title: Single nucleotide polymorphisms in the allene oxide synthase 2 gene are associated with field resistance to late blight in populations of tetraploid potato cultivars.
abstract: The oomycete Phytophthora infestans causes late blight, the most relevant disease of potato (Solanum tuberosum) worldwide. Field resistance to late blight is a complex trait. When potatoes are cultivated under long day conditions in temperate climates, this resistance is correlated with late plant maturity, an undesirable characteristic. Identification of natural gene variation underlying late blight resistance not compromised by late maturity will facilitate the selection of resistant cultivars and give new insight in the mechanisms controlling quantitative pathogen resistance. We tested 24 candidate loci for association with field resistance to late blight and plant maturity in a population of 184 tetraploid potato individuals. The individuals were genotyped for 230 single nucleotide polymorphisms (SNPs) and 166 microsatellite alleles. For association analysis we used a mixed model, taking into account population structure, kinship, allele substitution and interaction effects of the marker alleles at a locus with four allele doses. Nine SNPs were associated with maturity corrected resistance (P < 0.001), which collectively explained 50% of the genetic variance of this trait. A major association was found at the StAOS2 locus encoding allene oxide synthase 2, a key enzyme in the biosynthesis of jasmonates, plant hormones that function in defense signaling. This finding supports StAOS2 as being one of the factors controlling natural variation of pathogen resistance.
authors.affiliation: Max Planck Institute for Plant Breeding Research, Department for Plant Breeding and Genetics, Cologne, Germany.
authors.forename: Karolina
authors.initials: K
authors.lastname: Pajerowska-Mukhtar
authors.forename: Benjamin
authors.initials: B
authors.lastname: Stich
authors.forename: Ute
authors.initials: U
authors.lastname: Achenbach
authors.forename: Agim
authors.initials: A
authors.lastname: Ballvora
authors.forename: Jens
authors.initials: J
authors.lastname: Lübeck
authors.forename: Josef
authors.initials: J
authors.lastname: Strahwald
authors.forename: Eckhard
authors.initials: E
authors.lastname: Tacke
authors.forename: Hans-Reinhard
authors.initials: HR
authors.lastname: Hofferbert
authors.forename: Evgeniya
authors.initials: E
authors.lastname: Ilarionova
authors.forename: Diana
authors.initials: D
authors.lastname: Bellin
authors.forename: Birgit
authors.initials: B
authors.lastname: Walkemeier
authors.forename: Rico
authors.initials: R
authors.lastname: Basekow
authors.forename: Birgit
authors.initials: B
authors.lastname: Kersten
authors.forename: Christiane
authors.initials: C
authors.lastname: Gebhardt
mesh_terms: D003517:Cyclopentanes / Q000378:metabolism; D008040:Genetic Linkage; D005838:Genotype; D007113:Immunity, Innate / Q000235:genetics*; D019746:Intramolecular Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism; D010641:Phenotype; D055750:Phytophthora infestans / Q000502:physiology*; D010935:Plant Diseases / Q000235:genetics / Q000469:parasitology*; D020641:Polymorphism, Single Nucleotide; D011198:Solanum tuberosum / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000469:parasitology*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; C011006:jasmonic acid; D019746:Intramolecular Oxidoreductases; C021377:hydroperoxide isomerase