# Elm Blunervirus 1: A Novel Hexapartite Blunervirus Infecting Ulmus parvifolia in China

## TL;DR

A new blunervirus, ElmBlV1, was discovered infecting elm trees in China, expanding the known diversity of this virus group.

## Contribution

The discovery of ElmBlV1, a novel hexapartite blunervirus infecting Ulmus parvifolia in China, expands the genomic and biological understanding of the Blunervirus genus.

## Key findings

- ElmBlV1 has six RNA segments, including two additional genomic components not previously reported in blunerviruses.
- ElmBlV1 proteins show amino acid identities ranging from 25.9% to 64.2% compared to known blunerviruses.
- Phylogenetic analysis shows ElmBlV1 is most closely related to blueberry necrotic ring blotch virus.

## Abstract

The genus Blunervirus comprises plant viruses that infect a diverse range of plants, but no blunervirus has been reported infecting elm trees (Ulmus parvifolia) in China to date. Using high-throughput sequencing and reverse-transcription PCR assays, a novel blunervirus, tentatively named elm blunervirus 1 (ElmBlV1), was identified from a symptomatic elm plant (Ulmus parvifolia) in China. The genome of ElmBlV1 harbors canonical molecular features of blunerviruses and comprises six RNA segments (RNAs1–6), with RNA5 and 6 being two additional genomic components not reported in known blunerviruses. Sequence analyses revealed amino acid (aa) identity of ElmBlV1 proteins ranging from 25.9% (polyprotein encoded by RNA1) to 64.2% (movement protein encoded by RNA4) relative to reported blunerviruses and include five orphan open reading frames. Phylogenetically, ElmBlV1 is most closely related to blueberry necrotic ring blotch virus. Furthermore, ElmBlV1 P37 localizes to both plasmodesmata and the nucleus. Additionally, the RNA reads mapping revealed high read coverage was observed on RNAs3–4 for this virus. To our knowledge, this is the first report of a blunervirus infecting an elm tree in China. Our results enrich the diversity of known viruses in the genus of Blunervirus and expand our understanding of their genomic characteristics and molecular biology.