brassica juncea and B. rapa. Most commercial B. juncea or B. rapa varieties are highly susceptible and yield losses from combined infection of leaves and inflorescences can be up to 20% or 60% in Australia and India, respectively. In Australia, canola-quality B. juncea has been developed to extend oilseed Brassica production into lower rainfall areas, with the first commercial B. juncea canola-quality variety planned for release in 2006. It is essential to identify useful sources of host resistance in B. juncea as breeding and/or selection of material for resistance is the most cost-effective method of delivering control for farmers. Three experiments were undertaken under controlled-environmental conditions to identify the best methods of characterising host resistance and to identify sources of resistance in B. juncea germplasm from Australia, China, and India. Forty-four B. juncea genotypes, viz. 22 from India, 12 from Australia, and 10 from China, were tested. Four Chinese genotypes (CBJ-001, CBJ-002, CBJ-003, CBJ-004) and one Australian genotype (JR049) consistently showed high resistance to A. candida across the different plant growth stages against a pathotype prevailing in Australia. Similarly, the most susceptible genotypes (viz. Indian genotypes RH781, RL1359, RH819) were extremely susceptible irrespective of the plant growth stage. Overall, although disease severity on cotyledons and leaves at the different growth stages was significantly and positively correlated, there was, however, no significant correlation between the number of stagheads and any of the other disease parameters measured. Our study demonstrates that controlled-environmental conditions are suitable for rapid identification of resistant genotypes and that genotypes with high levels of resistance can be reliably identified at the cotyledonary, seedling, or flowering stages.

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