Integrated analysis of fresh peach fruit during Penicillium expansum infections.

BACKGROUND Penicillium expansum is a major peach fruit pathogen that causes significant economic losses worldwide. It produces patulin, a mycotoxin that poses severe health risks to humans. Studies of disease infection mechanisms in fruits during fungal infection help to understand how pathogens colonize and trigger disease, enabling the development of alternative disease control strategies. In this study, we investigated the disease infection mechanism of P. expansum in fresh peaches. RESULTS Penicillium expansum can infect peaches in <24 h and fully colonize the fruit at 36 h. During the first 24-48 h, the activities of disease-defense-related enzymes such as polygalacturonase, chitinase, polyphenol oxidase, phenylalanine ammonia-lyase, and peroxidase were significantly increased and then declined after the pathogen colonization. Transcriptome analysis of peach fruit at 36 h postinfection identified 2884 differentially expressed genes, with 399 upregulated and 2445 downregulated genes. The expression of key genes such as ANP1, BGL, CAD, CDPK, G6PDH/Glc6PD, GST, PP2C, TCH4 and GGCT were lower, whereas the expression of HCT and PFK genes were higher. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis also confirmed that P. expansum disrupted several cellular functions and key metabolic pathways of the fruit. CONCLUSION Penicillium expansum can fully colonize fresh peach fruit at 36 h, and control measures should be taken before that. The pathogen alters enzymatic activities and disrupts gene and metabolic pathways of peaches. Control strategies such as enhancing the fruit's resistance using biotechnology should consider the molecular changes identified. © 2025 Society of Chemical Industry.