Oyster production is an economic activity of great interest worldwide. Recently, oysters have been suffering significant mortalities from OsHV-1infection, which has resulted in substantial economic loses in several countries around the world. Understanding viral pathogenicity mechanisms is of central importance for the establishment of disease control measures. Thus, the present work aimed to identify and characterize miRNAs from OsHV-1 as well as to predict their target transcripts in the virus and the host. OsHV-1 genome was used for the in silico discovery of pre-miRNAs. Subsequently, viral and host target transcripts of the OsHV-1 miRNAs were predicted according to the base pairing interaction between mature miRNAs and mRNA 3′ untranslated regions (UTRs). Six unique pre-miRNAs were found in different regions of the viral genome, ranging in length from 85 to 172 nucleotides. A complex network of self-regulation of viral gene expression mediated by the miRNAs was identified. These sequences also seem to have a broad ability to regulate the expression of host immune-related genes, especially those associated with pathogen recognition. Our results suggest that OsHV-1 encodes miRNAs with important functions in the infection process, inducing self-regulation of viral transcripts, as well as affecting the regulation of Pacific oyster transcripts related to immunity. Understanding the molecular basis of host-pathogen interactions can help mitigate the recurrent events of oyster mass mortalities by OsHV-1 observed worldwide.

牡蛎生产是世界范围内备受关注的经济活动。最近，牡蛎因OsHV-1感染而遭受了致命的灭顶之灾，这已导致全球多个国家遭受重大经济损失。了解病毒的致病性机制对于建立疾病控制措施至关重要。因此，本工作旨在鉴定和鉴定OsHV-1中的miRNA，并预测其在病毒和宿主中的靶转录本。OsHV-1基因组用于计算机pre-miRNA的发现。随后，根据成熟miRNA与mRNA 3'非翻译区（UTR）之间的碱基配对相互作用，预测OsHV-1 miRNA的病毒和宿主靶转录本。在病毒基因组的不同区域中发现了六个独特的pre-miRNA，长度从85到172个核苷酸不等。鉴定了由miRNA介导的病毒基因表达自我调节的复杂网络。这些序列似乎也具有调节宿主免疫相关基因，特别是与病原体识别相关的基因表达的广泛能力。我们的结果表明，OsHV-1编码在感染过程中具有重要功能的miRNA，诱导病毒转录本的自我调节，并影响与免疫相关的太平洋牡蛎转录本的调节。