Identification of ATG genes in the noble scallop Chlamys nobilis reveals unique expression strategies against low-temperature and Vibrio parahaemolyticus challenge.

Abstract

Autophagy is a highly conserved cellular degradation pathway in eukaryotes, orchestrated by a suite of autophagy-related (ATG) genes. Beyond their canonical autophagic roles, ATG proteins participate extensively in diverse non-autophagic processes, serving as crucial regulators for cellular homeostasis and normal physiological functions. The noble scallop, Chlamys nobilis, is an economically important mariculture bivalve in southern China, yet its aquaculture industry frequently suffers severe losses due to extremes low temperature events and bacterial diseases. However, the evolutionary characteristics and stress-resistance functions of the ATG genes in this species remain poorly understood. In this study, a total of 213 non-redundant ATG genes were identified from 12 bivalve species and classified into 16 subfamilies, among which the ATG4 and ATG8 subfamilies exhibited extensive gene duplication. In C. nobilis, 17 CnATG genes were identified, spanning 14 subfamilies. Tissue expression profiling revealed that most CnATG genes were highly expressed in the kidney, intestine, and gill tissues. Importantly, low-temperature stress and Vibrio parahaemolyticus challenge experiments demonstrated markedly distinct expression patterns of CnATG genes, indicating their involvement in different stress response programs mediated by sophisticated transcriptional regulatory networks. This study systematically elucidates the evolutionary characteristics and expression regulation patterns of ATG genes in C. nobilis, laying a solid foundation for dissecting the mechanisms of environmental adaptation and immune defense in this scallop, and providing a valuable reference for autophagy-related research in other bivalves.