1 INTRODUCTION
Avian reovirus (ARV) has caused immense economic problems in the
chicken, duck, goose, and turkey industries worldwide
(Palya et al., 2003,
Rosa et al., 2014). Waterfowl reoviruses
(WRVs) have been associated with various disease conditions in ducks and
geese of different species, including Muscovy duck white spot disease
caused by classical Muscovy duck reovirus (MDRV)
(Yun et al., 2013,
Farkas et al., 2014,
Kuntz-Simon et al., 2002,
Le Gall-Recul et al., 1999,
Gaudry et al., 1972), duck hemorrhagic
necrotizing hepatitis, and spleen necrosis disease in ducks caused by
the novel Muscovy duck reovirus (N-MDRV)
(Yun et al., 2014,
Li et al., 2016,
Zhang et al., 2019) and the novel Duck
reovirus (NDRV) (Liu et al., 2011,
Chen et al., 2012b,
Yun et al., 2014,
Zhu et al., 2015,
Wang et al., 2020c,
Zhang et al., 2019,
Luo et al., 2021), spleen and liver
inflammation in geese caused by goose reovirus (GRV)
(Wang et al., 2013,
Palya et al., 2003,
Yun et al., 2013), hemorrhagic necrotic
hepatitis caused by the new type of goose reovirus (N-GRV) (Wang et al.
2002; Yun et al., 2012). It has been reported that WRVs can be
classified into two genotypes(Wang et al.,
2013). Genotype 1 comprises MDRV and GRV. While genotype 2 comprises
NDRV, N-MDRV, and N-GRV (Wang et al.,
2013).
The ARV genome includes ten segments that can be separated into three
classes based on their sizes: large (L1, L2, L3), middle (M1, M2, M3),
and small (S1, S2, S3, S4). The S1 segment is the only tricistronic gene
that encodes P10, P18, and σC proteins
(Zhu et al., 2015,
Benavente and Martínez-Costas, 2007). The
outer capsid proteins σC, σB, and μB of ARV are considerably variable,
whereas the inner capsid proteins are relatively conservative
(Benavente and Martínez-Costas, 2007).
Additionally, σC proteins play an essential role in viral fusion,
invasion, neutralizing antibody induction, and pathogenicity
(Du et al., 2020,
Ma et al., 2012,
Shih et al., 2004,
Benavente and Martínez-Costas, 2007).
Meanwhile, σC is regarded as the most variable protein of all the ARV
proteins (Benavente and Martínez-Costas,
2007). σC gene was usually used for epidemiological studies and viral
classification of ARVs (Luo et al., 2021,
Palomino-Tapia et al., 2018).
In recent years, many NDRV outbreaks emerged in China
(Wang et al., 2019,
Wang et al., 2020a,
Cao et al., 2019,
Zhang et al., 2019). However, few studies
have performed the evolutionary status analysis on NDRV in central
China. In this study, we isolated two NDRV strains from different duck
farms in Henan province, central China. To better understand the
molecular characteristics of the NDRVs circulating in duck populations,
the σC genes of both isolates were cloned, sequenced, and their
phylogeny and mutations were analyzed. This study systematically
describes the genetic and evolutionary characteristics of the ongoing
NDRV strains and highlights that continuous surveillance is needed to
develop proper vaccines and reasonable control programs.