scholarly journals Transgressive segregation reveals mechanisms of Arabidopsis immunity to Brassica-infecting races of white rust (Albugo candida)

2019 ◽  
Vol 116 (7) ◽  
pp. 2767-2773 ◽  
Author(s):  
Volkan Cevik ◽  
Freddy Boutrot ◽  
Wiebke Apel ◽  
Alexandre Robert-Seilaniantz ◽  
Oliver J. Furzer ◽  
...  
Keyword(s):  
Positional Cloning ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Transgressive Segregation ◽  
Crop Species ◽  
Albugo Candida ◽  
White Rust ◽  
Adult Leaf ◽  
Genes Encoding ◽  
Race 2

Arabidopsis thaliana accessions are universally resistant at the adult leaf stage to white rust (Albugo candida) races that infect the crop species Brassica juncea and Brassica oleracea. We used transgressive segregation in recombinant inbred lines to test if this apparent species-wide (nonhost) resistance in A. thaliana is due to natural pyramiding of multiple Resistance (R) genes. We screened 593 inbred lines from an Arabidopsis 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 F2 progeny followed by positional cloning showed that resistance to an isolate of A. candida 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. An additional gene was identified that confers resistance to an isolate of A. candida race 9 (AcBoT) that infects B. oleracea. Thus, effector-triggered immunity conferred by distinct NLR-encoding genes in multiple A. thaliana accessions provides species-wide resistance to these crop pathogens.

The genetic framework of plant breeding

1981 ◽  
Vol 292 (1062) ◽  
pp. 407-419 ◽  
Keyword(s):  
Plant Breeding ◽  
Recombinant Inbred ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Single Seed Descent ◽  
Crop Species ◽  
Biometrical Genetics ◽  
Mendelian Genetics ◽  
Linkage Disequilibria ◽  
Random Samples

The phenotypic variation that the breeder must manipulate to produce improved genotypes typically contains contributions from both heritable and non-heritable sources as well as from interactions between them. The totality of this variation can be understood only in terms of a methodology such as that of biometrical genetics - an extension of classical Mendelian genetics that retains all of its analytical, interpretative and predictive powers but only in respect of the net or summed effects of all contributing gene loci. In biometrical genetics the statistics that describe the phenotypic distributions are themselves completely described by heritable components based on the known types of gene action and interaction in combination with nonheritable components defined by the statistical properties of the experimental design. Biometrical genetics provides a framework for investigating the genetical basis and justification for current plant breeding strategies that are typified by the production of F 1 hybrids at one extreme and recombinant inbred lines at the other. From the early generations of a cross it can extract estimates of the heritable components of the phenotypic distributions that provide all the information required to interpret the cause of F 1 heterosis and predict the properties of any generation that can subsequently be derived from the cross. Applications to crosses in experimental and crop species show that true overdominance is not a cause of F 1 heterosis, although spurious overdominance arising from linkage disequilibria and non-allelic interactions can be. Predictions of the phenotypic distributions and ranges of recombinant inbred lines that should be extractable from these crosses are confirmed by observations made on random samples of inbred families produced from them by single seed descent. Within these samples, recombinant inbred lines superior to existing inbred lines and their F 1 hybrids are observed with the predicted frequencies.

INHERITANCE OF RESISTANCE TO Albugo Candida Race 2 IN MUSTARD (Brassica Juncea (L.) Czern.)

1988 ◽  
Vol 68 (2) ◽  
pp. 297-300 ◽  
Author(s):  
A. S. TIWARI ◽  
G. A. PETRIE ◽  
R. K. DOWNEY
Keyword(s):  
Brassica Juncea ◽  
Nuclear Genes ◽  
Growth Chamber ◽  
Inheritance Of Resistance ◽  
Resistant Parent ◽  
Albugo Candida ◽  
White Rust ◽  
Race 2 ◽  
Made In

