Tuberculina species are mitosporic parasites of rust fungi. It was demonstrated recently that Tuberculina represents the asexual life stage of the plant-parasitic genus Helicobasidium. Here we reveal the host specificities of Tuberculina and Helicobasidium species on rust fungal hosts by means of infection experiments and molecular analyses. We inoculated species of the rust genera Chrysomyxa, ...

Although disease-resistance polymorphisms are common in natural plant populations, the mechanisms responsible for this variation are not well understood. Theoretical models predict that balancing selection can maintain polymorphism within a population if the fitness effects of a resistance allele vary from a net cost to a net benefit, depending upon the extent of pathogen damage. However, there...

The genetic basis of resistance to pathogens is well studied in crops, yet our understanding of the evolution of this trait in natural populations will be improved by determining how resistance is inherited in a wide range of plant-pathogen interactions. Here, we examined resistance to Coleosporium ipomoeae, a common fungal rust pathogen of Ipomoea purpurea. Natural populations across North Car...

• The strength and consistency of genotypic differences in disease resistance determine the potential for resistance evolution in host populations that rely on vegetative reproduction. Here we surveyed infection intensity of host genotypes across space and time to estimate genotypic and environmental effects on quantitative disease resistance. • Cloned fragments of 12 Euthamia graminifolia geno...

Variation in the environment is common within and between natural populations and may influence selection on plant resistance by altering the level of damage or the fitness consequences of damage from plant enemies. While much is known about how environmental variation influences the amount of damage a plant experiences, few studies have attempted to determine how variation in the environment m...