Analysis of Unique Genes Reveals Potential Role of Essential Amino Acid Synthesis Pathway in Flavobacterium covae Virulence
Year: 2025
Type: report
Abstract: Flavobacterium covae is one of the four Flavobacterium species causing columnaris disease among warm-water fish.Flavobacterium covae strain 94-081 is highly virulent in channel catfish (Ictalurus punctatus) compared to F. columnare strain ATCC 49512.This study focused on analyzing the unique genes present in the genome of F. covae strain 94-081 compared to the genome of F. columnare strain ATCC 49512.Our comparative genome analysis revealed presence of 36 proteins unique to F. covae.Within the unique genes, nine genes (leuA, leuB, leuC, leuD, ilvA, ilvB, ilvC, ilvD, and ilvH) were associated with the branched-chain amino acids (BCAA) biosynthesis pathway and seven genes (cysD, cysE, cysG, cysH, cysI, cysK, and cysN) were involved in the cysteine biosynthesis pathway.Among the BCAA biosynthesis-related genes, ilvC (ketol-acid reductoisomerase) and ilvD (dihydroxy-acid dehydratase) showed potential interaction with catfish proteins based on the host-pathogen interaction database analysis.To investigate the functional significance of the BCAA pathway, we generated F. covae leuD (FcΔleuD) and ilvD (FcΔilvD) mutants.The deletion of leuD and ilvD genes did not cause growth defects, but they showed reduced virulence in catfish (47.5% and 70% mortality, respectively) compared to the wild-type strain (FcWT) (100% mortality).This is the first report indicating a potential role of the BCAA pathways in F. covae virulence.Further studies will reveal the role of the cysteine biosynthesis pathway and other unique genes on F. covae virulence.
Language: English
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
OpenAlex ID: W4407898285