title: The wild tomato speciesSolanum chilenseshows variation in pathogen resistance between geographically distinct populations.
abstract: Wild tomatoes are a valuable source of disease resistance germplasm for tomato (Solanum lycopersicum) breeders. Many species are known to possess a certain degree of resistance against certain pathogens; however, evolution of resistance traits is yet poorly understood. For some species, likeSolanum chilense, both differences in habitat and within species genetic diversity are very large. Here we aim to investigate the occurrence of spatially heterogeneous coevolutionary pressures between populations ofS. chilense. We investigate the phenotypic differences in disease resistance withinS. chilenseagainst three common tomato pathogens (Alternaria solani,Phytophthora infestansand aFusarium sp.) and confirm high degrees of variability in resistance properties between selected populations. Using generalised linear mixed models, we show that disease resistance does not follow the known demographic patterns of the species. Models with up to five available climatic and geographic variables are required to best describe resistance differences, confirming the complexity of factors involved in local resistance variation. We confirm that withinS. chilense, resistance properties against various pathogens show a mosaic pattern and do not follow environmental patterns, indicating the strength of local pathogen pressures. Our study can form the basis for further investigations of the genetic traits involved.
authors.affiliation: Section of Population Genetics, Technical University of Munich , Freising , Germany.
authors.forename: Remco
authors.initials: R
authors.lastname: Stam
authors.affiliation: Section of Population Genetics, Technical University of Munich , Freising , Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Scheikl
authors.affiliation: Section of Population Genetics, Technical University of Munich , Freising , Germany.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Tellier
keywords: Alternaria; Fusarium; General liniarised mixed models; Phytopathology; Phytophthora; Wild tomato