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.

Development of an agronomically superior blackleg resistant canola cultivar in Brassica napus L. using doubled haploidy

1995 ◽  
Vol 75 (2) ◽  
pp. 437-439 ◽  
Author(s):  
G. R. Stringam ◽  
V. K. Bansal ◽  
M. R. Thiagarajah ◽  
D. F. Degenhardt ◽  
J. P. Tewari
Keyword(s):  
Brassica Napus ◽  
Doubled Haploid ◽  
Leptosphaeria Maculans ◽  
Resistance Breeding ◽  
Breeding Method ◽  
Brassica Napus L ◽  
Breeding Lines ◽  
University Of Alberta ◽  
Blackleg Resistance ◽  
The University

The doubled haploid breeding method and greenhouse screening using cotyledon bio-assay were successfully applied to transfer blackleg resistance from the Australian cultivar Maluka (Brassicas napus), into susceptible advanced B. napus lines from the University of Alberta. This approach for blackleg resistance breeding was effective and efficient as several superior blackleg resistant breeding lines were identified within 4 yr from the initial cross. One of these lines (91–21864NA) was entered in the 1993 trials of the Western Canada Canola/Rapeseed Recommending Committee. Key words: Blackleg resistance, Leptosphaeria maculans, doubled haploid, Brassica napus

scholarly journals Stabilization of Resistance to Leptosphaeria maculans in Brassica napus–B. juncea Recombinant Lines and Its Introgression into Spring-Type Brassica napus

Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1208-1214 ◽  
Author(s):  
A.-M. Chèvre ◽  
H. Brun ◽  
F. Eber ◽  
J.-C. Letanneur ◽  
P. Vallee ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Dominant Gene ◽  
Leptosphaeria Maculans ◽  
Polygenic Resistance ◽  
Breeding Lines ◽  
Blackleg Resistance ◽  
Backcross Populations ◽  
Spring Type ◽  
The Stability ◽  
High Level

The value of Katanning Early Maturing (KEM) breeding lines from Western Australia, derived from Brassica napus × B. juncea crosses, was assessed as a source of germplasm for resistance to blackleg disease (caused by Leptosphaeria maculans) in spring-type oilseed rape cultivars. The stability of blackleg resistance in these KEM lines was related to key cytological characteristics to determine why there are poor levels of introgression of this resistance into progeny. Promising recombinant KEM lines were crossed with the spring-type B. napus cv. Dunkeld, which has useful polygenic resistance to blackleg, and screened for resistance. The lines were analyzed cytologically for pairing of bivalents in each generation to aid in the selection of stable recombinant lines. KEM recombinant lines showing regular meiotic behavior and a high level of blackleg resistance were obtained for the first time. We also showed that the stable introgression of the B. juncea resistance from the KEM lines into a ‘Dunkeld’ background was possible. Inoculation of selfing and backcross populations with isolates of L. maculans having different AvrLm genes indicated that the B. juncea resistance gene, Rlm6, had been introgressed into a B. napus spring-type cultivar carrying polygenic resistance. The combination of both resistances would enhance the overall effectiveness of resistance against L. maculans. This is clearly needed in Australia and France where cultivars relying upon single dominant gene-based resistance for their effectiveness have proved not durable.

scholarly journals Recent Findings Unravel Genes and Genetic Factors Underlying Leptosphaeria maculans Resistance in Brassica napus and Its Relatives

2020 ◽  
Vol 22 (1) ◽  
pp. 313
Author(s):  
Aldrin Y. Cantila ◽  
Nur Shuhadah Mohd Saad ◽  
Junrey C. Amas ◽  
David Edwards ◽  
Jacqueline Batley
Keyword(s):  
Brassica Napus ◽  
Genetic Factors ◽  
Quantitative Resistance ◽  
Genetic Resistance ◽  
Leptosphaeria Maculans ◽  
Gene Interaction ◽  
R Gene ◽  
R Genes ◽  
Blackleg Resistance ◽  
Avr Gene

Among the Brassica oilseeds, canola (Brassica napus) is the most economically significant globally. However, its production can be limited by blackleg disease, caused by the fungal pathogen Lepstosphaeria maculans. The deployment of resistance genes has been implemented as one of the key strategies to manage the disease. Genetic resistance against blackleg comes in two forms: qualitative resistance, controlled by a single, major resistance gene (R gene), and quantitative resistance (QR), controlled by numerous, small effect loci. R-gene-mediated blackleg resistance has been extensively studied, wherein several genomic regions harbouring R genes against L. maculans have been identified and three of these genes were cloned. These studies advance our understanding of the mechanism of R gene and pathogen avirulence (Avr) gene interaction. Notably, these studies revealed a more complex interaction than originally thought. Advances in genomics help unravel these complexities, providing insights into the genes and genetic factors towards improving blackleg resistance. Here, we aim to discuss the existing R-gene-mediated resistance, make a summary of candidate R genes against the disease, and emphasise the role of players involved in the pathogenicity and resistance. The comprehensive result will allow breeders to improve resistance to L. maculans, thereby increasing yield.

