West Nile virus (WNV, Flaviviridae, Flavivirus) is a mosquito-borne flavivirus introduced to North America in 1999. Since 1999, the Earth’s average temperature has increased by 0.6 °C. Mosquitoes are ectothermic organisms, reliant on environmental heat sources. Temperature impacts vector–virus interactions which directly influence arbovirus transmission. RNA viral replication is highly error-prone and increasing temperature could further increase replication rates, mutation frequencies, and evolutionary rates. The impact of temperature on arbovirus evolutionary trajectories and fitness landscapes has yet to be sufficiently studied. To investigate how temperature impacts the rate and extent of WNV evolution in mosquito cells, WNV was experimentally passaged 12 times in Culex tarsalis cells, at 25 °C and 30 °C. Full-genome deep sequencing was used to compare genetic signatures during passage, and replicative fitness was evaluated before and after passage at each temperature. Our results suggest adaptive potential at both temperatures, with unique temperature-dependent and lineage-specific genetic signatures. Further, higher temperature passage was associated with significantly increased replicative fitness at both temperatures and increases in nonsynonymous mutations. Together, these data indicate that if similar selective pressures exist in natural systems, increases in temperature could accelerate emergence of high-fitness strains with greater phenotypic plasticity.

中文翻译：

---

高温下西尼罗病毒的实验进化促进了广泛的适应和增加的遗传多样性

西尼罗河病毒（WNV，Flaviviridae，Flavivirus）是一种蚊媒黄病毒，于1999年传入北美。自1999年以来，地球平均温度升高了0.6°C。蚊子是变温生物，依赖环境热源。温度影响直接影响虫媒病毒传播的载体-病毒相互作用。RNA 病毒复制非常容易出错，温度升高可能会进一步提高复制率、突变频率和进化率。温度对虫媒病毒进化轨迹和适应性景观的影响尚未得到充分研究。为了研究温度如何影响蚊子细胞中 WNV 进化的速率和程度，WNV 在Culex tarsalis中进行了 12 次实验传代细胞，在 25 °C 和 30 °C。全基因组深度测序用于比较传代过程中的遗传特征，并在每个温度下评估传代前后的复制适应性。我们的结果表明两种温度下的适应性潜力，具有独特的温度依赖性和谱系特异性遗传特征。此外，更高的温度通道与两种温度下的复制适应性显着增加和非同义突变的增加有关。总之，这些数据表明，如果自然系统中存在类似的选择压力，温度升高可能会加速具有更大表型可塑性的高适应性菌株的出现。