The genome sequence of Pavonine herpesvirus 1, a novel Mardivirus infecting peafowl

Abstract

Avian alphaherpesviruses of the genusMardivirusinclude several economically important pathogens, such as the tumour-causing Marek’s disease virus (MDV-1) of chickens. However, the diversity of related viruses in wild and non-model avian hosts remains poorly characterised. Here, we describe the genome of Pavonine herpesvirus 1 (PaHv1), a novelMardivirusinfecting peafowl (Pavospp.). Through de novo assembly of reads generated from whole-genome sequencing of 370 captive peafowl, we generated a single viral genomic scaffold of 134,149 bp in length and an estimated total genome size of ∼146 kbp following reconstruction of terminal repeat regions. PaHv1 exhibits canonicalMardivirusUL-IRL-IRS-US genomic architecture and encodes 169 open reading frames, of which 82 have clear orthologs in otherMardivirusspecies. Comparative genomic analyses revealed strong syntenic concordance between PaHv1, MDV-1, MDV-2 and Meleagrid alphaherpesvirus 1 (HVT), but with notable absences of the Meq oncogene, viral interleukin-8 (vIL8), and a truncated pp38 gene – genes known to underpin oncogenicity and virulence in MDV-1. Phylogenetic analysis places PaHv1 firmly within theMardivirusgenus as a sister to the poultry-associated MDV-1 and MDV-2 viruses, but distinct from a previously described Phasianid herpesvirus with a partial DNA terminase sequence. PaHv1 was detected predominantly in feather-derived samples, consistent with replication or persistence in the feather follicle epithelium. Taken together, these findings identify PaHv1 as a novel, likely non-oncogenicMardivirus, expanding our understanding of herpesvirus diversity, evolution and host association in galliform birds.

Importance

Herpesviruses cause several economically important diseases in domesticated birds, including Marek’s disease, duck plague and infectious laryngotracheitis. Despite this, our understanding of herpesviruses infecting wild and semi-wild birds remains limited. Here, we present the genome of Pavonine herpesvirus 1 (PaHv1), a virus in theMardivirusgenus which infects peafowl. Based on comparative genomics with otherMardivirusspecies, we note the absence of several genes important for the high virulence of Marek’s Disease Virus, such as the Meq oncogene, viral interleukin-8 and a truncated pp38. This, taken together with absence of clinical disease in preliminary observations, suggests that PaHv1 causes either a subclinical infection or one with mild symptoms. Our work expands the known evolutionary breadth of avian herpesviruses in theMardivirusgenus. In addition, PaHv1 may provide a useful starting point for the development of novel vaccine vectors for pathogenic herpesvirus infections.