3.5 Amino acid polymorphism analysis
To further explore the characteristics of both newly identified NDRV
strains, amino acid polymorphism of the σC proteins was compared with
reference strains. The results showed that most of the amino acid
mutations in both newly identified NDRV isolates located in the σC
protein head domain (Table 1), such as P233S, V253A, and A298V,
indicating both isolates were closely related to each other. Meanwhile,
some mutations were only found in HNXX-1/2021 & HNJZ-2/2021 (P233S in
σC protein head domain), HeNXX-1/2021 (E305G, A328R, and T329Q in σC
protein head domain) and HNJZ-2/2021 (A328R and T329Q in the σC protein
head domain). Moreover, there was a unique amino acid mutation site
(Q158H) in the σC protein shaft domain of both newly identified NDRV
strains.