Cloning and nucleotide sequence analyses of 11 genome segments of two American and one British equine rotavirus strains

Abstract

Group A equine rotavirus (ERV) is the main cause of diarrhea in foals and causes severe economic loss due to morbidity and mortality on stud farming worldwide. Molecular evolution of equine rotaviruses remains understudies. In this study, whole-genomic analysis of 2 group A ERV, FI-14 (G3P[12]), H-2 (G3P[12]) isolated from American, and FI23 (G14P[12]) from British was carried out and genotype constellations were determined as G3-P[12]-I6-R2-C2-M3-A10-N2-T3-E2-H7 for FI-14; G14-P[12]-I2-R2-C2-M3-A10-N2-T3-E2-H7 for FI23; and G3-P[12]-I6-R2-C2-M3-A10-N2-T3-E2-H7 for H-2, respectively. With the exception of the VP7 and VP6 gene, 2 G3P[12] strains (FI-14 and H-2) and one G14P[12] strain (FI23) were highly related genetically. Of note, the VP6 genotype of H-2 strain was previously reported to be I2, however, sequence and phylogenetic analyses demonstrated that it was I6. Therefore, it showed that G3P[12] ERV strains and G14P[12] ERV strains bore a distinct VP6 genotype: I6 for G3P[12] strains and I2 for G14P[12] strains. Moreover, it demonstrated that T-cell epitope 299P-300P/Q residues (PP/Q) of VP6 may be considered as I2 ERV typical molecular marker, which facilitates the analysis of the molecular evolution of equine rotaviruses.

Equine rotavirus infection

“…Interestingly, the G3 and G14 genotypes of VP7 are strongly associated with the I6 and I2 genotypes of VP6, respectively [44]. The E12 genotype of NSP4 has been detected only in Argentinian equine RVAs, whereas the E2 genotype has been detected in other countries [24,38,40,51,54].…”

Genetic linkage of capsid protein-encoding RNA segments in group A equine rotaviruses

“…Genomes of equine RVA G3P [12] and G14P[12] are highly conserved, and only three gene segments have shown different genotypes (i.e. VP7: G3 and G14; VP6: I2 and I6; and NSP4: E2 and E12) in all complete genomes available currently (Ma et al, 2015;Matthijnssens et al, 2012;Nemoto et al, 2015).…”