title: Genetic structure and local adaptation of European wheat yellow rust populations: the role of temperature-specific adaptation.
abstract: Environmental heterogeneity influences coevolution and local adaptation in host-parasite systems. This also concerns applied issues, because the geographic range of parasites may depend on their capacity to adapt to abiotic conditions. We studied temperature-specific adaptation in the wheat yellow/stripe rust pathogen, Puccinia striiformis f.sp. tritici (PST). Using laboratory experiments, PST isolates from northern and southern France were studied for their ability to germinate and to infect bread and durum wheat cultivars over a temperature gradient. Pathogen origin × temperature interactions for infectivity and germination rate suggest local adaptation to high- versus low-temperature regimes in south and north. Competition experiments in southern and northern field sites showed a general competitive advantage of southern over northern isolates. This advantage was particularly pronounced in the southern 'home' site, consistent with a model integrating laboratory infectivity and field temperature variation. The stable PST population structure in France likely reflects adaptation to ecological and genetic factors: persistence of southern PST may be due to adaptation to the warmer Mediterranean climate; and persistence of northern PST can be explained by adaptation to commonly used cultivars, for which southern isolates are lacking the relevant virulence genes. Thus, understanding the role of temperature-specific adaptations may help to improve forecast models or breeding programmes.
authors.affiliation: UR BIOGER CPP, INRA Agro-Paris-Tech Thiverval-Grignon, France ; LMU Biocenter, Section of Evolutionary Biology, Grosshaderner Strasse Planegg-Martinsried, Germany.
authors.forename: Mamadou
authors.initials: M
authors.lastname: Mboup
authors.affiliation: UR BIOGER CPP, INRA Agro-Paris-Tech Thiverval-Grignon, France.
authors.forename: Bochra
authors.initials: B
authors.lastname: Bahri
authors.affiliation: UR BIOGER CPP, INRA Agro-Paris-Tech Thiverval-Grignon, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Leconte
authors.affiliation: UR BIOGER CPP, INRA Agro-Paris-Tech Thiverval-Grignon, France.
authors.forename: Claude
authors.initials: C
authors.lastname: De Vallavieille-Pope
authors.affiliation: Institut des Sciences de l'Evolution (ISEM), UMR 5554 (CC065), Université Montpellier 2 Place Eugéne Bataillon, Montpellier Cedex, France.
authors.forename: Oliver
authors.initials: O
authors.lastname: Kaltz
authors.affiliation: Inra, UMR de Génétique Végétale, CNRS université Paris-Sud AgroParisTech ferme du Moulon, Gif-sur-Yvette, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Enjalbert
keywords: Puccinia striiformis f.sp. tritici; climate change; genotype × environment interaction; local adaptation; plant pathogen; temperature adaptation; wheat; yellow/stripe rust