title: Genetic analysis of durable resistance to Magnaporthe oryzae in the rice accession Gigante Vercelli identified two blast resistance loci.
abstract: Rice cultivars exhibiting durable resistance to blast, the most important rice fungal disease provoking up to 30 % of rice losses, are very rare and searching for sources of such a resistance represents a priority for rice-breeding programs. To this aim we analyzed Gigante Vercelli (GV) and Vialone Nano (VN), two temperate japonica rice cultivars in Italy displaying contrasting response to blast, with GV showing a durable and broad-spectrum resistance, whereas VN being highly susceptible. An SSR-based genetic map developed using a GV × VN population segregating for blast resistance identified two blast resistance loci, localized to the long arm of chromosomes 1 and 4 explaining more than 78 % of the observed phenotypic variation for blast resistance. The pyramiding of two blast resistance QTLs was therefore involved in the observed durable resistance in GV. Mapping data were integrated with information obtained from RNA-seq expression profiling of all classes of resistance protein genes (resistance gene analogs, RGAs) and with the map position of known cloned or mapped blast resistance genes to search candidates for the GV resistant response. A co-localization of RGAs with the LOD peak or the marker interval of the chromosome 1 QTL was highlighted and a valuable tool for selecting the resistance gene during breeding programs was developed. Comparative analysis with known blast resistance genes revealed co-positional relationships between the chromosome 1 QTL with the Pi35/Pish blast resistance alleles and showed that the chromosome 4 QTL represents a newly identified blast resistance gene. The present genetic analysis has therefore allowed the identification of two blast resistance loci in the durable blast-resistant rice cultivar GV and tools for molecular selection of these resistance genes.
authors.affiliation: Council for Agricultural Research and Economics (CRA), Genomics Research Centre, Via S. Protaso, 302, 29017, Fiorenzuola d'Arda, Piacenza, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Urso
authors.affiliation: Council for Agricultural Research and Economics (CRA), Genomics Research Centre, Via S. Protaso, 302, 29017, Fiorenzuola d'Arda, Piacenza, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Desiderio
authors.affiliation: Council for Agricultural Research and Economics (CRA), Genomics Research Centre, Via S. Protaso, 302, 29017, Fiorenzuola d'Arda, Piacenza, Italy.|Council for Agricultural Research and Economics (CRA), Rice Research Unit, S.S. 11 to Torino, Km 2,5, 13100, Vercelli, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Biselli
authors.affiliation: Council for Agricultural Research and Economics (CRA), Genomics Research Centre, Via S. Protaso, 302, 29017, Fiorenzuola d'Arda, Piacenza, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bagnaresi
authors.affiliation: Rice Genomics Group, Parco Tecnologico Padano, Via Einstein, 26900, Lodi, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Crispino
authors.affiliation: Rice Genomics Group, Parco Tecnologico Padano, Via Einstein, 26900, Lodi, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Piffanelli
authors.affiliation: Rice Genomics Group, Parco Tecnologico Padano, Via Einstein, 26900, Lodi, Italy.
authors.forename: Pamela
authors.initials: P
authors.lastname: Abbruscato
authors.affiliation: Council for Agricultural Research and Economics (CRA), Genomics Research Centre, Via S. Protaso, 302, 29017, Fiorenzuola d'Arda, Piacenza, Italy.|Plant Biochemistry, Institute of Agricultural Sciences, ETH Zürich, LFW D 38 Universitätstrasse 2, 8092, Zurich, Switzerland.
authors.forename: Federica
authors.initials: F
authors.lastname: Assenza
authors.affiliation: Council for Agricultural Research and Economics (CRA), Genomics Research Centre, Via S. Protaso, 302, 29017, Fiorenzuola d'Arda, Piacenza, Italy.|Continental Semences S.p.A., via Monzato 9, 43029, Traversetolo, PR, Italy.
authors.forename: Giada
authors.initials: G
authors.lastname: Guarnieri
authors.affiliation: Council for Agricultural Research and Economics (CRA), Genomics Research Centre, Via S. Protaso, 302, 29017, Fiorenzuola d'Arda, Piacenza, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Cattivelli
authors.affiliation: Council for Agricultural Research and Economics (CRA), Genomics Research Centre, Via S. Protaso, 302, 29017, Fiorenzuola d'Arda, Piacenza, Italy. giampiero.vale@entecra.it.|Council for Agricultural Research and Economics (CRA), Rice Research Unit, S.S. 11 to Torino, Km 2,5, 13100, Vercelli, Italy. giampiero.vale@entecra.it.
authors.forename: Giampiero
authors.initials: G
authors.lastname: Valè
mesh_terms: D000483:Alleles; D001947:Breeding / Q000379:methods; D002874:Chromosome Mapping / Q000379:methods; D060467:Disease Resistance / Q000235:genetics*; D005820:Genetic Testing / Q000379:methods; D020082:Magnaporthe / Q000472:pathogenicity*; D012275:Oryza / Q000235:genetics* / Q000382:microbiology*; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology*; D010940:Plant Proteins / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics*
chemical_list: D010940:Plant Proteins
keywords: Blast disease; Candidate genes; Durable resistance; Genetic mapping; NB-LRR; RNA-seq; Rice