title: The evolution of plant virus transmission pathways.
abstract: The evolution of plant virus transmission pathways is studied through transmission via seed, pollen, or a vector. We address the questions: under what circumstances does vector transmission make pollen transmission redundant? Can evolution lead to the coexistence of multiple virus transmission pathways? We restrict the analysis to an annual plant population in which reproduction through seed is obligatory. A semi-discrete model with pollen, seed, and vector transmission is formulated to investigate these questions. We assume vector and pollen transmission rates are frequency-dependent and density-dependent, respectively. An ecological stability analysis is performed for the semi-discrete model and used to inform an evolutionary study of trade-offs between pollen and seed versus vector transmission. Evolutionary dynamics critically depend on the shape of the trade-off functions. Assuming a trade-off between pollen and vector transmission, evolution either leads to an evolutionarily stable mix of pollen and vector transmission (concave trade-off) or there is evolutionary bi-stability (convex trade-off); the presence of pollen transmission may prevent evolution of vector transmission. Considering a trade-off between seed and vector transmission, evolutionary branching and the subsequent coexistence of pollen-borne and vector-borne strains is possible. This study contributes to the theory behind the diversity of plant-virus transmission patterns observed in nature.
authors.affiliation: Department of Ecology, Agrocampus Ouest, UMR1349 IGEPP, F-35042 Rennes, France. Electronic address: fhamelin@agrocampus-ouest.fr.
authors.forename: Frédéric M
authors.initials: FM
authors.lastname: Hamelin
authors.affiliation: Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409-1042, USA.
authors.forename: Linda J S
authors.initials: LJ
authors.lastname: Allen
authors.affiliation: USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331, USA.
authors.forename: Holly R
authors.initials: HR
authors.lastname: Prendeville
authors.affiliation: Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996-4560, USA.
authors.forename: M Reza
authors.initials: MR
authors.lastname: Hajimorad
authors.affiliation: Division of Ecology and Evolution, Centre for Environmental Policy, Imperial College London, SL5 7PY, UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Jeger
mesh_terms: D019143:Evolution, Molecular; D008954:Models, Biological; D010935:Plant Diseases / Q000821:virology*; D010942:Plant Viruses / Q000502:physiology*
keywords: Adaptive dynamics; Density-dependent; Evolutionary bi-stability; Evolutionary branching; Frequency-dependent; Horizontal; Pollen; Seed; Vector; Vertical