Analysis of the genetic diversity of the lymphocystis virus and its evolutionary relationship with its hosts

Abstract

Lymphocystis disease virus (LCDV) is the causative agent of lymphocystis disease. In this study, the mcp gene of LCDV and the cyt b gene of the host fish were selected as molecular markers, and the phylogenetic relationships between LCDV and its host were analyzed. The 25 LCDV isolates examined in this study were attributed to seven LCDV genotypes: genotype I (LCDV-1), genotype II (LCDV-cn, etc.), genotype III (LCDV-rf), genotype IV (LCDV-rc and LCDV-sb), genotype V (LCDV-cb), genotype VI (LCDV-tl), and genotype VII (LCDV-sa). Genotype VII is a new genotype. LCDV1 was found to have differentiated first, followed by LCDV-rf; then LCDV-tl; LCDV-cb; and then LCDV-sa; and by LCDV-rc and LCDV-sb; and finally by LCDV-cn, LCDV-C, and LCDV-jf. From the host evolutionary perspective, Rachycentron canadum was found to have differentiated first, followed by Trichogaster leeri, Chanda baculis, and Sebastes schlegeli, Lateolabrax sp., Sparus aurata, Platichthys flesus, and Paralichthys olivaceus. Comparison of the phylogenies of the host fish species and LCDVs revealed no significant evidence of cospeciation between LCDVs and their host fish. In-depth studies of the genetic variation in LCDVs can enhance our understanding of the mechanism of LCDV infection, which may provide important insights into the prevention and treatment of lymphocystis disease.

Voltage-Dependent Anion Channel Protein 2 (VDAC2) and Receptor of Activated Protein C Kinase 1 (RACK1) Act as Functional Receptors for Lymphocystis Disease Virus Infection

“…LCDV has infected more than 140 wild and cultured species of marine, brackish water, and freshwater fish worldwide, causing huge economic losses to the aquaculture industry (3,4). In China, LCD is often observed in some cultured fish, especially the flounder Paralichthys olivaceus; even though the disease rarely causes death, it may lead to secondary infection by other microorganisms, resulting in high mortality rates (5)(6)(7). LCDV is a macromolecular DNA virus with an envelope (8,9), and the complete genome sequences of two LCDV isolates, LCDV-1 from the flounder Platichthys flesus in Europe and LCDV-C from the flounder P. olivaceus in China, have been determined (10,11).…”

Identification and characterization of a novel lymphocystis disease virus isolate from cultured grouper in China

“…We proposed that different LCDV isolates and their hosts might evolve independently, although genetic variation usually occurs in many DNA viruses during their co‐evolution with hosts (Yan et al . ).…”

Lymphocystis disease virus: its importance in aquaculture

“…The genetic diversity of LCDV has been related to the host fish species (Kitamura et al 2006a,b;Hossain et al 2008). However, when studying the evolutionary relationship of LCDV and its hosts, Yan et al (2011) did not obtain significant evidence of cospeciation between LCDV genotypes and their host fish species.…”