Integrated transcriptomic and metabolomic analysis unravels the molecular basis of conspecific aggression in Pelodiscus sinensis.

Aggressive behavior is a critical issue affecting health and survival in aquaculture animals; however, the molecular mechanism of aggression in reptiles has not been fully understood. Using the Chinese softshell turtle (Pelodiscus sinensis) as a model, we established a turtle model of reactive aggression using the intruder experiment to compare aggressive and non-aggressive individuals. Integrated brain transcriptomic and metabolomic analysis revealed enrichment in glutamatergic and GABAergic pathways between aggressive and non-aggressive individuals. Aggressive individuals showed upregulated glutamate receptor genes (GRIA2, GRIA3, GRIK3) and an altered GABAergic system. Correlation networks confirmed coordinated gene-metabolite covariation in these pathways. Drug injection tests demonstrated that NMDA receptor antagonist MK-801 significantly reduced attacks, indicating that glutamatergic signaling is a primary driver of aggressive behavior. These findings highlight conserved excitatory mechanisms in vertebrate aggression with reptile-specific characteristics and offer targets for low aggressiveness breeding in aquaculture.