title: Conditional QTL underlying resistance to late blight in a diploid potato population.
abstract: A large number of quantitative trait loci (QTL) for resistance to late blight of potato have been reported with a "conventional" method in which each phenotypic trait reflects the cumulative genetic effects for the duration of the disease process. However, as genes controlling response to disease may have unique contributions with specific temporal features, it is important to consider the phenotype as dynamic. Here, using the net genetic effects evidenced at consecutive time points during disease development, we report the first conditional mapping of QTL underlying late blight resistance in potato under five environments in Peru. Six conditional QTL were mapped, one each on chromosome 2, 7 and 12 and three on chromosome 9. These QTL represent distinct contributions to the phenotypic variation at different stages of disease development. By comparison, when conventional mapping was conducted, only one QTL was detected on chromosome 9. This QTL was the same as one of the conditional QTL. The results imply that conditional QTL reflect genes that function at particular stages during the host-pathogen interaction. The dynamics revealed by conditional QTL mapping could contribute to the understanding of the molecular mechanism of late blight resistance and these QTL could be used to target genes for marker development or manipulation to improve resistance.
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Huazhong Agricultural University, Ministry of Education, National Center for Vegetable Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China.
authors.forename: Jingcai
authors.initials: J
authors.lastname: Li
authors.forename: Hannele
authors.initials: H
authors.lastname: Lindqvist-Kreuze
authors.forename: Zhendong
authors.initials: Z
authors.lastname: Tian
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Botao
authors.initials: B
authors.lastname: Song
authors.forename: Juan
authors.initials: J
authors.lastname: Landeo
authors.forename: Leticia
authors.initials: L
authors.lastname: Portal
authors.forename: Manuel
authors.initials: M
authors.lastname: Gastelo
authors.forename: Julio
authors.initials: J
authors.lastname: Frisancho
authors.forename: Laura
authors.initials: L
authors.lastname: Sanchez
authors.forename: Dennis
authors.initials: D
authors.lastname: Meijer
authors.forename: Conghua
authors.initials: C
authors.lastname: Xie
authors.forename: Merideth
authors.initials: M
authors.lastname: Bonierbale
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D060467:Disease Resistance / Q000235:genetics; D008040:Genetic Linkage; D055750:Phytophthora infestans / Q000472:pathogenicity; D010935:Plant Diseases / Q000276:immunology*; D040641:Quantitative Trait Loci; D011198:Solanum tuberosum / Q000235:genetics* / Q000276:immunology* / Q000469:parasitology