title: A genome-wide association study of a global rice panel reveals resistance in Oryza sativa to root-knot nematodes.
abstract: The root-knot nematode Meloidogyne graminicola is one of the most serious nematode pests worldwide and represents a major constraint on rice production. While variation in the susceptibility of Asian rice (Oryza sativa) exists, so far no strong and reliable resistance has been reported. Quantitative trait loci for partial resistance have been reported but no underlying genes have been tagged or cloned. Here, 332 accessions of the Rice Diversity Panel 1 were assessed for gall formation, revealing large variation across all subpopulations of rice and higher susceptibility in temperate japonica accessions. Accessions Khao Pahk Maw and LD 24 appeared to be resistant, which was confirmed in large pot experiments where no galls were observed. Detailed observations on these two accessions revealed no nematodes inside the roots 2 days after inoculation and very few females after 17 days (5 in Khao Pahk Maw and <1 in LD 24, in comparison with >100 in the susceptible controls). These two cultivars appear ideal donors for breeding root-knot nematode resistance. A genome-wide association study revealed 11 quantitative trait loci, two of which are close to epistatic loci detected in the Bala x Azucena population. The discussion highlights a small number of candidate genes worth exploring further, in particular many genes with lectin domains and genes on chromosome 11 with homology to the Hordeum Mla locus.
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB243UU, UK Current address: Department of Crop and Soil Science, Rivers State University of Science and Technology, Nigeria.
authors.forename: Stanley O N
authors.initials: SO
authors.lastname: Dimkpa
authors.affiliation: Department of Molecular Biotechnology, Ghent University (UGent), Coupure Links 653, B-9000, Ghent, Belgium.
authors.forename: Zobaida
authors.initials: Z
authors.lastname: Lahari
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB243UU, UK.
authors.forename: Roshi
authors.initials: R
authors.lastname: Shrestha
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB243UU, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Douglas
authors.affiliation: Department of Molecular Biotechnology, Ghent University (UGent), Coupure Links 653, B-9000, Ghent, Belgium.
authors.forename: Godelieve
authors.initials: G
authors.lastname: Gheysen
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB243UU, UK a.price@abdn.ac.
authors.forename: Adam H
authors.initials: AH
authors.lastname: Price
mesh_terms: D000818:Animals; D060467:Disease Resistance; D055106:Genome-Wide Association Study; D005838:Genotype; D012275:Oryza / Q000235:genetics* / Q000469:parasitology*; D010935:Plant Diseases / Q000235:genetics* / Q000469:parasitology; D018517:Plant Roots / Q000469:parasitology; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA; D014431:Tylenchoidea / Q000502:physiology*
keywords: GWAS; Mla; Nematode; lectin; resistance; rice diversity panel.