Aquaculture America 2020

February 9 - 12, 2020

Honolulu, Hawaii

IDENTIFICATION OF NORTHERN SNAKEHEAD FISH-DERIVED ANTIMICROBIAL PEPTIDE GENES

Fang Zeng*, Chaonan Zhang, Jinzeng Yang, Jixing Zou
College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, Honolulu, HI, USA
 

The Northern snakehead (Channa argus ) is an important and staple farming fish species in China. In recent years, germplasm degeneration and intensive culture pattern have caused serious disease problems to the Northern snakehead culture industry, which hinders the green and sustainable development of the Northern snakehead farming industry. An effective way to solve the above problems is to improve the disease-resistant traits of Northern snakehead by molecular marker-assisted selection or transgenesis-based breeding techniques. To provide important candidate genes for genetic improvement of disease-resistant traits of Northern snakehead, this project aimed to screen antimicrobial peptide (AMP) genes from Northern snakehead genome, determine their functions and elucidate their action mechanisms. Three AMP-like genes have been selected by blasting the  conserved amino acid  (aa) sequences of teleost fish-derived five classic families of AMP against the sequence data base of Northern snakehead genome . A Channa argus-derived hepcidin-like gene  (caHep ) was cloned. The caHep  gene contains an open reading frame of 270 bp (encoding 89 amino acids).  The 89 aa mature peptide consists of 24 aa, 40 aa and 25 aa for signal peptide, prodomain and mature peptide, respectively. CaHep expression plasmid pCMS-EGFP-caHep and the control plasmid pCMS -EGFP were constructed. Transfection of pCMS-EGFP-caHep  plasmid into cultured human embryonic kidney cells (HEK293) resulted in expression of EGFP and caHep . The culture supernatant of caHep -expressing HEK293 cells showed significantly increased resistance activities against  Aeromonas veronii compared with the control. Furthermore , chemically s ynthesized caHep mature peptide showed  significantly increased resistance activities against  Aeromonas veronii compared with the control. Scanning electron microscope analysis indicated that t reatment with caHep peptide induced significant  cell  membrane damage  on  Aeromonas veronii in comparison to the control.