Page 139 - 《渔业研究》2025年第5期

680 渔 业 研 究 第 47 卷

Identification of WNK genes in channel catfish (Ictalurus punctatus) and
its response to ESC

ZHANG Lu，SHE Qiyuan，LI Chao *
(School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China)

Abstract: [Background] With no lysine kinases (WNK) are regulators of transporters, channels, and paracellu-
lar proteins. They play crucial roles in ion transport processes, maintaining cellular osmotic pressure, and regula-
ting cell volume homeostasis. Currently, no studies have conducted systematic identification of the WNK gene
family in channel catfish (Ictalurus punctatus) and investigate its role in immune responses. [Objective] This
study aims to systematically identify the WNK gene family in I. punctatus and investigate their roles during Ed-
wardsiella ictalurid infection. [Methods] Through bioinformatic approaches, the WNK gene family sequences
of the other species were used to blast against the genome of I. punctatus to identify the WNK gene family se-
quences in I. punctatus. The WNK gene family in I. punctatus was annotated and confirmed through domain
analysis and phylogenetic analysis. Quantitative real-time polymerase chain reaction (qPCR) was employed to
analyze the differential expression patterns of WNK genes between E. ictaluri-susceptible (YG groups) and
-resistant (KX groups) I. punctatus populations following E. piscicida infection. [Results] Six WNK genes
were identified in I. punctatus, namely WNK1a, WNK1b, WNK2, WNK3, WNK4a, and WNK4b. After E. ictaluri
infection, except for WNK1b in the intestine of the YG48 group [Enteric septicaemia of catfish (ESC)-suscept-
ible I. punctatus that died within 24−48 hours], WNK1a/b in the liver and intestine of the other YG groups and
KX groups all showed a down-regulated trend; WNK2, WNK3, and WNK4a/b in the liver and intestine of both
YG and KX groups mostly presented a significant up-regulated trend, with the expression levels in the YG
groups being significantly higher than those in the KX groups. [Conclusion] WNK genes in the intestinal and
liver of I. punctatus are involved in the pathogenesis of ESC. The results of the study provide a reference for
analyzing the molecular genetic mechanism of disease-resistant traits.
Key words: Ictalurus punctatus; Edwardsiella ictaluri; with no lysine kinases (WNK); disease resistance traits