Lcalmnb2: Asian seabass gene involved in resisting SGIV

Diseases cause significant economic loss in aquaculture. Molecular breeding is an effective way to improve long-lasting disease resistance. DNA markers associated with disease resistance are essential in molecular breeding. The Singapore grouper iridovirus (SGIV) causes severe mortality in hatcheries of Asian seabass (Lates calcarifer). To identify DNA markers associated with SGIV resistance and understand more about functions of candidate genes in SGIV resistance, the lmnb2 gene from L. calcarifer was characterized. The gene contained 13 exons and 12 introns. Its open reading frame (ORF) of 1731 bp encoded a protein with 576 amino acids. A SNP, identified in the first intron of the gene, was significantly associated with SGIV resistance. Lcalmnb2 was ubiquitously expressed in organs of the healthy Asian seabass. In vitro studies revealed that Lcalmnb2 promoted cell proliferation and migration. Overexpression of the gene repressed the replication of SGIV in Asian seabass cells, while knockdown of the gene prompted SGIV replication. In virus-infected cells, SGIV utilized Lamin B2 for host DNA transport during viral replication, leading to the induction of nuclear abnormalities. This study sheds new light on the involvement of Lcalmnb2 in resisting SGIV infection. The identified SNP may serve as a useful DNA marker for selecting SGIV-resistant Asian seabass individuals in future breeding programs.