EVIDENCE FOR MAINTENANCE OF SEX BY PATHOGENS IN PLANTS
Article first published online: 9 MAY 2007
Volume 58, Issue 11, pages 2584–2590, November 2004
How to Cite
Busch, J. W., Neiman, M. and Koslow, J. M. (2004), EVIDENCE FOR MAINTENANCE OF SEX BY PATHOGENS IN PLANTS. Evolution, 58: 2584–2590. doi: 10.1111/j.0014-3820.2004.tb00886.x
- Issue published online: 9 MAY 2007
- Article first published online: 9 MAY 2007
- Received March 4, 2004, Accepted August 25, 2004.
- mating system;
- sexual reproduction
Abstract The predominance of outcrossing despite the substantial transmission advantage of self-fertilization remains a paradox. Theory suggests that selection can favor outcrossing if it enables the production of offspring that are less susceptible to pathogen attack than offspring produced via self-fertilization. Thus, if pathogen pressure is contributing to the maintenance of outcrossing in plants, there may be a positive correlation between the number of pathogen species attacking plant species and the outcrossing rate of the plant species. We tested this hypothesis by examining the association between outcrossing rate and the number of fungal pathogen species that attack a large, taxonomically diverse set of seed plants. We show that plant species attacked by more fungal pathogen species have higher outcrossing rates than plants with fewer enemies. This relationship persists after correcting for study bias among natural and agricultural species of plants. We also accounted for the nested hierarchy of relationships among plant lineages by conducting phylogenetically independent contrasts (PICs) within genera and families that were adequately represented in our dataset. A meta-analysis of the correlation between pathogen and outcrossing PICs shows that there is a positive correlation between pathogen species number and outcrossing rates. This pattern is consistent with the hypothesis that pathogen-mediated selection may contribute to the maintenance of outcrossing in species of seed plants.