The inheritance of resistance to white rust (Albugo Candida) race 2 in mustard (Brassica juncea) was studied in crosses involving one resistant and two susceptible cultivars. Inoculations were made in a growth chamber followed by growth of the plants under greenhouse conditions. The reaction of the F1 was like the resistant parent, indicating that resistance is dominant and controlled by nuclear genes. Backcrosses of F1 plants to the resistant parent showed the same reactions as that of the resistant parent. Backcrosses of F1 to the susceptible parents segregated in a 1:1 ratio of resistant to susceptible. The F2 segregation of resistant and susceptible plants gave a good fit to a 3:1 ratio. The study revealed that resistance is monogenic and could be easily transferred to adapted susceptible genotypes via backcrossing.Key words: Brassica juncea, Albugo Candida, mustard, white rust

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 Characterization of White Rust of Perennial Pepperweed Caused by Albugo candida in California

Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 876-876 ◽  
Author(s):  
S. T. Koike ◽  
M. J. Sullivan ◽  
C. Southwick ◽  
C. Feng ◽  
J. C. Correll
Keyword(s):  
Its Region ◽  
Molecular Data ◽  
Crop Species ◽  
Albugo Candida ◽  
White Rust ◽  
Zoospore Release ◽  
White Blister ◽  
Differential Hosts ◽  
Noxious Weed

In California, perennial pepperweed (Lepidium latifolium) is an introduced Brassicaceae plant that is invasive, highly competitive, and listed as a noxious weed that grows in areas such as marshes, meadows, roadsides, and irrigation ditches. From 2008 through 2010, perennial pepperweed growing near farms in Monterey and Santa Clara counties was infected with white rust. Symptoms were light green-to-chlorotic spots on adaxial leaf surfaces and corresponding white, blister-like sori growing underneath the raised leaf epidermis on the abaxial surface. Sporangia were collected from lesions and used for DNA extraction. The internal transcribed spacer (ITS) region was amplified with primers ITS1/ITS4 and sequenced. The sequence matched with Albugo candida by BLAST against GenBank. On the basis of morphological and molecular data, the pathogen was confirmed to be A. candida. Pathogenicity was tested by scraping sporangia from infected leaves and spraying a suspension (1 × 105 sporangia/ml) onto pepperweed seedlings grown in pots. Plants were placed in an incubator at 100% relative humidity and 12°C for 48 h to induce zoospore release. Plants were subsequently maintained in a greenhouse. After 15 to 17 days, inoculated plants developed white rust symptoms and signs. Control plants sprayed with water did not become diseased. The experiment was completed two times with the same results. To determine the race of A. candida from perennial pepperweed, 4- to 5-week-old plants and 1- to 2-week-old seedlings of differential hosts (1–4) were inoculated in a similar fashion. The differential hosts were the following: Raphanus sativus (race 1), Brassica juncea cv. Burgonde (race 2A), B. juncea cv. Cutlass (race 2V), Armoracia rusticana (race 3), Capsella bursa-pastoris (race 4), Sisymbrium officinale (race 5), Rorippa islandica (race 6), B. rapa (B. campestris) cv. Torch (race 7A), B. rapa cvs. Reward, Cutlass, and AC Parkland (race 7V), B. nigra (race 8), B. oleracea (race 9), Sinapis alba (race 10), B. carinata (race 11), and perennial pepperweed as a control. White rust developed on pepperweed 10 to 14 days later but was not found on any of the differential hosts, indicating that this pathogen is not one of the currently described 11 races. The following commercial crop species were inoculated using the same method: arugula (Eruca sativa), Japanese mustard (B. campestris subsp. nipposinica), red mustard (B. juncea subsp. rugosa), tah tsai (B. campestris subsp. narinosa), cauliflower (B. oleracea subsp. botrytis), Chinese cabbage (B. campestris subsp. pekinensis), bok choy (B. rapa Chinensis group), broccoli raab (B. rapa subsp. rapa), and perennial pepperweed as a control. Only the perennial pepperweed developed white rust. To our knowledge, this is the first characterization of A. candida infecting perennial pepperweed in California. The disease has been documented on this plant in Colorado and also in Bulgaria, Portugal, and Spain. The host range information is important to growers because it indicates that the race currently infecting perennial pepperweed will not infect commercial crucifers. References: (1) P. A. Delwich and P. H. Williams. Cruciferae Newsl. 2:39, 1977. (2) C. B. Hill et al. Cruciferae Newsl. 13:112, 1988. (3) S. R. Rimmer et al. Can. J. Plant Pathol. 22:229, 2000. (4) P. R. Verma et al. Can. J. Bot. 53:1016, 1975.

