Phylogenetic relationships in the family Alloherpesviridae

Abstract

Phylogenetic relationships among herpesviruses (HVs) of mammals, birds, and reptiles have been studied extensively, whereas those among other HVs are relatively unexplored. We have reconstructed the phylogenetic relationships among 13 fish and amphibian HVs using maximum likelihood and Bayesian analyses of amino acid sequences predicted from parts of the DNA polymerase and terminase genes. The relationships among 6 of these viruses were confirmed using the partial DNA polymerase data plus the complete sequences of the terminase, helicase, and triplex protein genes; the position of these viruses among all other sequenced HVs was also investigated using the complete terminase gene. The results established the monophyly of the fish and amphibian HVs (Alloherpesviridae) separate from the HVs of mammals, birds, and reptiles (Herpesviridae) and the single recognized HV of bivalve mollusks (Malacoherpesviridae) in the order Herpesvirales. Two major clades in the family Alloherpesviridae were recognized: one consisting of viruses from cyprinid and anguillid hosts and the other of viruses from ictalurid, salmonid, acipenserid, and ranid hosts. A comparison of virus and host phylogenies suggested that closely related HVs in this family may have coevolved with their hosts, whereas significant codiversification was not apparent for the more distantly related viruses.KEY WORDS: Alloherpesviridae · Fish herpesviruses · Frog herpesviruses · Phylogeny · Coevolution· DNA polymerase · Terminase Resale or republication not permitted without written consent of the publisherDis Aquat Org 84: [179][180][181][182][183][184][185][186][187][188][189][190][191][192][193][194] 2009 pesviridae, divided into the subfamilies Alphaherpesvirinae, Betaherpesvirinae, and Gammaherpesvirinae) containing mammalian, avian, and reptilian viruses, one (Alloherpesviridae) containing fish and amphibian viruses, and one (Malacoherpesviridae) containing a single virus, OsHV1. The taxonomic structure of the family Herpesviridae has been well established phylogenetically, and the viruses are characterized by approximately 43 homologous genes that were presumably inherited from a common ancestor (McGeoch et al. 2006). The erection of the 2 new families was driven by the findings that these viruses are but tenuously related to the fish and amphibian HVs, which share at least 13 homologous genes with each other (Aoki et al. 2007), and that OsHV1 is related only marginally to all other HVs (Davison et al. 2005b). Indeed, the best, and perhaps only, sequence-based evidence supporting a common ancestry for all HVs resides in a single gene, that encoding the putative ATPase subunit of terminase (hereafter terminase; an enzyme complex involved in packaging DNA into capsids), in which 5 regions are conserved (Davison 1992(Davison , 2002. This protein is also conserved to a lesser extent in T4-like bacteriophages in the family Myoviridae (Davison 1992). Indeed, the perceived utilization of a similar enzyme complex for packaging DNA into preformed capsids...

Koi Herpes Virus: A Review and Risk Assessment of Indian Aquaculture

“…The first clade comprises anguillid and cyprinid herpesviruses, which possess large genomes (245-295 kb). The second clade comprises ictalurid, salmonid, acipenserid, and ranid herpesviruses, which have smaller DNA genomes (134-235 kb) [86]. Interestingly, KHV resembles the poxviruses by the presence of thymidylate monophosphate, ribonucleotide reductase and a B22R-like genes [38].…”

Ostreid herpesvirus: A pathogen of oysters

“…Based on terminase gene's taxonomy-tree, the virus of oyster is a clade a part from the other Herpesvirus. In Figure 2 herpesviruses dataset and phylogenic tree from Waltzek, et al are shown [11]. Malacoherpesviridae contains Ostreid Herpesvirus-1 (OsHV-1) as its sole member, in the genus Ostreavirus [12].…”

Is There Any Species Specificity in Infections with Aquatic Animal Herpesviruses?–The Koi Herpesvirus (KHV): An Alloherpesvirus Model

“…The most previously researched Alloherpesvirus, channel catfish herpesvirus (Ictalurid herpesvirus 1 (IcHV-1), CCV) infects channel catfish but also blue catfish [8] and possibly other catfish species or subspecies while IcHV-2 was detected in black bullhead (Ameiurus melas) and in channel catfish (Ictalurus punctatus) [9]. Members of the salmonivirus group are known to often infect more than one species: salmonid herpesvirus 1 (SaHV-1) have been detected in rainbow trout (Ocorhynchus mykiss) [3] but also in Chum salmon (O. keta) and Chinook salmon (O. kisutch) [10]. SaHV-2 was considered to infect all salmonid species [3] and SaHV-3 was detected in different fish and hybrids of the genus Salvelinus [3,11,12].…”

“…Members of the salmonivirus group are known to often infect more than one species: salmonid herpesvirus 1 (SaHV-1) have been detected in rainbow trout (Ocorhynchus mykiss) [3] but also in Chum salmon (O. keta) and Chinook salmon (O. kisutch) [10]. SaHV-2 was considered to infect all salmonid species [3] and SaHV-3 was detected in different fish and hybrids of the genus Salvelinus [3,11,12]. In addition to cyprinid herpesviruses 1,2 and 3 the eel herpesvirus (HVA, AngHV-1) is also included in the genus Cyprinivirus.…”

“…Virulence associated with herpesviral infection is often initially displayed in immunologically weakened hosts or during primary infection of a naïve host. The characteristics of KHV, including the morphology investigated by electron microscopy [1,2], and phylogeny meets the taxonomical criteria for viruses of the family Alloherpesviridae [3], which have been shown to be non-host-specific, but sometimes causing disease in one species. Within this family are four genera grouped as the Batrachovirus, Salmonivirus, Ictalurivirus and Cyprinivirus.…”