A Newly Identified Virus in the Family <i>Potyviridae</i> Encodes Two Leader Cysteine Proteases in Tandem That Evolved Contrasting RNA Silencing Suppression Functions
Qin Li, Wentao Shen, Zhongfa Tang, Weiyao Hu, Lingna Shangguan, Yaodi Wang, Decai Tuo, Zengping Li, Weiguo Miao, Adrián Vallí, Aiming Wang, Hongguang Cui
Abstract
represent the largest group of known plant RNA viruses and account for more than half of the viral crop damage worldwide. The leader proteases of viruses within the family vary greatly in size and arrangement and play key roles during the infection. Here, we experimentally demonstrate the presence of a distinct pattern of leader proteases, HCPro1 and HCPro2 in tandem, in a newly identified member within the family. Moreover, HCPro1 and HCPro2, which are closely related and typically characterized with a short size, have evolved contrasting RNA silencing suppression activity and seem to function in a coordinated manner to maintain viral infectivity. Altogether, the new knowledge fills a missing piece in the evolutionary relationship history of potyvirids and improves our understanding of the diversification of potyvirid genomes.