scholarly journals Genetic and Molecular Analyses in Crosses of Race 2 and Race 7 of Albugo candida

2003 ◽  
Vol 93 (8) ◽  
pp. 959-965 ◽  
Author(s):  
Tika B. Adhikari ◽  
Jean Q. Liu ◽  
Snehlata Mathur ◽  
Chunren X. Wu ◽  
S. Roger Rimmer
Keyword(s):  
Dna Markers ◽  
Fragment Length Polymorphism ◽  
Random Amplified Polymorphic Dna ◽  
Dominant Gene ◽  
Avirulence Gene ◽  
Susceptible Host ◽  
Albugo Candida ◽  
White Rust ◽  
Differential Cultivars ◽  
Race 2

The inheritance of avirulence and polymorphic molecular markers in Albugo candida, the cause of white rust of crucifers, was studied in crosses of race 2 (Ac2), using isolates MiAc2-B1 or MiAc2-B5 (metalaxyl-insensitive and virulent to Brassica juncea cv. Burgonde) with race 7 (Ac7), using isolate MsAc7-A1 (metalaxyl-sensitive and virulent to B. rapa cv. Torch). Hybrids were obtained via co-inoculation onto a common susceptible host. Putative F1 progeny were selfed to produce F2 progeny. The parents and F1 progeny were examined for virulence on the differential cultivars B. juncea cv. Burgonde and B. rapa cv. Torch. Segregation of avirulence or virulence of F2 populations was analyzed on cv. Torch. Putative F1 hybrids were confirmed by random amplified polymorphic DNA markers specific for each parent. Avirulence or virulence of F 2 progeny to B. rapa cv. Torch suggested 3:1 in each of three populations, supporting the hypothesis of a single dominant avirulence gene. Amplified fragment length polymorphism markers also segregated in regular Mendelian fashion among F2 progeny derived from two F1 hybrids (Cr2-5 and Cr2-7) of Cross-2. This first putative avirulence gene in A. candida was designated AvrAc1. These results suggest that a single dominant gene controls avirulence in race Ac2 to B. rapa cv. Torch and provides further evidence for the gene-for-gene relationship in the Albugo-Brassica pathosystem.

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.

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.

Diverse sources of resistance to Spodoptera litura (F.) in groundnut

2019 ◽  
Vol 79 (01S) ◽  
Author(s):  
M. A. Saleem ◽  
G. K. Naidu ◽  
H. L. Nadaf ◽  
P. S. Tippannavar
Keyword(s):  
Recombinant Inbred ◽  
Spodoptera Litura ◽  
Hot Spot ◽  
Recombinant Inbred Lines ◽  
Insect Pest ◽  
Inbred Lines ◽  
Leaf Damage ◽  
Botanical Variety ◽  
Resistant Genotypes ◽  
Botanical Varieties

Spodoptera litura an important insect pest of groundnut causes yield loss up to 71% in India. Though many effective chemicals are available to control Spodoptera, host plant resistance is the most desirable, economic and eco-friendly strategy. In the present study, groundnut mini core (184), recombinant inbred lines (318) and elite genotypes (44) were studied for their reaction to Spodoptera litura under hot spot location at Dharwad. Heritable component of variation existed for resistance to Spodoptera in groundnut mini core, recombinant inbred lines and elite genotypes indicating scope for selection of Spodoptera resistant genotypes. Only 29 (15%) genotypes belonging to hypogaea, fastigiata and hirsuta botanical varieties under mini core set, 15 transgressive segregants belonging to fastigiata botanical variety among 318 recombinant inbred lines and three genotypes belonging to hypogaea and fastigiata botanical varieties under elite genotypes showed resistance to Spodoptera litura with less than 10% leaf damage. Negative correlation existed between resistance to Spodoptera and days to 50 per cent flowering indicating late maturing nature of resistant genotypes. Eight resistant genotypes (ICG 862, ICG 928, ICG 76, ICG 2777, ICG 5016, ICG 12276, ICG 4412 and ICG 9905) under hypogaea botanical variety also had significantly higher pod yield. These diverse genotypes could serve as potential donors for incorporation of Spodoptera resistance in groundnut.

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