Studies have found that sodium dehydroacetate (SD) can effectively inhibit the growth of Penicillium digitatum but its inhibitory mechanism remains unclear. In this study, the antifungal mechanism of SD was analyzed by measuring the effects of different concentrations of SD on the cell structure and function (cell wall, cell membrane and mitochondria) of P. digitatum mycelia. Results showed that SD entered the cells by active transport after 30 min of treatment and intracellular SD concentration was maintained at a high level during the treatment period. Compared with the untreated control group, the fluorescence intensity of cell wall and the extracellular alkaline phosphatase (AKP) activity of SD-treated mycelial cells were not significantly different, whereas propidium iodide staining showed that SD caused a significant increase in the fluorescence intensity of mycelia (P < 0.05), decreased the total lipid content of mycelia, and increased the extracellular pH, indicating that SD treatment directly damaged the cell membrane without damaging the cell wall. SD treatment also reduced the mycelial mitochondrial membrane potential and energy charge levels and increased Na⁺/K⁺-ATPase activity, thereby disturbing cellular energy metabolism. Intervention experiments showed that SD treatment effectively inhibited the incidence of green mold of inoculated kumquat fruit in a concentration-dependent manner. The above results indicated that SD exerts its antifungal effect and reduces the incidence of green mold in postharvest kumquat fruit by damaging the structure and function of the cell membrane and mitochondria of P. digitatum mycelia. These findings can provide a theoretical basis for the application of SD in the green control of postharvest kumquat diseases.

An innovative strategy for the preparation of Zr-based metal-organic framework (MOF, UIO-67) anchored three-dimensional carboxymethyl cellulose (CMC) aerogels was developed as a flexible and efficient absorbent for the removal of the bitter compounds from ponkan wine. Field emission scanning electron microscopy (FESEM) was carried out to investigate the morphology and hierarchical structure of CMC and UIO-67/CMC aerogels. Results showed that UIO-67 was found to be uniformly distributed on CMC. UIO-67/CMC aerogels maintained the three-dimensional porous structure of CMC. The adsorption experiments showed that the adsorption equilibrium time of UIO-67/CMC aerogels was 10 min for limonin and 20 min for naringin with adsorption efficiency of 83% and 56%, respectively. The adsorption behaviors followed the pseudo-second-order kinetic and Langmuir isotherm models, indicating that the adsorption rate is governed by chemical adsorption and the adsorption process is single-layer adsorption. Treatment with UIO-67/CMC aerogels retained most of the flavor compounds in ponkan wine while improving its physicochemical properties.

This study explored the inhibitory effect and potential antifungal mechanism of α-terpineol against an imazalil-resistant strain of Penicillium digitatum Pdw03. In vitro experiment showed that α-terpineol exhibited antifungal activity against P. digitatum Pdw03, with minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of 4.00 μL/mL. In vivo results showed that α-terpineol at MFC and 5 MFC significantly reduced the incidence of green mold and lesion diameter in ponkan fruit inoculated with P. digitatum Pdw03. Propidium iodide (PI) staining indicated that 1/2 MIC α-terpineol evidently decreased the cell membrane integrity, ergosterol content (P < 0.05) and gene expression of squalene synthase (ERG9) (P < 0.05) in P. digitatum Pdw03. These results suggest that α-terpineol affects the growth of P. digitatum Pdw03 by inhibiting the gene expression of ERG9, and thus is an effective alternative for controlling postharvest citrus diseases.

In this study, the effect of citronellal on the synthesis of ergosterol in the spores of imazalil-sensitive (Pds01) and imazalil-resistant (Pdw03) strains of Penicillium digitatum was investigated. The results showed that citronellal significantly inhibited the spore germination of Pds01 and Pdw03 with half maximal inhibitory concentration (IC₅₀) of 0.8 and 3.2 µL/mL, respectively. Citronellal at its IC₅₀ significantly decreased and increased the contents of ergosterol and lanosterol in Pds01 and Pdw03 spores, respectively. The expression of key genes involved in ergosterol synthesis was significantly affected. The up-regulated expression of the ERG9 gene in Pds01 peaked earlier than that in Pdw03, and the expression level of ERG3 was significantly down-regulated in both strains. This study showed that citronellal reduced ergosterol synthesis in Pds01 and Pdw03 spores by inhibiting ERG3 expression, thereby affecting spore germination, which could provide a theoretical basis for the development of green preservatives for postharvest citrus diseases.

Pleurotus geesteranus, being rich in nutrients and moisture, easily loses water and wilts after harvest, reducing its commercial value. Furthermore, film packaging leads to excessive humidity in the internal environment, causing products to decay. In this study, polylactic acid (PLA) and chitosan (CS) were used as film-forming substrates to prepare a one-way moisture barrier bilayer film containing 0.25% cinnamaldehyde nano-emulsion (CANE). The microstructure, physical properties, optical properties, mechanical properties, moisture barrier properties and sustained release behavior of the film were investigated and its application in the preservation of P. geesteranus was evaluated. The results showed that the combination between PLA and CS could effectively make up for the defects of the monomer film, and the layers in the composite film with 0.25% CANE were tightly bound to each other, with a retention rate of 42% for cinnamaldehyde (CA). The film had strong ultraviolet resistance and the smallest settling speed of water droplets. The P layer had good water vapor barrier properties, and the C layer had good hydrophilicity. Compared with polyethylene (PE) film packaging, the 0.25% CANE-PLA-CS bilayer film significantly inhibited the browning and respiratory intensity of P. geesteranus during postharvest storage, delayed the increase in mass loss, soluble solids content, browning degree, electrical conductivity and malondialdehyde (MDA) content, reduced the activities of polyphenol oxidase (PPO) and peroxidase (POD) and maintained higher superoxide dismutase (SOD) activity. These results indicated that the one-way moisture barrier bilayer film could effectively delay the browning and aging of P. geesteranus and maintain its commercial value. This study provides theoretical support for the preparation of novel packaging materials for mushrooms and is of guiding significance to the reduction of post-harvest loss of P. geesteranus.