College of Life Science and Technology, Southwest University for Nationalities, Chengdu, PR China.
Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Chengdu, PR China.
J Gen Virol. 2020 Jul;101(7):701-711. doi: 10.1099/jgv.0.001426.
Yak is an iconic species of the Qinghai-Tibet Plateau, which is the world's highest plateau. Here, a total of 541 yak diarrhoeic samples were collected from 69 farms in four provinces in the Qinghai-Tibet Plateau from April 2015 to June 2018, and 73.6 % of samples were detected as Bovine Rotavirus A (BRVA) positive by RT-PCR assay. Two G genotypes (G6, G10) and two P genotypes (P[1], P[11]) were determined, in which G6P[1] BRVA was the predominant strain. Moreover, VP7 and VP4 of these G6P[1] strains showed unique amino acid mutations, such that they clustered into an independent branch in the phylogenetic tree. A strain of BRVA designated as RVA/Yak-tc/CHN/QH-1/2015/G6P[1] was isolated successfully using MA104 cells, and the virus titre was determined as 10 TCID ml. The genome of strain QH-1 had a G6-P[1]-I2-R2-C2-M2-A3-N3-T6-E2-H3 genotype constellation. QH-1 was identified as a reassortment strain of BRVA, human RVA and ovine RVA based on the nucleotide identity and phylogenetic tree of 11 gene segments, indicating its public health significance. To the best of our knowledge, this is the first report on the molecular prevalence and genome characteristics of BRVA in yak, contributing to further understanding of the epidemic and genetic evolution of BRVA.
牦牛是青藏高原的标志性物种，也是世界上海拔最高的高原。本研究于 2015 年 4 月至 2018 年 6 月期间，从青藏高原四个省的 69 个农场共采集了 541 份牦牛腹泻样本，通过 RT-PCR 检测，73.6%的样本检测为牛轮状病毒 A（BRVA）阳性。共鉴定出 2 个 G 基因型（G6、G10）和 2 个 P 基因型（P[1]、P[11]），其中 G6P[1]BRVA 是主要流行株。此外，这些 G6P[1]株的 VP7 和 VP4 具有独特的氨基酸突变，使其在系统进化树上聚类为一个独立的分支。使用 MA104 细胞成功分离到一株命名为 RVA/Yak-tc/CHN/QH-1/2015/G6P[1]的 BRVA 毒株，病毒滴度为 10 TCID ml。株 QH-1 的基因组具有 G6-P[1]-I2-R2-C2-M2-A3-N3-T6-E2-H3 基因型组成。基于 11 个基因片段的核苷酸同源性和系统进化树，QH-1 被鉴定为 BRVA、人轮状病毒和羊轮状病毒的重组株，表明其具有公共卫生意义。据我们所知，这是首次报道牦牛 BRVA 的分子流行情况和基因组特征，有助于进一步了解 BRVA 的流行和遗传进化。
