Alfalfa (Medicago sativa L.) growing areas of Argentina were surveyed between 2010 and 2018 to determine the geographical distribution and analyse the genetic diversity among alfalfa enamovirus-1 (AEV-1) isolates. The virus was detected in all 17 surveyed alfalfa-producing provinces, with a prevalence of 64%. The plant virus AEV-1 is widely distributed in the country, and its transmission vector has been unknown until now. Here we show that the black aphid Aphis craccivora can transmit AEV-1. The CP sequence identity among 16 AEV-1 isolates from Argentina was from 98 to 100% and from 98.9 to 100% at nucleotide and amino acid levels, respectively, indicating a low level of sequence variation among these isolates. The phylogenetic analysis based on the complete nucleotide sequence of the CP gene indicated that AEV-1 isolates are closely related and clustered in a monophyletic group. These results suggest that AEV-1 has spread very recently in Argentina. In the present study, we report the geographical distribution of AEV-1 in the main alfalfa-growing areas of Argentina and, for the first time, identify an insect vector and describe the CP gene diversity of an enamovirus worldwide.

在2010年至2018年之间对阿根廷的苜蓿（苜蓿（Medicago sativa L.）在所有接受调查的17个苜蓿生产省中都检测到了该病毒，其流行率为64％。植物病毒AEV-1在该国广泛分布，其传播媒介至今仍未知。在这里，我们显示了黑色蚜虫Aphis craccivora可以传送AEV-1。在阿根廷的16个AEV-1分离株中，CP序列同一性在核苷酸和氨基酸水平上分别为98％至100％和98.9％至100％，表明这些分离株之间的序列变异水平较低。基于CP基因完整核苷酸序列的系统进化分析表明，AEV-1分离株密切相关，并聚集在一个单系统群体中。这些结果表明，AEV-1最近在阿根廷传播了。在本研究中，我们报告了AEV-1在阿根廷主要苜蓿种植地区的地理分布，并且首次确定了昆虫载体，并描述了全世界的一种Enamovirus的CP基因多样性。