# Two Novel Betarhabdovirins Infecting Ornamental Plants and the Peculiar Intracellular Behavior of the Cytorhabdovirus in the Liana Aristolochia gibertii

## TL;DR

Two new plant viruses were discovered in Brazil, showing unique behaviors inside host cells and differing transmission methods.

## Contribution

Identification of two novel betarhabdoviruses with distinct intracellular behaviors and genome features.

## Key findings

- AaCV has an additional ORF between P3 and M, encoding a transmembrane helix.
- FaJV accumulates in the perinuclear space and forms electron-lucent viroplasms in nuclei.
- AaCV virions associate with mitochondria or peroxisomes, unlike typical rhabdoviruses.

## Abstract

Two novel members of the subfamily Betarhabdovirinae, family Rhabdoviridae, were identified in Brazil. Overall, their genomes have the typical organization 3′-N-P-P3-M-G-L-5′ observed in mono-segmented plant-infecting rhabdoviruses. In aristolochia-associated cytorhabdovirus (AaCV), found in the liana aristolochia (Aristolochia gibertii Hook), an additional short orphan ORF encoding a transmembrane helix was detected between P3 and M. The AaCV genome and inferred encoded proteins share the highest identity values, consistently < 60%, with their counterparts of the yerba mate chlorosis-associated virus (Cytorhabdovirus flaviyerbamate). The second virus, false jalap virus (FaJV), was detected in the herbaceous plant false jalap (Mirabilis jalapa L.) and represents together with tomato betanucleorhabdovirus 2, originally found in tomato plants in Slovenia, a tentative new species of the genus Betanucleorhabdovirus. FaJV particles accumulate in the perinuclear space, and electron-lucent viroplasms were observed in the nuclei of the infected cells. Notably, distinct from typical rhabdoviruses, most virions of AaCV were observed to be non-enclosed within membrane-bounded cavities. Instead, they were frequently seen in close association with surfaces of mitochondria or peroxisomes. Unlike FaJV, AaCV was successfully graft-transmitted to healthy plants of three species of the genus Aristolochia, while mechanical and seed transmission proved unsuccessful for both viruses. Data suggest that these viruses belong to two new tentative species within the subfamily Betarhabdovirinae.