title: Linked, if not the same, Mi-1 homologues confer resistance to tomato powdery mildew and root-knot nematodes.
abstract: On the short arm of tomato chromosome 6, a cluster of disease resistance (R) genes have evolved harboring the Mi-1 and Cf genes. The Mi-1 gene confers resistance to root-knot nematodes, aphids, and whiteflies. Previously, we mapped two genes, Ol-4 and Ol-6, for resistance to tomato powdery mildew in this cluster. The aim of this study was to investigate whether Ol-4 and Ol-6 are homologues of the R genes located in this cluster. We show that near-isogenic lines (NIL) harboring Ol-4 (NIL-Ol-4) and Ol-6 (NIL-Ol-6) are also resistant to nematodes and aphids. Genetically, the resistance to nematodes cosegregates with Ol-4 and Ol-6, which are further fine-mapped to the Mi-1 cluster. We provide evidence that the composition of Mi-1 homologues in NIL-Ol-4 and NIL-Ol-6 is different from other nematode-resistant tomato lines, Motelle and VFNT, harboring the Mi-1 gene. Furthermore, we demonstrate that the resistance to both nematodes and tomato powdery mildew in these two NIL is governed by linked (if not the same) Mi-1 homologues in the Mi-1 gene cluster. Finally, we discuss how Solanum crops exploit Mi-1 homologues to defend themselves against distinct pathogens.
authors.affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Center, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands.
authors.forename: Alireza
authors.initials: A
authors.lastname: Seifi
authors.forename: Isgouhi
authors.initials: I
authors.lastname: Kaloshian
authors.forename: Jack
authors.initials: J
authors.lastname: Vossen
authors.forename: Daidi
authors.initials: D
authors.lastname: Che
authors.forename: Kishor K
authors.initials: KK
authors.lastname: Bhattarai
authors.forename: Junmei
authors.initials: J
authors.lastname: Fan
authors.forename: Zabun
authors.initials: Z
authors.lastname: Naher
authors.forename: Aska
authors.initials: A
authors.lastname: Goverse
authors.forename: W Freddy
authors.initials: WF
authors.lastname: Tjallingii
authors.forename: Pim
authors.initials: P
authors.lastname: Lindhout
authors.forename: Richard G F
authors.initials: RG
authors.lastname: Visser
authors.forename: Yuling
authors.initials: Y
authors.lastname: Bai
mesh_terms: D000818:Animals; D001042:Aphids / Q000276:immunology / Q000472:pathogenicity / Q000502:physiology; D001203:Ascomycota / Q000276:immunology* / Q000472:pathogenicity / Q000502:physiology; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D002963:Cladosporium / Q000472:pathogenicity / Q000502:physiology; D017343:Genes, Plant / Q000235:genetics; D008040:Genetic Linkage; D006790:Host-Parasite Interactions; D054884:Host-Pathogen Interactions; D007113:Immunity, Innate / Q000235:genetics; D018551:Solanum lycopersicum / Q000235:genetics* / Q000276:immunology / Q000382:microbiology / Q000469:parasitology; D008969:Molecular Sequence Data; D005810:Multigene Family; D009348:Nematoda / Q000276:immunology* / Q000472:pathogenicity / Q000502:physiology; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000469:parasitology; D057865:Plant Immunity / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics* / Q000502:physiology; D014431:Tylenchoidea / Q000276:immunology / Q000472:pathogenicity / Q000502:physiology
chemical_list: C117349:MI-1 protein, Lycopersicon esculentum; D010940:Plant Proteins