Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Rensselaer, NY 12144, USA.
The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA.
Viruses. 2021 Sep 22;13(10):1889. doi: 10.3390/v13101889.
West Nile virus (WNV, , 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 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.
西尼罗河病毒（WNV，黄病毒科）是一种通过蚊子传播的黄病毒，于 1999 年传入北美洲。自 1999 年以来，地球平均气温上升了 0.6°C。蚊子是变温动物，依赖环境热源。温度会影响媒介-病毒相互作用，从而直接影响虫媒病毒的传播。RNA 病毒的复制高度易错，并且温度升高可能会进一步增加复制率、突变频率和进化率。温度对虫媒病毒进化轨迹和适应景观的影响尚未得到充分研究。为了研究温度如何影响蚊细胞中 WNV 的进化速度和程度，我们在 25°C 和 30°C 下将 WNV 在 细胞中进行了 12 次实验传代。我们使用全基因组深度测序来比较传代过程中的遗传特征，并在每个温度下传代前后评估复制适应性。我们的结果表明，在两种温度下都存在适应潜力，具有独特的温度依赖性和谱系特异性遗传特征。此外，高温传代会导致在两种温度下的复制适应性显著增加，并增加非同义突变。综上所述，如果在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高表型可塑性的高适应性菌株的出现。
