Viral infections are a major factor in diatom cell death. However, the effects of viruses on diatom dynamics remain unclear. Based on laboratory studies, it is hypothesized that virus-induced diatom mortality is dependent on the diatom growth rate. The present study aimed to elucidate the relationship between the diatom growth rate and virus-induced mortality using model systems of the marine planktonic diatom, Chaetoceros tenuissimus and its infectious viruses. We also examined the fate of diatom populations in a semi-continuous dilution culture system, in which host growth rates were controlled at 0.69, 2.08, and 3.47 day-1. Diatom populations gradually decreased following the viral inoculation of each culture system, and virus-induced mortality inversely correlated with the diatom growth rate. Furthermore, the viral burst size was slightly higher in lower growth rate cultures. These results suggested that the host physiological status related to the growth rate affected viral infection and proliferation. Diatom populations were not completely lysed or washed out in any of the dilution systems; they showed steady growth in the presence of infectious viruses. This may be partially explained by defective interference particles from viruses and cell debris. The present results indicate that diatoms in dilution environments maintain their populations, even under viral pressure. Moreover, diatom populations with a low growth rate may partially sustain higher growth populations through nutrient recycling following virus-induced cell death. The results of the present study provide insights into diatom dynamics in natural environments in the presence of infectious viruses.

中文翻译：

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病毒感染导致的硅藻生长速率依赖性细胞死亡及其在半连续培养系统中的后续共存

病毒感染是硅藻细胞死亡的主要因素。然而，病毒对硅藻动力学的影响仍不清楚。根据实验室研究，假设病毒引起的硅藻死亡率取决于硅藻的生长速度。本研究旨在利用海洋浮游硅藻、细角角藻及其传染性病毒的模型系统阐明硅藻生长速率与病毒引起的死亡率之间的关系。我们还检查了半连续稀释培养系统中硅藻种群的命运，其中宿主生长率控制在 0.69、2.08 和 3.47 天-1。在每个培养系统接种病毒后，硅藻种群逐渐减少，病毒引起的死亡率与硅藻生长速度呈负相关。此外，在低增长率培养物中病毒爆发的大小略高。这些结果表明与生长速率相关的宿主生理状态影响病毒感染和增殖。在任何稀释系统中，硅藻种群都没有被完全溶解或洗掉；它们在存在传染性病毒的情况下表现出稳定增长。这可能部分由来自病毒和细胞碎片的有缺陷的干扰粒子来解释。目前的结果表明，即使在病毒压力下，稀释环境中的硅藻也能保持其种群数量。此外，低生长率的硅藻种群可能通过病毒诱导细胞死亡后的养分循环来部分维持较高的生长种群。