Isolate specificity of quantitative trait loci for partial resistance of barley to Puccinia hordei confirmed in mapping populations and near-isogenic lines.
Partial resistance is considered race-nonspecific and durable, consistent with the concept of 'horizontal' resistance. However, detailed observations of partial resistance to leaf rust (Puccinia hordei) in barley (Hordeum vulgare) revealed small cultivar x isolate interactions, suggesting a minor-gene-for-minor-gene interaction model, similar to so-called 'vertical' resistance. Three consistent quantitative trait loci (QTLs), labelled Rphq2, Rphq3 and Rphq4, that were detected in the cross susceptible L94 x partially resistant Vada have been incorporated into the L94 background to obtain near-isogenic lines (NILs). Three isolates were used to map QTLs on seedlings of the L94 x Vada population and to evaluate the effect of each QTL on adult plants of the respective NILs under field conditions. Rphq2 had a strong effect in seedlings but almost no effect in adult plants, while Rphq3 was effective in seedlings and in adult plants against all three isolates. However, Rphq4 was effective in seedlings and in adult plants against two isolates but ineffective in both development stages against the third, demonstrating a clear and reproducible isolate-specific effect. The resistance governed by the three QTLs was not associated with a hypersensitive reaction. Those results confirm the minor-gene-for-minor-gene model suggesting specific interactions between QTLs for partial resistance and P. hordei isolates.
Marcel
Thierry C
TC
Laboratory of Plant Breeding, Graduate School for Experimental Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
Gorguet
Benoît
B
Laboratory of Plant Breeding, Graduate School for Experimental Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
Ta
Minh Truong
MT
Laboratory of Plant Breeding, Graduate School for Experimental Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
Kohutova
Zuzana
Z
Department of Genetics and Breeding, Faculty of Agrobiology, Food and Nature Resourses, Czech University of Agriculture, Prague, Czech Republic.
Vels
Anton
A
Laboratory of Plant Breeding, Graduate School for Experimental Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
Niks
Rients E
RE
Laboratory of Plant Breeding, Graduate School for Experimental Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
D001487:Basidiomycota / Q000276:immunology*; D001467:Hordeum / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000276:immunology*; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D040641:Quantitative Trait Loci; D036226:Seedlings / Q000382:microbiology; D013045:Species Specificity