Occurrence and Distribution of <i>Actinidia</i> Viruses in Shaanxi Province of China

Abstract

Kiwifruit (<i>Actinidia</i> spp.) is an economically important fruit crop globally. China is the largest kiwifruit-growing country in the world, and Shaanxi Province is the major kiwifruit-growing region in China. A systematic survey detected various symptoms in kiwifruit plants grown in a commercial kiwifruit field in Shaanxi Province. Samples were collected from kiwifruit plants showing symptoms and used for virus detection by high-throughput sequencing. In addition to 10 known kiwifruit viruses, three new viruses were detected and tentatively named Actinidia yellowing ringspot virus (AYRSpV), Actinidia yellowing virus 1 (AcYV1), and Actinidia yellowing virus 2 (AcYV2). The genome sequences of the three new viruses and four known viruses were determined. Based on the demarcation criteria of the International Committee on Taxonomy of Viruses, AYRSpV might be a new member of the genus <i>Ilarvirus</i> in the family <i>Bromoviridae</i>, AcYV1 might be a new virus of the genus <i>Waikavirus</i> in the family <i>Secoviridae</i>, and AcYV2 might be a novel virus in the family <i>Tombusviridae</i>. Spherical viral particles were found in the samples infected with AYRSpV, AcYV1, and AcYV2 by transmission electron microscopy. Further analysis showed that all 13 viruses can infect both <i>Actinidia deliciosa</i> and <i>A. chinensis</i> but the incidences of these infections vary among different kiwifruit cultivars in different regions. These results provide valuable information for understanding the virome of kiwifruit in China.