Abstract: Oysters, the main vector of NoVs, contain almost all GI and most GII genogroup. In order to explore the diversity of the NoVs in oysters, this study aimed to evaluate four virus enrichment methods which were usually used in metagenomics study (PEG6000 precipitation method, ultracentrifugation method, filtration method and direct extraction method). Here, reverse transcription quantitative PCR (RT-qPCR) was adopted to calculate the Lentivirus (with GII.4 NoVs gene) copies before and after treated with the four methods, and recovery rate of Lentivirus was the evaluation indicator. Besides that, 16S rRNA PCR was conducted to compare the microorganism contamination. Both results showed that these four methods had no obvious difference, and the direct extraction method had relatively higher recycle rate and more serious microorganism pollution. It demonstrated direct extraction method has relatively good superiority, which is more suitable to extract RNA for NoVs diversity in oysters.

Key words: norovirus, oyster, direct extraction, diversity research