A Novel Grape Downy Mildew Resistance Locus from Vitis rupestris

Abstract Background Downy mildew, the most devastating disease of spinach (Spinacia oleracea L.), is caused by the oomycete Peronospora effusa [=P. farinosa f. sp. spinaciae]. The P. effusa shows race specificities to the resistant host and comprises 19 reported races and many novel isolates. Sixteen new P. effusa races were identified during the past three decades, and the new pathogen races are continually overcoming the genetic resistances used in commercial cultivars. A spinach breeding population derived from the cross between cultivars Whale and Lazio was inoculated with P. effusa race 16 in an environment-controlled facility; disease response was recorded and genotyped using genotyping by sequencing (GBS). The main objective of this study was to identify resistance-associated single nucleotide polymorphism (SNP) markers from the cultivar Whale against the P. effusa race 16. Results Association analysis conducted using GBS markers identified six significant SNPs (S3_658,306, S3_692697, S3_1050601, S3_1227787, S3_1227802, S3_1231197). The downy mildew resistance locus from cultivar Whale was mapped to a 0.57 Mb region on chromosome 3, including four disease resistance candidate genes (Spo12736, Spo12784, Spo12908, and Spo12821) within 2.69–11.28 Kb of the peak SNP. Conclusions Genomewide association analysis approach was used to map the P. effusa race 16 resistance loci and identify associated SNP markers and the candidate genes. The results from this study could be valuable in understanding the genetic basis of downy mildew resistance, and the SNP marker will be useful in spinach breeding to select resistant lines.

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Identification and Characterization of Simple Sequence Repeats (SSR) Markers Associated with Downy Mildew Resistance Locus “<i>RPV1</i>” in Grapes

Advances in Bioscience and Biotechnology ◽

10.4236/abb.2021.1211024 ◽

2021 ◽

Vol 12 (11) ◽

pp. 371-387

Author(s):

Neetu Goyal ◽

Akshay Nag ◽

Roshni R. Samarth ◽

Anuradha Upadhyay ◽

Kashmir Singh

Keyword(s):

Downy Mildew ◽

Ssr Markers ◽

Simple Sequence Repeats ◽

Resistance Locus ◽

Downy Mildew Resistance ◽

Mildew Resistance ◽

Identification And Characterization ◽

Simple Sequence

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The downy mildew resistance locus Pp523 is located on chromosome C8 of Brassica oleracea L.

Plant Breeding ◽

10.1111/j.1439-0523.2011.01904.x ◽

2011 ◽

Vol 131 (1) ◽

pp. 170-175 ◽

Cited By ~ 10

Author(s):

Jorge D. Carlier ◽

Claudia A. Alabaça ◽

Paula S. Coelho ◽

António A. Monteiro ◽

José M. Leitão

Keyword(s):

Brassica Oleracea ◽

Downy Mildew ◽

Resistance Locus ◽

Downy Mildew Resistance ◽

Mildew Resistance ◽

Brassica Oleracea L

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SCAR and CAPS markers flanking the Brassica oleracea L. Pp523 downy mildew resistance locus demarcate a genomic region syntenic to the top arm end of Arabidopsis thaliana L. chromosome 1

Euphytica ◽

10.1007/s10681-007-9414-6 ◽

2007 ◽

Vol 157 (1-2) ◽

pp. 215-221 ◽

Cited By ~ 17

Author(s):

Mário Farinhó ◽

Paula Coelho ◽

António Monteiro ◽

José Leitão

Keyword(s):

Arabidopsis Thaliana ◽

Brassica Oleracea ◽

Downy Mildew ◽

Genomic Region ◽

Chromosome 1 ◽

Resistance Locus ◽

Downy Mildew Resistance ◽

Mildew Resistance ◽

Caps Markers ◽

Brassica Oleracea L

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Development of Sequence Characterized Amplified Region Markers Linked to Downy Mildew Resistance in Broccoli

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.127.4.597 ◽

2002 ◽

Vol 127 (4) ◽

pp. 597-601 ◽

Cited By ~ 15

Author(s):

