Hamelin Frédéric M, Allen Linda J S, Prendeville Holly R, Hajimorad M Reza, Jeger Michael J
Department of Ecology, Agrocampus Ouest, UMR1349 IGEPP, F-35042 Rennes, France.
Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409-1042, USA.
J Theor Biol. 2016 May 7;396:75-89. doi: 10.1016/j.jtbi.2016.02.017. Epub 2016 Feb 22.
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.
通过种子、花粉或媒介进行的传播来研究植物病毒传播途径的演变。我们探讨以下问题：在何种情况下媒介传播会使花粉传播变得多余？进化能否导致多种病毒传播途径共存？我们将分析限制在一个必须通过种子繁殖的一年生植物种群中。构建了一个包含花粉、种子和媒介传播的半离散模型来研究这些问题。我们假设媒介传播率和花粉传播率分别依赖于频率和密度。对该半离散模型进行了生态稳定性分析，并用于为花粉和种子与媒介传播之间权衡的进化研究提供信息。进化动态严重依赖于权衡函数的形状。假设花粉和媒介传播之间存在权衡，进化要么导致花粉和媒介传播的进化稳定混合（凹形权衡），要么存在进化双稳性（凸形权衡）；花粉传播的存在可能会阻止媒介传播的进化。考虑种子和媒介传播之间的权衡，进化分支以及随后花粉传播和媒介传播菌株的共存是可能的。本研究为自然界中观察到的植物病毒传播模式多样性背后的理论做出了贡献。
