Peach (Prunus persica L. Batsch), a member of the Rosaceae family, is a nutritionally dense fruit rich in vitamins, amino acids, phenolic compounds, dietary fiber, and essential minerals (Kumari et al., 2023). According to 2024 data from the Food and Agriculture Organization, as the world's leading producer, China yields is over 17.51 tons of peaches and nectarine production in 2023. Beyond fresh consumption, its processing potential–for dried fruits, juices, and other derivatives–enhances its economic value (Li et al., 2021). However, throughout the postharvest chain, peaches are highly susceptible to phytopathogens. Among these, the most economically important peach diseases in China, Spain, and USA include brown rot caused by Monilinia spp., bacterial spot caused by Xanthomonas arboricola pv. pruni (Xap), Armillaria root rot, bacterial canker caused primarily by Pseudomonas syringae, and powdery mildew caused by Podosphaera pannosa (Luo et al., 2022). Brown rot, caused by the M. fructicola, is a globally devastating disease that primarily affects stone fruit crops (Cheng et al., 2023). Based on previous survey findings, M. fructicola could cause 30 % to 80 % of peach fruit rot. The damage extends beyond significant economic losses to the peach industry, posing a serious threat to the entire fruit sector due to its broad scope of infection—affecting various fruits including plums, sweet cherries, apricots, and jujubes (Huang et al., 2024). Initial symptoms manifest as small brown lesions on the fruit surface, which rapidly expand into sporodochia (gray-white to gray-brown spore masses), leading to widespread browning, softening, and putrefaction within days. This compromises fruit quality and renders infected produce unmarketable (Li et al., 2022c).

Historically, synthetic fungicides like thiabendazole and sodium o-phenylphenate have been pivotal in controlling postharvest brown rot and browning (Gianfranco et al., 2016; Lalancette et al., 2020). However, growing concerns over chemical residues, environmental toxicity, and the emergence of fungicide-resistant pathogens have accelerated the search for sustainable alternatives (Lalancette et al., 2020). Biocontrol strategies–including natural compounds and microbial derivatives–have emerged as promising solutions due to their eco-friendly profiles (Karygianni et al., 2014). Plant-derived sulfur compounds, such as allicin from garlic (Allium sativum), exhibit potent antimicrobial activity by disrupting cell membranes and inducing oxidative stress (Borlinghaus et al., 2014; Salehi et al., 2019). Despite these advantages, allicin's structural instability–owing to reactive double bonds that render it susceptible to oxidation, thermal degradation, and alkaline decomposition–limits its commercial application (Li et al., 2022a). DETS, a stable organosulfide derivative of allicin, has shown promise in postharvest disease control. Previous studies demonstrated that DETS extends the shelf life of cherry fruit (Prunus avium L.) by inhibiting Penicillium expansum, with in vitro antimicrobial efficacy dozens of times greater than allicin (Ding et al., 2020). Additionally, DETS effectively controls Botrytis cinerea-induced gray mold in strawberries (Liu et al., 2025). This study aims to: (i) Evaluate the antifungal activity of DETS against M. fructicola through in vitro (mycelial inhibition, spore germination) and in vivo (peach fruit infection assays) experiments; (ii) Elucidate the molecular mechanisms of DETS-induced inhibition through transcriptomic profiling (RNA-seq) and functional validation, focusing on fungal growth (hyphal ultrastructure), virulence factor expression (cell wall-degrading enzymes), and oxidative stress response (ROS scavenging systems); (iii) Assess the practical utility of DETS as an eco-friendly biocontrol agent for postharvest brown rot in peaches.