Janel L. Giovannelli ◽

Mark W. Farnham ◽

Min Wang ◽

Allan E. Strand

Keyword(s):

Downy Mildew ◽

Genetic Markers ◽

Resistance Genes ◽

Rapd Markers ◽

Dominant Gene ◽

Screening Tools ◽

Resistance Locus ◽

Downy Mildew Resistance ◽

Scar Markers ◽

Mildew Resistance

Downy mildew, caused by the fungal parasite Peronospora parasitica (Pers.: Fr.) Fr., is a destructive disease of Brassica oleracea L. crops, including broccoli (B. oleracea, Italica Group). The development and deployment of downy mildew resistant broccoli cultivars is a priority for breeders and producers. Identification of genetic markers linked to downy mildew resistance genes should facilitate selection for resistance and pyramiding of resistance genes into cultivars. The objectives of this study were to 1) identify RAPD markers linked to a single dominant gene for resistance in broccoli, 2) clone and sequence the linked RAPD markers, and 3) develop and evaluate SCAR markers as screening tools for resistance. Bulked segregant analysis led to the identification of eight linked RAPD markers following a screen of 848 decamers. Two of the linked RAPD fragments, UBC359620 and OPM16750, were converted to dominant SCAR markers linked in coupling to the resistance locus at 6.7 and 3.3 cM, respectively. The SCAR marker based on UBC359620 sequence exhibited less accuracy (94%) than the original RAPD (96%) in differentiating resistant and susceptible plants, but the accuracy (97%) of the OPM16750-SCAR was not different than the original RAPD. These SCAR markers are among the first genetic markers found linked to a gene conferring cotyledon-stage downy mildew resistance in B. oleracea. Results of this work provide breeders with useful information and tools for the systematic development of resistant cultivars.

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SCREENING TECHNIQUES FOR DOWNY MILDEW RESISTANCE IN GHERKIN CUCUMBERS

International Journal of Geomate ◽

10.21660/2017.40.2603 ◽

2017 ◽

Vol 13 (40) ◽

Author(s):

Piyavadee Charoenwattana

Keyword(s):

Downy Mildew ◽

Downy Mildew Resistance ◽

Mildew Resistance ◽

Screening Techniques

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Mutants of downy mildew resistance in Lactuca sativa (lettuce).

Genetics ◽

10.1093/genetics/137.3.867 ◽

1994 ◽

Vol 137 (3) ◽

pp. 867-874

Author(s):

P A Okubara ◽

P A Anderson ◽

O E Ochoa ◽

R W Michelmore

Keyword(s):

Molecular Marker ◽

Downy Mildew ◽

Genomic Dna ◽

Spontaneous Mutation ◽

Multigene Families ◽

Downy Mildew Resistance ◽

Bremia Lactucae ◽

Wild Type ◽

Mildew Resistance ◽

Recessive Mutations

Abstract As part of our investigation of disease resistance in lettuce, we generated mutants that have lost resistance to Bremia lactucae, the casual fungus of downy mildew. Using a rapid and reliable screen, we identified 16 distinct mutants of Latuca sativa that have lost activity of one of four different downy mildew resistance genes (Dm). In all mutants, only a single Dm specificity was affected. Genetic analysis indicated that the lesions segregated as single, recessive mutations at the Dm loci. Dm3 was inactivated in nine of the mutants. One of five Dm 1 mutants was selected from a population of untreated seeds and therefore carried a spontaneous mutation. All other Dm1, Dm3, Dm5/8 and Dm7 mutants were derived from gamma- or fast neutron-irradiated seed. In two separate Dm 1 mutants and in each of the eight Dm3 mutants analyzed, at least one closely linked molecular marker was absent. Also, high molecular weight genomic DNA fragments that hybridized to a tightly linked molecular marker in wild type were either missing entirely or were truncated in two of the Dm3 mutants, providing additional evidence that deletions had occurred in these mutants. Absence of mutations at loci epistatic to the Dm genes suggested that such loci were either members of multigene families, were critical for plant survival, or encoded components of duplicated pathways for resistance; alternatively, the genes determining downy mildew resistance might be limited to the Dm loci.

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