title: Identification of candidate MLO powdery mildew susceptibility genes in cultivated Solanaceae and functional characterization of tobacco NtMLO1.
abstract: Specific homologs of the plant Mildew Locus O (MLO) gene family act as susceptibility factors towards the powdery mildew (PM) fungal disease, causing significant economic losses in agricultural settings. Thus, in order to obtain PM resistant phenotypes, a general breeding strategy has been proposed, based on the selective inactivation of MLO susceptibility genes across cultivated species. In this study, PCR-based methodologies were used in order to isolate MLO genes from cultivated solanaceous crops that are hosts for PM fungi, namely eggplant, potato and tobacco, which were named SmMLO1, StMLO1 and NtMLO1, respectively. Based on phylogenetic analysis and sequence alignment, these genes were predicted to be orthologs of tomato SlMLO1 and pepper CaMLO2, previously shown to be required for PM pathogenesis. Full-length sequence of the tobacco homolog NtMLO1 was used for a heterologous transgenic complementation assay, resulting in its characterization as a PM susceptibility gene. The same assay showed that a single nucleotide change in a mutated NtMLO1 allele leads to complete gene loss-of-function. Results here presented, also including a complete overview of the tobacco and potato MLO gene families, are valuable to study MLO gene evolution in Solanaceae and for molecular breeding approaches aimed at introducing PM resistance using strategies of reverse genetics.
authors.affiliation: Laboratory of Plant Breeding, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
authors.forename: Michela
authors.initials: M
authors.lastname: Appiano
authors.affiliation: Department of Plant, Soil and Food Science, Section of Genetics and Plant Breeding, University of Bari Aldo Moro, Via Amendola 165/A, 70126, Bari, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pavan
authors.affiliation: Institute of Biosciences and Bioresources, Italian National Research Council, Via Amendola 165/A, 70126, Bari, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Catalano
authors.affiliation: Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, No. 12 Zhongguan Cun Nan Da Jie, Beijing, 100081, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: Department of Plant, Soil and Food Science, Section of Genetics and Plant Breeding, University of Bari Aldo Moro, Via Amendola 165/A, 70126, Bari, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Bracuto
authors.affiliation: Department of Agro-Environmental Science, Chemistry and Crop Protection, University of Foggia, Via Napoli 25, 71100, Foggia, Italy.
authors.forename: Concetta
authors.initials: C
authors.lastname: Lotti
authors.affiliation: Laboratory of Plant Breeding, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
authors.forename: Richard G F
authors.initials: RG
authors.lastname: Visser
authors.affiliation: Department of Plant, Soil and Food Science, Section of Genetics and Plant Breeding, University of Bari Aldo Moro, Via Amendola 165/A, 70126, Bari, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Ricciardi
authors.affiliation: Laboratory of Plant Breeding, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands. bai.yuling@wur.nl.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Bai
mesh_terms: D000595:Amino Acid Sequence; D001203:Ascomycota / Q000472:pathogenicity*; D005656:Fungal Proteins / Q000737:chemistry; D008969:Molecular Sequence Data; D010802:Phylogeny; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D019657:Solanaceae / Q000235:genetics* / Q000382:microbiology; D014026:Nicotiana / Q000235:genetics* / Q000382:microbiology
chemical_list: D005656:Fungal Proteins
keywords: MLO; Plant breeding; Powdery mildew; Resistance; Solanaceae