IDENTIFICATION AND FUNCTIONAL ANALYSIS OF CANDIDATE GENES FOR RESISTANCE TO VIRAL NERVOUS NECROSIS DISEASE IN ASIAN SEABASS

Abstract

Asian seabass is an important food fish in Southeast Asia and Australia. Viral nervous necrosis (VNN) is one of its major diseases, leading to a huge economic loss. This thesis aims to identify causative genes involved in host defense against nervous necrosis virus (NNV) and to identify SNPs in genes associated with NNV resistance to accelerate genetic improvement for NNV resistance in Asian seabass. The study verified that the gab3 gene is an NNV resistance gene and the identified SNPs (allele G and C) associated with NNV resistance can be applied for selection of Asian seabass resistance to NNV at the juvenile stage. Due to the brain is the main attack target of NNV in Asian seabass, brain RNA-seq was conducted to obtain DEGs for NNV resistance. These results suggested that the rrm1 gene is a NNV resistance gene. The identified SNP (allele A) in rrm1 associated with NNV resistance can be used in the marker-assisted-selection (MAS) for NNV resistance at the fingerling stage of Asian seabass to accelerate genetic improvement. In summary, my study demonstrated that the combination of QTL mapping, GWAS, RNA-seq, association study and functional analysis is an effective strategy in identifying causative genes for NNV resistance.