Characterization of a not so new potexvirus from babaco (Vasconcellea x heilbornii)

Abstract

A new member of the genus Potexvirus was fully sequenced and characterized. The virus was isolated from babaco (Vasconcellea x heilbornii), a natural hybrid native to Ecuador. The virus contains a 6,692 nt long genome organized in five open reading frames in an arrangement typical of other potexviruses. Sequence comparisons revealed close relatedness with Papaya mosaic virus (PapMV), Alternathera mosaic virus (AltMV) and Senna mosaic virus (SenMV), exhibiting nucleotide identities up to 67% for the polymerase (Pol) and 68% for the coat protein (CP), with deduced amino acid identities of 70% and 72% for the Pol and CP, respectively. The presence of an AlkB domain, in the polymerase region, was observed. Terminal nucleotide sequences were conserved across potexviruses with characteristic motifs and predicted secondary structures at the 3’ UTR. Although serologically undistinguishable from PapMV and AltMV, the new virus showed differences in host range and symptom induction. The name babaco mosaic virus is proposed for this newly characterized Potexvirus. The complete genome sequence of the new virus has been deposited in NCBI GenBank under accession number MF978248.

Phylodynamics and Coat Protein Analysis of Babaco Mosaic Virus in Ecuador

“…BabMV is a potexvirus that is widely distributed in the main babaco-producing provinces of Ecuador; it has been previously reported to infect other caricaceaes such as papaya and chamburo [9]. In this work, a total of 36 BabMV isolates were obtained from babaco (n = 33) and chamburo (n = 3) plants.…”

“…The present work supports findings by Gómez et al (2012) [22] on a distinct potexvirus, pepino mosaic virus, where a high evolutionary rate was also reported. Particularly, the high evolutionary rate of BabMV could have contributed to its hability to emerge in new hosts such as chamburo and to induce symptoms in mechanically inoculated papaya plants [9].…”

“…Taken together, babaco has great potential to become a major product in the fruit market. However, the crop is seriously affected by pests and diseases caused by fungi, bacteria, nematodes, and several viruses including babaco mosaic virus (BabMV) [9,10].…”

“…Based on demarcation criteria and its complete genome sequence, BabMV was proposed as a new member of the genus Potexvirus [9]. This pathogen may have been previously reported from Italy in 1989 as babaco yellow mosaic virus [9,11], which was later observed using electron microscopy [12]. No further studies have been made on the structural characteristics of the virus.…”

“…No further studies have been made on the structural characteristics of the virus. Aminoacid sequence identity between BabMV and its closest relatives, papaya mosaic virus (PapMV) and alternanthera mosaic virus (AltMV), is 70% for the polymerase and 72% for the coat protein (CP) [9]; however, these viruses were serologically indistinguishable [9,11]. There are no structures available for the CP of viruses related, but bioinformatic modeling can help to understand how these divergent sequences, belonging to different potexvirus species, can conserve a structure that is indistinguishable by antibodies.…”