scholarly journals Fine mapping of Brassica napus blackleg resistance gene Rlm1 through bulked segregant RNA sequencing

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Fuyou Fu ◽  
Xunjia Liu ◽  
Rui Wang ◽  
Chun Zhai ◽  
Gary Peng ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Resistance Gene ◽  
Rna Sequencing ◽  
Catalytic Domain ◽  
Leptosphaeria Maculans ◽  
Snp Markers ◽  
Specific Pcr ◽  
Dual Specificity ◽  
Kinase Catalytic Domain ◽  
Allele Specific

Abstract The fungal pathogen Leptosphaeria maculans causes blackleg disease on canola and rapeseed (Brassica napus) in many parts of the world. A B. napus cultivar, ‘Quinta’, has been widely used for the classification of L. maculans into pathogenicity groups. In this study, we confirmed the presence of Rlm1 in a DH line (DH24288) derived from B. napus cultivar ‘Quinta’. Rlm1 was located on chromosome A07, between 13.07 to 22.11 Mb, using a BC1 population made from crosses of F1 plants of DH16516 (a susceptible line) x DH24288 with bulked segregant RNA Sequencing (BSR-Seq). Rlm1 was further fine mapped in a 100 kb region from 19.92 to 20.03 Mb in the BC1 population consisting of 1247 plants and a F2 population consisting of 3000 plants using SNP markers identified from BSR-Seq through Kompetitive Allele-Specific PCR (KASP). A potential resistance gene, BnA07G27460D, was identified in this Rlm1 region. BnA07G27460D encodes a serine/threonine dual specificity protein kinase, catalytic domain and is homologous to STN7 in predicted genes of B. rapa and B. oleracea, and A. thaliana. Robust SNP markers associated with Rlm1 were developed, which can assist in introgression of Rlm1 and confirm the presence of Rlm1 gene in canola breeding programs.

Identification and mapping of a novel blackleg resistance locus LepR4 in the progenies from Brassica napus × B. rapa subsp. sylvestris

2012 ◽  
Vol 126 (2) ◽  
pp. 307-315 ◽  
Author(s):  
Fengqun Yu ◽  
Richard K. Gugel ◽  
H. Randy Kutcher ◽  
Gary Peng ◽  
S. Roger Rimmer
Keyword(s):  
Brassica Napus ◽  
Resistance Locus ◽  
Blackleg Resistance

scholarly journals Breakdown of a Brassica rapa subsp. sylvestris Single Dominant Blackleg Resistance Gene in B. napus Rapeseed by Leptosphaeria maculans Field Isolates in Australia

Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 752-752 ◽  
Author(s):  
H. Li ◽  
K. Sivasithamparam ◽  
M. J. Barbetti
Keyword(s):  
Brassica Napus ◽  
Resistance Gene ◽  
Disease Severity ◽  
Brassica Rapa ◽  
Oilseed Rape ◽  
Leptosphaeria Maculans ◽  
Blackleg Disease ◽  
Field Isolates ◽  
Western Australian ◽  
Lower Stem

Blackleg, caused by Leptosphaeria maculans, is a major disease of oilseed rape (Brassica napus) grown in Canada, Europe, and Australia. Cv. Surpass 400 was released in Australia in 2000 as the most resistant cultivar to L. maculans. It carries a single dominant resistance gene from B. rapa subsp. sylvestris. This cultivar usually shows a hypersensitive response to L. maculans characterized by small, dark brown lesions that are necrotic, localized, and without pycnidia on cotyledons, leaves, and stems. However, in 2001 on a Western Australian experimental farm, a small proportion of the lesions on the lower stem and crown region of cv. Surpass 400 were typical of those observed in susceptible cultivars, which were brown, necrotic lesions with a darker margin, but they contained fewer pycnidia. Forty seedlings of cv. Surpass 400 and susceptible cv. Westar were inoculated with pycnidiospore suspensions (106/ml) of each of 18 isolates taken from lesions on cv. Surpass 400. All 18 isolates caused collapse of cotyledons of susceptible cv. Westar. Four of these isolates caused large cotyledon lesions with some pycnidia on cv. Surpass 400. Three of these four isolates were subsequently inoculated onto 60 seedlings per isolate, at each of the four cotyledon lobes of each seedling of the two cultivars. Inoculated plants were assessed for disease severity on cotyledons and transplanted to the field 14 days after inoculation. The cotyledons of inoculated cv. Surpass 400 showed characteristic large, necrotic lesions with pycnidia, while the cotyledons of cv. Westar had collapsed and contained a mass of pycnidia. Blackleg disease severity in the crown region of the stem was assessed at 2 weeks before harvest. Fifty-four percent of the cv. Surpass 400 transplanted inoculated plants subsequently developed susceptible symptoms of crown cankers on stems. These symptoms were deep, girdling, brown lesions on the plant crowns with some pycnidia. One hundred percent of cv. Westar plants were infected and dead at this stage. This confirmed the ability of these field isolates to overcome the single dominant resistance gene present in cv. Surpass 400. To our knowledge, this is the first report of breakdown of a single dominant B. rapa subsp. sylvestris gene based resistance to blackleg in oilseed rape in the field.

