Caracterização molecular de mitovirus associados a maracujazeiros (Passiflora Spp.).

Abstract

Mitoviruses consist of a group of ssRNA (+) viruses with a single ORF encoding a viral RNA-dependent RNA Polymerase (RdRp) protein and have no capsid. These viruses belong to the Mitoviridae family, infect mitochondria of phytopathogenic fungi, and were recently detected infecting plants. Although a DNA stage in the replication cycle or genome integration is not required, mitovirus-derived sequences can be detected in

host mitochondrial and nuclear genomes of plants. In some cases, these mitovirus- derived sequences are capable of being transcribed. Passion fruit (Passiflora spp.) is

an economically important crop for many tropical and sub-tropical countries worldwide, and its production is affected by many diseases caused by viruses. However, there are no reports of mitoviruses associated with Passiflora spp. This study aimed to identify

mitoviruses associated with passionflower plants by molecular techniques. Double- strand RNA (dsRNA) extracted from accessions of Passiflora spp. plants with virus-like

symptoms was sequenced using Illumina HiSeq 2500 high-throughput sequencing system. Raw reads were de novo assembled, and 162 contigs with high similarity with plant mitoviruses were identified. Six sequences showing ORFs with mitovirus RdRp motifs and phylogenetically related to viruses of the genus Mitovirus were identified and named Passiflora mitovirus-like (PMV). Oligonucleotides were synthesized for PCR and RT-PCR and used to amplify the mitovirus-derived fragments of PMV1, 2, and 3 from RNA and DNA extracted from passionflower leaves. PMV1 and PMV2 could be amplified fromRNA and DNA from a high diversity of Passiflora spp, evidencing a possible endogenization or horizontal gene transfer (HGT). The complete genome of the PMV1 and PMV2 NERVES was recovered from passionfruit samples, cloned, and sequenced, and they have small ORFs showing identities with mitovirus. However, no DNA corresponding to PMV3 was detected, excluding the endogenization of this sequence. Overall, we present here the first evidence of mitovirus infection in Passiflora spp. The recovery of mitovirus-derived fragments from RNA samples indicates that PMV1 and 2 are capable of being transcribed.