# Inhibition of Rice Stripe Virus Accumulation by Polyubiquitin-C in Laodelphax striatellus

## TL;DR

This study shows that a gene called LsUBC in a type of insect helps prevent a virus from multiplying, suggesting a new role for the ubiquitin system in insect immunity.

## Contribution

The study identifies the role of polyubiquitin-C in inhibiting Rice Stripe Virus accumulation in Laodelphax striatellus for the first time.

## Key findings

- LsUBC is highly expressed in salivary glands, midgut, and reproductive systems of Laodelphax striatellus.
- RSV infection increases LsUBC expression, and reducing LsUBC leads to higher RSV accumulation.
- LsUBC is ubiquitously expressed across developmental stages and is most active in female adults.

## Abstract

The ubiquitin system plays an important role in defense against viruses. In this study, we cloned and characterized the polyubiquitin-C (UBC) gene in Laodelphax striatellus. Expression profile analysis showed that LsUBC was highly expressed in the salivary glands, midgut, and reproductive system. Moreover, the expression of LsUBC was upregulated during viral infection, and inhibition of LsUBC expression increased viral accumulation. These results indicated that LsUBC plays a vital role in inhibiting viral accumulation in L. striatellus.

Many hosts utilize the ubiquitin system to defend against viral infection. As a key subunit of the ubiquitin system, the role of polyubiquitin in the viral infection of insects is unclear. Here, we identified the full-length cDNA of the polyubiquitin-C (UBC) gene in Laodelphax striatellus, the small brown planthopper (SBPH). LsUBC was expressed in various tissues and was highly expressed in salivary glands, midgut, and reproductive systems. Furthermore, the LsUBC expression profiles in the developmental stages showed that LsUBC was ubiquitously expressed in seven developmental stages and was highest expressed in female adults with SBPH. qRT-PCR analyses indicated that rice stripe virus (RSV) infection promoted the LsUBC expression. Knockdown of LsUBC mRNA via RNA interference increased RSV accumulation. These findings suggest that LsUBC inhibits RSV accumulation in L. striatellus.