Interactions among co-infecting pathogens are common across host taxa and can affect infectious disease dynamics. Host nutrition can mediate these among-pathogen interactions, altering the establishment and growth of pathogens within hosts. It is unclear, however, how nutrition-mediated among-pathogen interactions affect transmission and the spread of disease through populations. We manipulated the nitrogen (N) and phosphorus (P) supplies to oat plants in growth chambers and evaluated interactions between two aphid-vectored Barley and Cereal Yellow Dwarf Viruses: PAV and RPV. We quantified the effect of each virus on the other's establishment, within-plant density, and transmission. Co-inoculation significantly increased PAV density when N and P supplies were low and tended to increase RPV density when N supply was high. Co-infection increased PAV transmission when N and P supplies were low and tended to increase RPV transmission when N supply was high. Despite the parallels between the effects of among-pathogen interactions on density and transmission, changes in virus density only partially explained changes in transmission, suggesting that virus density-independent processes contribute to transmission. A mathematical model describing the spread of two viruses through a plant population, parameterized with empirically derived transmission values, demonstrated that nutrition-mediated among-pathogen interactions could affect disease spread. Interactions that altered transmission through virus density-independent processes determined overall disease dynamics. Our work suggests that host nutrition alters disease spread through among-pathogen interactions that modify transmission.

中文翻译：

---

宿主营养介导植物病毒之间的相互作用，改变传播和预测的疾病传播

共感染病原体之间的相互作用在宿主分类群中很常见，并且会影响传染病动态。宿主营养可以调节病原体间的这些相互作用，改变宿主内病原体的建立和生长。然而，尚不清楚营养介导的病原体间相互作用如何影响疾病在人群中的传播和传播。我们操纵了生长室中燕麦植物的氮 (N) 和磷 (P) 供应，并评估了两种以蚜虫为载体的大麦和谷物黄矮病毒之间的相互作用：PAV 和 RPV。我们量化了每种病毒对另一种病毒的建立、植物内密度和传播的影响。当 N 和 P 供应量低时，共接种显着增加 PAV 密度，当 N 供应量高时，往往会增加 RPV 密度。当 N 和 P 供应量低时，共感染会增加 PAV 传播，而当 N 供应量高时，会增加 RPV 传播。尽管病原体间相互作用对密度和传播的影响之间存在相似性，但病毒密度的变化仅部分解释了传播的变化，这表明与病毒密度无关的过程有助于传播。描述两种病毒在植物种群中传播的数学模型，用经验得出的传播值进行参数化，证明营养介导的病原体间相互作用可能影响疾病传播。通过与病毒密度无关的过程改变传播的相互作用决定了整体疾病动态。