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.

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.

Identification and mapping of a third blackleg resistance locus in Brassica napus derived from B. rapa subsp. sylvestris

Genome ◽  
2008 ◽  
Vol 51 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Fengqun Yu ◽  
Derek J. Lydiate ◽  
S. Roger Rimmer
Keyword(s):  
Brassica Napus ◽  
Linkage Group ◽  
Resistance Gene ◽  
Leptosphaeria Maculans ◽  
Resistance Locus ◽  
Dominant Allele ◽  
Breeding Lines ◽  
Disease Reaction ◽  
Blackleg Resistance ◽  
Map Location

The spectrum of resistance to isolates of Leptosphaeria maculans and the map location of a new blackleg resistance gene found in the canola cultivar Brassica napus ‘Surpass 400’ are described. Two blackleg resistance genes, LepR1 and LepR2, from B. rapa subsp. sylvestris and introgressed in B. napus were identified previously. ‘Surpass 400’ also has blackleg resistance introgressed from B. rapa subsp. sylvestris. Using 31 diverse isolates of L. maculans, the disease reaction of ‘Surpass 400’ was compared with those of the resistant breeding lines AD9 (which contains LepR1), AD49 (which contains LepR2), and MC1-8 (which contains both LepR1 and LepR2). The disease reaction on ‘Surpass 400’ was different from those observed on AD9 and MC1-8, indicating that ‘Surpass 400’ carries neither LepR1 nor both LepR1 and LepR2 in combination. Disease reactions of ‘Surpass 400’ to most of the isolates tested were indistinguishable from those of AD49, which suggested ‘Surpass 400’ might contain LepR2 or a similar resistance gene. Classical genetic analysis of F1 and BC1 plants showed that a dominant allele conferred resistance to isolates of L. maculans in ‘Surpass 400’. The resistance gene, which mapped to B. napus linkage group N10 in an interval of 2.9 cM flanked by microsatellite markers sR12281a and sN2428Rb and 11.7 cM below LepR2, was designated LepR3. A 9 cM region of the B. napus genome containing LepR3 was found to be syntenic with a segment of Arabidopsis chromosome 5.

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

Genetic control of immunity to Turnip mosaic virus (TuMV) pathotype 1 in Brassica rapa (Chinese cabbage)

Genome ◽  
2014 ◽  
Vol 57 (8) ◽  
pp. 419-425 ◽  
Author(s):  
Derek J. Lydiate ◽  
Rachel L. Rusholme Pilcher ◽  
Erin E. Higgins ◽  
John A. Walsh
Keyword(s):  
Mosaic Virus ◽  
Resistance Gene ◽  
Brassica Rapa ◽  
Chinese Cabbage ◽  
Turnip Mosaic Virus ◽  
Rflp Markers ◽  
Resistance Locus ◽  
Chromosome 6 ◽  
A Genome ◽  
Virus Interactions

Turnip mosaic virus (TuMV) is the major virus infecting crops of the genus Brassica worldwide. A dominant resistance gene, TuRB01b, that confers immunity to the virus isolate UK 1 (a representative pathotype 1 isolate of TuMV) on Brassica rapa was identified in the Chinese cabbage cultivar Tropical Delight. The TuRB01b locus was mapped to a 2.9-cM interval on B. rapa chromosome 6 (A6) that was flanked by RFLP markers pN101e1 and pW137e1. This mapping used a first backcross (B1) population segregating for the resistance gene at TuRB01b and sets of RFLP markers employed in previous mapping experiments in Brassica. Virus–plant interaction phenotypes were assayed in inbred progeny derived from B1 individuals to allow different virus isolates to be tested. Comparative mapping confirmed that A6 of B. rapa was equivalent to chromosome 6 of Brassica napus (A6) and that the map position of TuRB01b in B. rapa could be identical to that of TuRB01 in B. napus. Detailed evaluation of plant–virus interactions showed that TuRB01 and TuRB01b had indistinguishable specificities to a range of TuMV isolates. The possibility that TuRB01 and TuRB01b represent similar or identical alleles at the same A genome resistance locus suggests that B. napus acquired TuRB01 from the B. rapa gene pool.

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.

Resolving the aphid resistance locus Sd-1 on a BAC contig within a sub-telomeric region of Malus linkage group 7

Genome ◽  
2002 ◽  
Vol 45 (5) ◽  
pp. 939-945 ◽  
Author(s):  
Volkan Cevik ◽  
Graham J King
Keyword(s):  
Linkage Group ◽  
Physical Map ◽  
Aphid Resistance ◽  
Economic Damage ◽  
Telomeric Region ◽  
Resistance Locus ◽  
Average Insert Size ◽  
Distance Ratio ◽  
Bac Contig ◽  
Bac Clones

