Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Context‐dependent variability in the population prevalence and individual fitness effects of plant–fungal symbiosis
Journal of Ecology ( IF 5.3 ) Pub Date : 2020-10-09 , DOI: 10.1111/1365-2745.13510 Marion L. Donald 1 , Teresa F. Bohner 2 , Kory M. Kolis 3 , R. Alan Shadow 4 , Jennifer A. Rudgers 5 , Tom E. X. Miller 1
中文翻译：
植物-真菌共生的种群流行率和个体适应性影响的背景依赖性变异
更新日期：2020-10-09
Journal of Ecology ( IF 5.3 ) Pub Date : 2020-10-09 , DOI: 10.1111/1365-2745.13510 Marion L. Donald 1 , Teresa F. Bohner 2 , Kory M. Kolis 3 , R. Alan Shadow 4 , Jennifer A. Rudgers 5 , Tom E. X. Miller 1
Affiliation
|
- Heritable symbionts are often observed at intermediate prevalence within host populations, despite expectations that positive fitness feedbacks should drive beneficial symbionts to fixation. Intermediate prevalence may reflect neutral dynamics of symbionts with weak fitness effects, transient dynamics of symbionts trending towards fixation (or elimination), or a stable intermediate outcome determined by the balance of fitness effects and failed symbiont transmission. Theory suggests that these outcomes should depend on symbiont‐conferred demographic effects and vertical transmission efficiency, which may both depend on environmental context.
- We established experimental populations of winter bent grass Agrostis hyemalis across a range of prevalence of the heritable fungal endophyte Epichloë amarillans. Using irrigation, we elevated the precipitation for half of the populations, which we hypothesized would weaken the benefits of symbiosis. Across two annual transitions, we assayed 5,485 individuals to determine prevalence and censused 954 individuals for demographic (survival, flowering, reproduction and recruitment) and vertical transmission data. We used hierarchical Bayesian models to infer long‐run equilibria from short‐term changes in symbiont prevalence and estimated demographic vital rates to link individual‐level effects to population‐level outcomes.
- We found evidence for all three proposed mechanisms for intermediate symbiont prevalence, but the outcome differed qualitatively across years and precipitation treatments. In the first year, symbionts trended towards fixation under drought conditions but drifted neutrally under elevated precipitation. Fixation likely arose from symbiont‐conferred recruitment benefits outweighing reproductive costs under the drought conditions, while elevated precipitation tempered these effects. In the second transition year, we inferred stable intermediate prevalence across both precipitation treatments, which indicated a balance between symbiont conferred recruitment benefits that allowed low‐prevalence populations to increase and imperfect transmission that caused high‐prevalence populations to decrease.
- Synthesis. We find support for neutral, transient and stable mechanisms underlying symbiont prevalence, indicating that symbiont prevalence is often pushed and pulled in different directions by the composite outcome of symbiont effects on demographic rates and transmission efficiency, and the way in which these processes respond to environmental context.
中文翻译：
植物-真菌共生的种群流行率和个体适应性影响的背景依赖性变异
- 尽管寄希望于积极的适应性反馈应促使有益的共生体凝视，但通常在宿主人群中处于中等流行状态时观察到遗传性共生体。中度患病率可能反映出适应性较弱的共生体的中性动力学，趋向于固定（或消除）的共生体的瞬态动力学或适应性效应和共生体传播失败所决定的稳定的中间结果。理论表明，这些结果应取决于共生赋予的人口效应和垂直传播效率，而这两者都可能取决于环境。
- 我们建立了冬季草弯曲实验种群翦股hyemalis在一系列的遗传性内生真菌的患病率稻香amarillans。通过灌溉，我们提高了一半人口的降水量，我们认为这会削弱共生的好处。在两个年度过渡期中，我们对5,485个人进行了测定以确定流行程度，并针对人口统计（生存，开花，繁殖和募集）和垂直传播数据对954个人进行了普查。我们使用分层贝叶斯模型从共生体患病率的短期变化和估计的人口生命率推断长期均衡，以将个体水平的影响与人口水平的结果联系起来。
- 我们发现了所有三种提议的中间共生体流行机制的证据，但结果在多年和降水处理方面存在质的差异。在第一年，共生体趋向于在干旱条件下固着，但在降水增加时中性地漂移。在干旱条件下，共生物招募带来的收益超过了繁殖成本，而固定的收入则可能产生了固执，而降水量的增加抑制了这些影响。在第二个过渡年中，我们推断两种降水处理之间的中间流行率稳定，这表明共生体赋予的招聘收益之间的平衡，使低流行率人群增加而传播不完善导致高流行率人群减少。
- 综合。我们发现共生体流行背后的中性，短暂和稳定机制的支持，表明共生体流行通常是由共生体对人口率和传播效率的复合结果以及这些过程对环境的反应方式在不同方向上推动和拉动的。上下文。
京公网安备 11010802027423号