Modelling the Effects of Traits and Abiotic Factors on Viral Lysis in Phytoplankton
Modelling the Effects of Traits and Abiotic Factors on Viral Lysis in Phytoplankton
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DOI：
10.3389/fmars.2021.667184
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发表时间：
2021-05-21
影响因子：
3.7
通讯作者：
Wilson, William H.
中科院分区：
文献类型：
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作者：
Flynn, Kevin J.;Kimmance, Susan A.;Wilson, William H.
建立了溶菌病毒-浮游植物-寄主偶对相互作用的机械系统动力学描述。该模型具有病毒、未感染和感染宿主生物量的状态变量，并描述了病毒和宿主的异速生长和生理。该模型类似于实验实验室病毒-宿主系统，但更适合假设检验，使我们能够探索一些被怀疑影响浮游生物病毒-宿主动力学的鲜为人知的因素的相对重要性。模型行为探讨了非生物因素（光照、混合层深度、营养物质和悬浮颗粒负载）、宿主性状（大小、生长速度、活动性）和病毒性状（大小、潜伏期和爆发大小，包括与受损宿主生理的联系以及衰减率）。模拟表明，病毒的最佳性能（即最佳性状特征）是与病毒、其宿主和环境有关的许多因素的函数。一般来说，较小的病毒和较小的活动宿主会产生更有效的感染结果，从而导致宿主的快速死亡和感染后病毒的高丰度。然而，相互作用发展的时机（宿主种群快速增长开始时宿主病毒的相对丰度）重叠于宿主的生长速度和生理状态，被认为是至关重要的。因此，对于模型的任何一种配置，病毒的接种水平（感染的多重性- moi）显示出一个最佳时间点，介于感染发展过快，限制生物量积累，或太晚，以至于营养或光照限制损害宿主生理，从而导致爆发大小。重要的是，感染的成功还取决于悬浮粒子的负荷，如果悬浮粒子的负荷足够高，就会吸附大量的病毒，从而使感染不会发生。我们得出的结论是，由于单个和耦合的病毒-宿主过程与环境相互作用的方式，以现实的方式将病毒添加到浮游生物生态系统模型中是一个复杂的过程。
A mechanistic system dynamics description is developed of the interactions between a single lytic-virus - phytoplankton-host couple. The model has state variables for virus, uninfected and infected host biomass, and describes virus and host allometry and physiology. The model, analogous to experimental laboratory virus-host systems but more amenable to hypothesis testing, enables us to explore the relative importance of some of the poorly understood factors suspected to impact plankton virus-host dynamics. Model behaviour is explored with respect to abiotic factors (light, mixed layer depth, nutrient and suspended particle loading), host traits (size, growth rate, motility) and virus traits (size, latent period and burst size including linkage to compromised host physiology, and decay rates). Simulations show that the optimal performance of a virus (i.e., optimal trait characterisation) is a function of many factors relating to the virus, its host, and the environment. In general, smaller viruses and smaller motile hosts give rise to more productive infection outcomes that result in rapid demise of the host and high post-infection virus abundance. However, the timing of the development of the interaction (relative abundance of virus to host at the start of rapid host population growth), overlain on the growth rate and physiological status of the host, was seen to be critical. Thus, for any one configuration of the model, the inoculum level of the virus (multiplicity of infection-MOI) displayed an optimum time-point between the infection developing too quickly, limiting biomass accumulation, or too late so that nutrient or light limitation compromised host physiology and hence the burst size. Importantly, the success of an infection depended also upon the suspended particle load which, if high enough, adsorbs so many viruses that the infection does not develop. We conclude that adding viruses to plankton ecosystem models in a realistic fashion is a complicated process due to the way that the individual and coupled virus-host processes interact with the environment.