Aphids cause serious physical and economic damage to most major crops throughout the world, and there is a pressing requirement to isolate genes conferring aphid resistance. The Sd-1 locus in Malus spp. (apple) confers resistance against the rosy leaf-curling aphid (Dysaphis devecta Wlk.), and was recently positioned within a 1.3-cM region on linkage group 7, flanked by molecular markers. These markers were used as a basis for development of a BAC contig spanning the locus, together with adapter-mediated amplification of flanking sequences to obtain BAC insert-end sequences, and fingerprinting of BAC clones. Approximately 800 kb of the Sd-1 genomic region was covered by 19 overlapping BACs, with an average insert size of 75–150 kb. The physical – genetic distance ratio was estimated at 460 kb/cM, although the distribution of recombination events was irregular with respect to estimated physical distance. Recombinant analysis and development of new markers allowed Sd-1 to be positioned within an interval of approximately 180 kb located on either of two overlapping BACs. From one of these, an insert end sequence showed a significant degree of similarity to nucleotide binding site – leucine rich repeat (NBS–LRR) resistance genes. Fluorescent in situ hybridization (FISH) of BAC clones within the contig enabled positioning and orientation of the locus within a euchromatic region, very close to the telomere of linkage group 7.Key words: aphid, resistance gene, apple, Malus, physical map.

Physical Mapping of the liguleless Linkage Group in Sorghum bicolor Using Rice RFLP-Selected Sorghum BACs

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1983-1992
Author(s):  
Michael S Zwick ◽  
M Nurul Islam-Faridi ◽  
Don G Czeschin ◽  
Rod A Wing ◽  
Gary E Hart ◽  
...  
Keyword(s):  
Linkage Group ◽  
Linkage Map ◽  
Physical Mapping ◽  
Fluorescent In Situ Hybridization ◽  
Physical Map ◽  
Rflp Markers ◽  
Full Agreement ◽  
Group I ◽  
Chromosome I

Abstract Physical mapping of BACs by fluorescent in situ hybridization (FISH) was used to analyze the liguleless (lg-1) linkage group in sorghum and compare it to the conserved region in rice and maize. Six liguleless-associated rice restriction fragment length polymorphism (RFLP) markers were used to select 16 homeologous sorghum BACs, which were in turn used to physically map the liguleless linkage group in sorghum. Results show a basic conservation of the liguleless region in sorghum relative to the linkage map of rice. One marker which is distal in rice is more medial in sorghum, and another marker which is found within the linkage group in rice is on a different chromosome in sorghum. BACs associated with linkage group I hybridize to chromosome It, which was identified by using FISH in a sorghum cytogenetic stock trisomic for chromosome I (denoted It), and a BAC associated with linkage group E hybridized to an unidentified chromosome. Selected BACs, representing RFLP loci, were end-cloned for RFLP mapping, and the relative linkage order of these clones was in full agreement with the physical data. Similarities in locus order and the association of RFLP-selected BAC markers with two different chromosomes were found to exist between the linkage map of the liguleless region in maize and the physical map of the liguleless region in sorghum.

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.

scholarly journals 085 Development of a Cleaved Amplified pPolymorphic Sequence (CAP) and Restriction Fragment Length Polymorphisms (RFLPs) Linked to the Mi Root-knot Nematode (Meloidogyne incognita, race 1) Resistance Gene in Peach [Prunus persica (L.) Batsch]

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 403C-403
Author(s):  
Anne M. Gillen ◽  
Fredrick A. Bliss
Keyword(s):  
Linkage Group ◽  
Linkage Map ◽  
Genetic Linkage ◽  
Rapd Markers ◽  
Genetic Linkage Map ◽  
Prunus Persica ◽  
Rapd Marker ◽  
Rflp Markers ◽  
Resistance Locus ◽  
Root Knot Nematode

Peach rootstock breeding may be accelerated by utilization of molecular markers linked to the root-knot nematode resistance locus (Mi) to screen segregating populations. A genetic linkage map was constructed using RFLP markers in an F2 population (PMP2) that is segregating for this locus. PMP2 is derived from a controlled cross of the relatively diverse peach rootstocks Harrow Blood (susceptible) and Okinawa (homozygous resistant). Bulked Segregant Analysis was applied using RAPD markers. A single small (227 base pairs) RAPD marker was found to be linked to the dominant resistant allele of Mi at a distance of 10 cM. This new marker joined the Mi locus to the RFLP linkage map and showed that two dominant RFLP markers are located between the RAPD marker and Mi. RFLPS are expensive, time-consuming and RAPD markers are unreliable, and therefore both are unsuitable for screening breeding populations. We attempted to convert the RAPD marker to a more breeder-friendly CAPS marker. The converted CAP marker was dominant. Attempts to convert the CAP marker to a co-dominant marker were not successful. The utility of the CAP marker was tested in an open pollinated F2 population derived from the F1 parent of PMP2 and in several rootstocks. The genetic linkage map was compared to other Prunus maps. The PMP2 linkage group containing the Mi locus can be related to the peach × almond linkage group which contains the phosphoglucomutase Pgm-1 locus.

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