UBA1 and infection: It has been reported that V2 protein of Tomato yellow leaf curl Sardinia virus (TYLCSV) interacts with UBA1, a ubiquitin-activating enzyme, which is a positive regulator of plant defense [50, 51], and silencing of either UBA1 or RHF2a (RING-type E3 ubiquitin ligase) in N. benthamiana enhances TYLCSV infection [50, 52].