title: Pea powdery mildew er1 resistance is associated to loss-of-function mutations at a MLO homologous locus.
abstract: The powdery mildew disease affects several crop species and is also one of the major threats for pea (Pisum sativum L.) cultivation all over the world. The recessive gene er1, first described over 60 years ago, is well known in pea breeding, as it still maintains its efficiency as a powdery mildew resistance source. Genetic and phytopathological features of er1 resistance are similar to those of barley, Arabidopsis, and tomato mlo powdery mildew resistance, which is caused by the loss of function of specific members of the MLO gene family. Here, we describe the obtainment of a novel er1 resistant line by experimental mutagenesis with the alkylating agent diethyl sulfate. This line was found to carry a single nucleotide polymorphism in the PsMLO1 gene sequence, predicted to result in premature termination of translation and a non-functional protein. A cleaved amplified polymorphic sequence (CAPS) marker was developed on the mutation site and shown to be fully co-segregating with resistance in F(2) individuals. Sequencing of PsMLO1 from three powdery mildew resistant cultivars also revealed the presence of loss-of-function mutations. Taken together, results reported in this study strongly indicate the identity between er1 and mlo resistances and are expected to be of great breeding importance for the development of resistant cultivars via marker-assisted selection.
authors.affiliation: Department of Agroforestry, Environmental Biology and Chemistry, Section of Genetics and Plant Breeding, University of Bari, Via Amendola 165/A, 70126 Bari, Italy. stefano.pavan@agr.uniba.it
authors.forename: Stefano
authors.initials: S
authors.lastname: Pavan
authors.forename: Adalgisa
authors.initials: A
authors.lastname: Schiavulli
authors.forename: Michela
authors.initials: M
authors.lastname: Appiano
authors.forename: Angelo R
authors.initials: AR
authors.lastname: Marcotrigiano
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Cillo
authors.forename: Richard G F
authors.initials: RG
authors.lastname: Visser
authors.forename: Yuling
authors.initials: Y
authors.lastname: Bai
authors.forename: Concetta
authors.initials: C
authors.lastname: Lotti
authors.forename: Luigi
authors.initials: L
authors.lastname: Ricciardi
mesh_terms: D000595:Amino Acid Sequence; D001203:Ascomycota / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant / Q000235:genetics*; D056426:Genetic Loci / Q000235:genetics*; D005838:Genotype; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D018532:Pisum sativum / Q000235:genetics* / Q000276:immunology / Q000382:microbiology*; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D010940:Plant Proteins