Theoretical and Applied Genetics (2017) 130, 29-39

Z.W. Zhang, G.J. Ma, J. Zhao, S.G. Markell and L.L. Qi (2017)
Discovery and introgression of the wild sunflower-derived novel downy mildew resistance gene Pl₁₉ in confection sunflower (Helianthus annuus L.)
Theoretical and Applied Genetics 130 (1), 29-39
Abstract: Wild Helianthus annuus accession PI 435414 exhibited resistance to downy mildew, which is one of the most destructive diseases to sunflower production globally. Evaluation of the 140 BC₁F_2:3 families derived from the cross of CMS CONFSCLB1 and PI 435414 against Plasmopara halstedii race 734 revealed that a single dominant gene controls downy mildew resistance in the population. Bulked segregant analysis conducted in the BC₁F₂ population with 860 simple sequence repeat (SSR) markers indicated that the resistance derived from wild H. annuus was associated with SSR markers located on linkage group (LG) 4 of the sunflower genome. To map and tag this resistance locus, designated Pl₁₉, 140 BC₁F₂ individuals were used to construct a linkage map of the gene region. Two SSR markers, ORS963 and HT298, were linked to Pl₁₉ within a distance of 4.7 cM. After screening 27 additional single nucleotide polymorphism (SNP) markers previously mapped to this region, two flanking SNP markers, NSA_003564 and NSA_006089, were identified as surrounding the Pl₁₉ gene at a distance of 0.6 cM from each side. Genetic analysis indicated that Pl₁₉ is different from Pl₁₇, which had previously been mapped to LG4, but is closely linked to Pl₁₇. This new gene is highly effective against the most predominant and virulent races of P. halstedii currently identified in North America and is the first downy mildew resistance gene that has been transferred to confection sunflower. The selected resistant germplasm derived from homozygous BC₂F₃ progeny provides a novel gene for use in confection sunflower breeding programs.
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Link to article at publishers website
Database assignments for author(s): Samuel G. Markell

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plasmopara halstedii	Sunflower (Helianthus annuus)