[Molecular characterization of a rare rotavirus (:) strain genotype G2P[9] isolated from a child with acute gastroenteritis].

Abstract

Rotaviruses exhibit a high degree of variability, which is ensured by the process of reassortment and antigenic drift. This leads to significant genetic diversity, including the emergence of strains with rare and unusual genotypes. This study, for the first time, provides a molecular genetic characterization of a rare RVA strain with the genotype G2P[9] based on all genome segments. To conduct a molecular genetic characterization of a rare strain of RVA genotype G2P[9] based on all genome segments, as well as to compare the strain with previously characterized representatives of subgroup BA222 from Nizhny Novgorod. Rotavirus-positive stool samples from children were analyzed using PCR-genotyping and PAGE. For the isolate under study, cDNA fragments of each of the 11 genes (,,,) were sequenced. Nucleotide and amino acid sequence analysis and phylogenetic tree construction were performed using MEGA X. In the period 2022-2023, a single strain of the unique genotype G2P[9] was identified in Nizhny Novgorod, characterized by a "broad" RNA electrophoretype (G2-P[9]-I2-R2-C2-M2-A3-N2-T3-E3-H3). The study showed that the origin of this strain is associated with reassortment processes between Nizhny Novgorod Wa- and BA222-like RVA, as well as isolates of the G3P[9] genotype from China. The studied strain, along with rotaviruses from China, differed from the Nizhny Novgorod BA222-like strains by the presence of 43 nucleotide substitutions in nine genes. These differences resulted in ten amino acid substitutions, eight of which were radical. All radical substitutions were located in the functionally active regions of the VP1, VP3, and VP4 proteins, which play a key role in the replicative cycle of rotaviruses. We characterized a strain with the rare G2P[9] genotype based on its complete genotype for the first time in Russia and globally. These results expand our understanding of the diversity of reassortant rotaviruses and complement our knowledge of the genotypic structure of the rotavirus population in Nizhny Novgorod. The wide genetic diversity of rotaviruses, maintained by reassortment and antigenic drift, may facilitate rotaviruses' ability to overcome immunological pressure. Therefore, continuous molecular monitoring of circulating rotavirus variants is necessary to monitor the emergence of new variants and assess changes in rotavirus virulence following reassortment processes.