Sequence and phylogenetic analysis of H10 subtypes
Two H10N4 strains (JDS120613-H10N4 and JDS120662-H10N4) were isolated
from Common teal(Anas crecca )and Mallard (Anas
platyrhynchos ) at Jiuduansha Natural Reservation Zone in 2018. Except
for one polymerase acidic (PA) gene, the whole genome sequences of the
two strains were obtained, and the sequence homology analysis showed
that they shared 92.9% to 99.3% nucleotide sequence identity among the
seven gene segments. A BLAST search
(https://blast.ncbi.nlm.nih.gov/Blast.cgi )
revealed that the two hemagglutinin (HA) genes of these H10N4 strains
were most closely related to that of A/duck/Mongolia/709/2015(H10N7),
while their neuraminidase (NA) genes were highly related to those genes
in A/duck/Mongolia/258/2011(H8N4) and
A/garganey/Bangladesh/38920/2019(H7N4). The matrix (M) gene of
JDS120662-H10N4 had the most similarity with H6N2 virus isolated in
Hubei, and the other internal genes of the two H10N4 strains
shared most
(>98.36%) similarities with H10, H7, H11, H8, H12 and H3
subtypes isolated in Hokkaido, Mongolia, Egypt, Bangladesh, Georgia and
Tottori (Table 2).
In the phylogenetic trees, the HA and NA genes of JDS120613-H10N4 and
JDS120662-H10N4 strains were grouped together and clustered in the
Eurasian Lineage. The HA genes showed a close relationship with the
H10N7 strains circulating in ducks in Cambodia and Mongolia, and NA
genes were associated with H7N4 and H8N4 viruses isolated in garganey
and ducks in Bangladesh (Figure 1). PB1 polymerase (PB1) and M genes of
the two H10N4 strains were all grouped together in a small sublineage,
and were closely related to H3N2, H5N2 and H6N2 viruses circulating in
Japan and China. Nucleoprotein(NP)gene of JDS120662-H10N4 was closed
to H7N7 and H7N1 viruses isolated from Tottori and South Korea, and the
NP gene of JDS120613-H10N4 was clustered with them in a small group. PB2
polymerase (PB2) and nonstructural (NS) genes of the two strains were
all clustered in two different groups and were genetically close to
those of viruses isolated from ducks circulating in Tomsk, Mongolia,
Japan, Bangladesh and China located along the
Eurasian-Australian
Migration Flyway (Figure S1).