Chlorogenic acid on the in vitro germination, invasion and intracellular proliferation of Ameson portunus (Microsporidia)

Ameson portunus , the causative agent of "toothpaste disease" in Portunus trituberculatus and "slurry-like syndrome" in Scylla paramamosain , has caused substantial economic losses in Chinese aquaculture. Currently, there are no effective strategies to control this pathogen. Chlorogenic acid, known for its antioxidant, anti-inflammatory, antibacterial, and antiviral properties, is widely used in aquaculture due to its safety and efficacy. This study explored its impact on the in vitro germination, invasion, and intracellular proliferation of A. portunus spores through molecular and omics analyses. Results showed that chlorogenic acid significantly inhibited spore germination in a dose-dependent manner and effectively blocked invasion and intracellular proliferation at a safe dose of 100 µg/ml. Transcriptome analysis comparing 1 µg/ml (PO), 100 µg/ml (PH), and 0 µg/ml (PZ) groups revealed that the drug suppressed spore DNA replication and key signaling pathways, including cAMP, Rap1, Ras, Wnt, ErbB, Notch, and JAK/STAT. These pathways are critical for spore proliferation, differentiation, and development. The 100 µg/ml dose demonstrated significantly greater inhibition of spore germination and invasion compared 0 to 1 µg/ml. The Ras protein in the Rap1 and Ras pathways emerged as a potential drug target. Additionally, spores upregulated genes related to ribosome, proteasome, peroxisome, and metabolic processes as a survival response to drug exposure. These findings highlight chlorogenic acid's potential as a therapeutic agent against A. portunus.