Transcriptome In Combination With Experimental Validation Unveils Hub Immune-Related Genes In Oriental River Prawn Macrobrachium Nipponense Against Spiroplasma Eriocheiris Challenge

Spiroplasma eriocheiris (S. eriocheiris) infection has caused heavy economic losses in Macrobrachium nipponense (M. nipponense) aquaculture industry. However, the interplay between immune responses of M. nipponense and S. eriocheiris infection has not yet been fully elucidated. Herein, full-length transcriptome profiling of M. nipponense hemocytes was performed with or without S. eriocheiris challenge. In total, 20,441 high quality unigenes were obtained, among which 733 differentially expressed genes (DEGs) were found, including 309 up-regulated and 424 down-regulated genes. Protein-protein interaction network (PPI) analysis of DEGs identified 4 hub immune-related genes, including MAP kinase-interacting serine/threonine-protein kinase 1 (MNK1), C-type lectin 4 (CTL4), gamma-interferon-inducible lysosomal thiol reductase (GILT), and anti-lipopolysaccharide factor (ALF). Tissue distribution and expression analysis of the key immune-associated genes demonstrated that they were widely expressed in 6 tissues, especially in gills, and were up-regulated by S. eriocheiris challenge. M. nipponense challenged by S. eriocheiris exhibited a significant reduction of bacterial clearance ability when the hub genes were silenced via RNA interference. Overall, our results indicated that the 4 hub immune-related genes play a vital role in anti-S. eriocheiris infection, thus providing insights into the immune defensive response mechanisms of M. nipponense against S. eriocheiris infection.