KEY MESSAGE: Rphq2, a minor gene for partial resistance to Puccinia hordei , was physically mapped in a 188 kbp introgression with suppressed recombination between haplotypes of rphq2 and Rphq2 barley cultivars. ABSTRACT: Partial and non-host resistances to rust fungi in barley (Hordeum vulgare) may be based on pathogen-associated molecular pattern (PAMP)-triggered immunity. Understanding partial resistance may help to understand non-host resistance, and vice versa. We constructed two non-gridded BAC libraries from cultivar Vada and line SusPtrit. Vada is immune to non-adapted Puccinia rust fungi, and partially resistant to P. hordei. SusPtrit is susceptible to several non-adapted rust fungi, and has been used for mapping QTLs for non-host and partial resistance. The BAC libraries help to identify genes determining the natural variation for partial and non-host resistances of barley to rust fungi. A major-effect QTL, Rphq2, for partial resistance to P. hordei was mapped in a complete Vada and an incomplete SusPtrit contig. The physical distance between the markers flanking Rphq2 was 195 Kbp in Vada and at least 226 Kbp in SusPtrit. This marker interval was predicted to contain 12 genes in either accession, of which only five genes were in common. The haplotypes represented by Vada and SusPtrit were found in 57 and 43%, respectively, of a 194 barley accessions panel. The lack of homology between the two haplotypes probably explains the suppression of recombination in the Rphq2 area and limit further genetic resolution in fine mapping. The possible candidate genes for Rphq2 encode peroxidases, kinases and a member of seven-in-absentia protein family. This result suggests that Rphq2 does not belong to the NB-LRR gene family and does not resemble any of the partial resistance genes cloned previously.

INRA UMR1095 Genetics Diversity and Ecophysiology of Cereals 63039 Clermont Ferrand France Université Blaise Pascal UMR1095 Genetics Diversity and Ecophysiology of Cereals 63039 Clermont Ferrand France

INRA UMR1165 Unité de Recherche en Génomique Végétale 91057 Evry France Université d'Evry Val d'Essonne UMR1165 Unité de Recherche en Génomique Végétale 91057 Evry France

Key Laboratory of Plant Molecular Physiology Institute of Botany Chinese Academy of Sciences Nanxincun 20 Fragrant Hill Beijing 100093 China

Laboratory of Plant Breeding Wageningen University Droevendaalsesteeg 1 6708PB 6700 AJ Wageningen The Netherlands

Laboratory of Plant Breeding Wageningen University Droevendaalsesteeg 1 6708PB 6700 AJ Wageningen The Netherlands Department of Plant Science and Environmental Ecology Faculty of Resource Science and Technology University Malaysia Sarawak 94300 Kota Samarahan Sarawak Malaysia

Laboratory of Plant Breeding Wageningen University Droevendaalsesteeg 1 6708PB 6700 AJ Wageningen The Netherlands INRA UMR1290 BIOGER 78850 Thiverval Grignon France AgroParisTech UMR1290 BIOGER 78850 Thiverval Grignon France

Laboratory of Plant Breeding Wageningen University Droevendaalsesteeg 1 6708PB 6700 AJ Wageningen The Netherlands The Institute of Botany of the Academy of Science of the Czech Republic Zámek 1 252 43 Průhonice Czech Republic

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