New insights into the adaptation mechanism of Cardisoma armatum hepatopancreas in the terrestrial environment by transcriptome analysis.

Abstract

As a typical species of Gecarcinidae, Cardisoma armatum has adapted to the terrestrial environment. Meanwhile, C. armatum with unique living habits provides an excellent model for exploring the terrestrial adaptation mechanism of crabs. In this study, we have conducted a comprehensive transcriptomic analysis of C. armatum, aiming to deepen our understanding of the adaptive mechanisms operating within two groups: the air-exposed (AE) group and the water-immersed (WI) group, over eight hours. Genes that showed differential expression about adaptation to terrestrial environments were categorized into three groups: immune regulation, antioxidant system, and ion transport. The transcriptomic analysis also revealed a significant increase in the expression of genes related to immune response, antioxidant systems, and ion transport, such as the mitogen-activated protein kinase signaling pathway, tumor protein 53, superoxide dismutase 1, superoxide dismutase 2, solute carrier family 9 member A3, and Na⁺/K⁺/2Cl^- cotransporter, indicating that C. armatum responds positively to changes in habitat. This study aims to furnish a molecular rationale for the adaptive mechanisms that terrestrial and semi-terrestrial crab species exhibit in their terrestrial habitats, thereby contributing to a deeper understanding of their evolutionary adaptations.