Virome Analysis of Normal and Growth Retardation Disease-Affected Macrobrachium rosenbergii.

The giant freshwater prawn, Macrobrachium rosenbergii, is an important aquaculture species in China. Growth retardation disease (GRD) is a common contagious disease in , resulting in slow growth and precocious puberty in prawns, and has caused growing economic losses in the industry. To investigate the viral diversity of and identify potentially high-risk viruses linked to GRD, virome analysis of the GRD-affected and normal was carried out using next-generation sequencing (NGS). A total of 327 contigs (>500 bp) were related to viral sequences belonging to 23 families/orders and a group of unclassified viruses. The majority of the viral contigs in belonged to the order , with the family being the most abundant in both the diseased and normal groups. Furthermore, 16 RNA viral sequences with nearly complete genomes were characterized and phylogenetically analyzed, belonging to the families , , , , and as well as three new clades of the order . Notably, the cross-species transmission of a picorna-like virus was observed between and plants. The "core virome" seemed to be present in the diseased and normal prawns. Still, a clear difference in viral abundance was observed between the two groups. These results showed that the broad diversity of viruses is present in and that the association between viruses and disease of needs to be further investigated. Growth retardation disease (GRD) has seriously affected the development and economic growth of the aquaculture industry. Our virome analysis showed that diverse viral sequences were present in , significantly expanding our knowledge of viral diversity in . Some differences in viral composition were noted between the diseased and normal prawns, indicating that some viruses become more abundant in occurrences or outbreaks of diseases. In the future, more research will be needed to determine which viruses pose a risk for . Our study provides important baseline information contributing to disease surveillance and risk assessment in aquaculture.