scholarly journals In-silico identification and differential expression of putative disease resistance-related genes within the collinear region of Brassica napus blackleg resistance locus LepR2’ in Brassica oleracea

2020 ◽  
Vol 61 (5) ◽  
pp. 879-890 ◽  
Author(s):  
Mohammad Rashed Hossain ◽  
Mostari Jahan Ferdous ◽  
Jong-In Park ◽  
Arif Hasan Khan Robin ◽  
Sathishkumar Natarajan ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Brassica Napus ◽  
Resistance Locus ◽  
R Gene ◽  
R Genes ◽  
Blackleg Resistance ◽  
B Genome ◽  
Expression Of Genes ◽  
C Genome ◽  
R Loci

Abstract Blackleg disease, caused by Leptosphaeria maculans, greatly affects the production of cabbage (Brassica oleracea). However, definitive R-gene(s) are yet to be identified in this crop. In contrast, a number of R-loci have been identified in A- or B-genome crops. Identification of few resistant cabbage genotypes indicates the presence of R-genes in this C-genome crop. High ancestral synteny between Brassica genomes suggests that the collinear regions of known A- or B-genome R-loci may also contain functional R-genes in the C-genome. Strong resistance was observed in the cotyledons of cabbage inbred line SCNU-98 against two L. maculans isolates, 03–02 s and 00–100 s. We investigated the collinear region of the Brassica napus blackleg resistance locus LepR2’ in B. oleracea since both isolates of L. maculans contain corresponding avirulence genes. The locus was collinear to a 5.8 Mbp genomic segment of B. oleracea chromosome C09 containing 13 genes that have putative disease resistance-related domains. High expression of genes Bo9g117290 and Bo9g111510 against isolate 00–100 s, and high expression of genes Bo9g126150 and Bo9g111490 against both isolates in the resistant-line SCNU-98 indicate their putative roles in blackleg resistance, which remained to be functionally verified. This work enhances our understanding of R-gene-mediated resistance to blackleg in cabbage.

Genetic mapping of the Leptosphaeria maculans avirulence gene corresponding to the LepR1 resistance gene of Brassica napus

2011 ◽  
Vol 124 (3) ◽  
pp. 505-513 ◽  
Author(s):  
Kaveh Ghanbarnia ◽  
Derek J. Lydiate ◽  
S. Roger Rimmer ◽  
Genyi Li ◽  
H. Randy Kutcher ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Genetic Mapping ◽  
Resistance Gene ◽  
Leptosphaeria Maculans ◽  
Avirulence Gene

scholarly journals Genetic Control and Host Range of Avirulence Toward Brassica napus Cultivars Quinta and Jet Neuf in Leptosphaeria maculans

2001 ◽  
Vol 91 (1) ◽  
pp. 70-76 ◽  
Author(s):  
M. H. Balesdent ◽  
A. Attard ◽  
D. Ansan-Melayah ◽  
R. Delourme ◽  
M. Renard ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Resistance Gene ◽  
Single Gene ◽  
Leptosphaeria Maculans ◽  
Avirulence Gene ◽  
Gene Interactions ◽  
Deleterious Gene ◽  
Or Genes ◽  
Avr Gene ◽  
Avr Genes

Leptosphaeria maculans causes blackleg of oilseed rape. Gene-for-gene interactions between race PG3 and Brassica napus cv. Quinta were related to interaction between the fungal avirulence (Avr) gene AvrLm1 and the corresponding resistance gene Rlm1. AvrLm1 isolates were aviru-lent on cvs. Doublol, Vivol, Columbus, and Capitol, and no recombinant phenotypes were observed in the progeny of two AvrLm1 × avrLm1 crosses, suggesting that all of these cultivars may possess Rlm1 or genes displaying the same recognition spectrum, or that a cluster of Avr genes is present at the Avrlm1 locus. In one cross, segregation distortion was observed at the AvrLm1 locus that could be explained by interaction between AvrLm1 and one unlinked deleterious gene, termed Del1. Incompatibility toward cvs. Jet Neuf and Darmor.bzh was governed by a single gene, unlinked to AvrLm1 or Del1. This avirulence gene was termed AvrLm4. Preliminary plant genetic analysis suggested the occurrence of a corresponding dominant resistance gene, termed Rlm4, present in the Quinta line analyzed and linked to Rlm1.

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