Page 210 - 《水产学报》2025年第8期

王玲，等 水产学报, 2025, 49(8): 089417

Research on the autophagy regulatory gene CgSVIP of Crassostrea gigas as
a biomarker of pathogen stress

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WANG Ling , GAO Lei , ZHOU Keli , GE Ping'an , FENG Xingyi ,
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WANG Lingling , SONG Linsheng
Liaoning Key Laboratory of Marine Animal Immunology and Disease Control,
Dalian Ocean University, Dalian 116023, China

Abstract: This study aimed to explore the expression characteristics of CgSVIP in response to pathogen-associated molecular
patterns (PAMPs) and pathogen stimulation in Crassostrea gigas, to discover the application of CgSVIP as a biomarker for dis-
ease early warning, and to analyze the mechanism of CgSVIP in regulating immune responses. This experiment utilized bioin-
formatics, quantitative real-time PCR (RT-qPCR), and Western blot to analyze the regulatory mechanism of CgSVIP as a
potential biomarker in disease early warning for C. gigas and its involvement in the autophagy regulation process induced by
pathogen stimulation. It was found that after stimulation with lipopolysaccharide (LPS), peptidoglycan (PGN), glucan (GLU)
and polyinosinic-polycytidylic acid [Poly(I:C)] for 12 h, the mRNA expression level of CgSVIP in haemocytes of C. gigas sig-
nificantly increased under all four PAMPs stimulations, and the average expression difference level was the most significant
among the differentially expressed genes in the transcriptome, with an average FPKM value of 106.938. Further, when C. gigas
was stimulated with LPS and Vibrio splendidus, the absolute expression value of CgSVIP in haemocytes significantly increased
at 12, 24 and 48 h after LPS stimulation, reaching 3.71, 3.52 and 3.55 lg copies/mL respectively; and significantly increased at
3, 6, 12, 48 and 72 h after V. splendidus stimulation, reaching 3.31, 3.12, 3.11, 3.42 and 3.26 lg copies/mL respectively. After
stimulation with V. splendidus for 12 h from March to October 2023, the expression level of CgSVIP in haemocytes signific-
antly increased except in March, reaching 3.52, 3.57, 3.45, 4.42, 3.77, 3.75 and 4.06 lg copies/mL respectively, with the highest
expression in July samples. Therefore, the absolute expression value of CgSVIP was within the range of 2.93-3.35 lg copies/mL
without PAMPs and pathogen stimulation, and within the range of 3.18-3.79 lg copies/mL with stimulation. It was preliminar-
ily determined that the threshold for CgSVIP to respond to PAMPs and pathogen stress was 3.35 lg copies/mL. To analyze the
mechanism of CgSVIP in regulating immune responses, the expression level of CgSVIP protein in haemocytes of C. gigas sig-
nificantly increased after stimulation with carbamazepine (CBZ), reaching 1.67 fold that of the DMSO group. After inhibiting
the expression of CgSVIP in C. gigas by RNAi and stimulating with LPS for 12 h, the expression levels of CgSVIP and auto-
phagy-related genes CgLC3, CgBeclin1, CgAtg5 and CgP62 in haemocytes significantly decreased, reduced to 53%, 16%,
38%, 19% and 40% of the NC-RNAi+LPS group, respectively. The ratio of CgLC3II/CgLC3I was significantly decreased in
the CgSVIP-RNAi+LPS group compared with the NC-RNAi+LPS group, reaching 0.73 fold that of the NC-RNAi+LPS group.
CgSVIP can be used as a potential biomarker for disease early warning in C. gigas, and it participates in the regulation of
immune responses by affecting autophagy in haemocytes and mediating antibacterial immune responses. Through changes in
gene expression as a biomarker, early warning of C. gigas aquaculture can be achieved to reduce mortality and production
losses caused by diseases.
Key words: Crassostrea gigas; SVIP; PAMPs; Vibrio splendidus; biomarker; cell autophagy
Corresponding authors: WANG Lingling. E-mail: wanglingling@dlou.edu.cn;
GAO Lei. E-mail: gaolei@dlou.edu.cn
Funding projects: National Natural Science Foundation of China (32230110); China Agriculture Research System of MOF
and MARA (CARS-49); Outstanding Talents and Innovative Team of Agricultural Scientific Research; Dalian Outstanding
Young Science and Technology Talent Program (2022RG14, 2024RJ010)

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
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