Ubiquitin-Conjugating Enzyme E2 E Inhibits the Accumulation of Rice Stripe Virus in Laodelphax striatellus (Fallén)

Abstract

The ubiquitin-proteasome system (UPS) is an essential protagonist in host-pathogen interactions. Among the three classes of enzymes in the UPS, ubiquitin-conjugating enzyme E2 plays a dual role in viral pathogenesis; however, the role of insect E2s in interactions with plant viruses is unclear. Twenty E2-encoding genes in <i>Laodelphax striatellus</i>, the small brown planthopper, were identified and classified into 17 groups by transcriptomic and phylogenetic analysis. Full-length cDNAs of four <i>LstrE2s</i> (<i>LstrE2 A/E/G2/H</i>) were obtained by rapid-amplification of cDNA ends (RACE-PCR) analysis. Expression of the four <i>LstrE2s</i> showed tissue- and development-specific patterns. RT-qPCR analyses revealed that Rice stripe viruse (RSV) infection increased the level of <i>LstrE2 A/E/G2/H</i>. Further study indicated that repression of <i>LstrE2 E</i> via RNAi caused significant increases in the expression of RSV coat protein mRNA and protein levels. These findings suggest that LstrE2 E inhibits RSV accumulation in the planthopper body. Understanding the function of LstrE2 E in RSV accumulation may ultimately result in the development of novel antiviral strategies.