Expansum Spores Research Articles

Functionalized chalcogenide thin films for early detection of plant diseases via spore detection

This study investigates the functionalization of Ge-Se-Te chalcogenide thin films using various organosilane precursors, including TEOS, OTES, APTES, ImPTES and MPTMS, to render them more hydrophilic or hydrophobic, or impart surface charges. The integrity of the deposited hybrid layers was confirmed by proton Nuclear Magnetic Resonance spectroscopy after alkaline depolymerization of test samples. The modified surfaces were characterized by Water Contact Angle measurements, Scanning Electron Microscopy and Atomic Force Microscopy. The ability of these functionalized surfaces to immobilize individual or mixed spores of two different varieties, Venturia inaequalis and Penicillium expansum, both responsible for fruit tree diseases, was evaluated. The two spore varieties behaved similarly, whether alone or mixed. Neither spore variety adhered to very hydrophilic surfaces. While the percentage of immobilized Venturia inaequalis spores increased with the surface hydrophobicity, Penicillium expansum spores were not immobilized on highly hydrophobic surfaces. Venturia inaequalis spores, characterized by a very negative zeta potential, were very well immobilized on positively charged surfaces. Consequently, the best immobilization percentage for this spore variety was obtained for the surface functionalized with ImPTES, a precursor characterized by a stable positive charge of imidazolium group. Penicillium expansum spores were less sensitive to positive charges due to their less negative zeta potential. The highest immobilization percentage for this spore variety was obtained with the precursor TEOS. One explanation could be the formation of hydrogen bonds.

Feruloyl Glyceride Mitigates Tomato Postharvest Rot by Inhibiting Penicillium expansum Spore Germination and Enhancing Suberin Accumulation.

Postharvest rot, caused by Penicillium expansum, in tomatoes poses significant economic and health risks. Traditional control methods, such as the use of fungicides, raise concerns about pathogen resistance, food safety, and environmental impact. In search of sustainable alternatives, plant secondary metabolites, particularly phenolic compounds and their derivatives, have emerged as promising natural antimicrobials. Among these, feruloyl glyceride (FG), a water-soluble derivative of ferulic acid, stands out due to its antioxidant properties, antibacterial properties, and improved solubility. In this study, we provide evidence demonstrating FG is capable of inhibiting the spore germination of P. expansum and effectively reducing the incidence rate of Penicillium rot of tomatoes, without compromising quality. Electron microscopy observations combined with metabolite and transcriptomic analyses revealed that FG treatments resulted in enhanced suberin accumulation through promoting the expression of suberin synthesis related genes and, consequently, inhibited the growth and expansion of P. expansum on the fruits. This work sheds light on the mechanisms underlying FG's inhibitory effects, allowing its potential application as a natural and safe alternative to replace chemical fungicides for postharvest preservation.

Study of kinetic model for fungal spore germination under dynamic conditions: Case study on germination of Penicillium expansum spores

The germination of fungal spores under non-isothermal conditions has been studied for several years, however, no mathematical model has been able to describe them suitably. Therefore, in this paper, we developed a new model to clarify the understanding of fungal spore germination under non-isothermal conditions by considering the effects of magnitude of condition change and difference in phase of spore during condition change on kinetic parameters, i.e., the mean rate of germination (μ) and the time that half of spores had germinated (th). To combine both effects into our new model, it was necessary to develop other two new models. The first model was used for estimating the swelling time of spores. The second model was the relationship between thvs μ. After we had completed both models and successfully combined both effects into the new model for fungal spore germination under non-isothermal conditions, the new model was validated against experimental data on germination of Penicillium expansum spores in the literature. The prediction results showed that the new model well described the germination of this fungus under non-isothermal conditions.

Principal antifungal factors and underlying mechanisms of dielectric barrier discharge plasma against Penicillium expansum spores as well as its application in kiwi-fruit juice

The objective of this work was to investigate the main antifungal factors and mechanisms of dielectric barrier discharge (DBD) plasma against Penicillium expansum spores. The application in kiwi-fruit juice was also studied. The results showed that 240 s was adequate for an about 6.0 log10 reduction of survival spores in kiwi-fruit juice after plasma treatment at 18 kV. DBD plasma treatment resulted in slight changes in pH, total phenolics, and color parameters of kiwi-fruit juice, but did not affect the total soluble solid and vitamin C contents. Among the longer-lived species generated by DBD plasma, NO2− was demonstrated to be related with the inactivation of P. expansum spores, but not considered as the important agent. Additionally, short-lived species (such as ∙OH, O2∙−, and 1O2) were confirmed to exist in the plasma-water system by electron spin resonance spectroscopy. Thereinto, O2∙− and 1O2 contributed the most to the inactivation. Both species caused the morphologic alteration, membrane disruption, intracellular substance leakage, and DNA damage of spores. In conclusion, DBD plasma can effectively inactivate P. expansum spores in kiwi-fruit juice, which is mainly due to the disruption of cell membrane and DNA damage induced by O2∙− and 1O2 derived from DBD plasma.

Would You Like Wood or Plastic? Bin Material, Sanitation Treatments, and Bin Inoculum Levels Impact Blue Mold Decay of Stored Apple Fruit.

Blue mold, caused primarily by Penicillium expansum, is a significant postharvest disease of apples. It not only causes economic losses but also produces mycotoxins that contaminate processed fruit products, which contributes to food waste and loss. Previous research has shown that packing and storage bins harbor Penicillium spores and that steam and hot water efficiently reduce spore inoculum levels. However, studies using wooden and plastic bins regarding their ability to harbor spores, the effect of chemical sanitation treatments on spore levels, and the impact of rinsate from treated bins on apple fruit decay have not been investigated for the Mid-Atlantic area (Okull et al. 2006; Rosenberger 2009). We evaluated different sanitation treatments (chemical and physical) to reduce P. expansum inoculum levels on wooden and plastic bins. We determined that wooden bins bound P. expansum spores four orders of magnitude higher than plastic. When both bin types were treated with steam (wooden) or sterile hot water (plastic), Thyme Guard, or Academy, all treatments resulted in significantly (P < 0.05) lower spore levels compared to untreated controls. Although, plastic bins retained lower numbers of spores after inoculation with contaminated spore rinsate and required much higher concentrations of P. expansum spores in rinsate to retain spores at levels that would lead to decay on apple fruit. Overall, we demonstrated that plastic bins retain fewer spores than wooden bins and that both can be sanitized by various physical or chemical treatments. We envision that our findings will be applicable in the future as the techniques implemented in this study were used to investigate industry-relevant questions. Our goal is that the research techniques and findings become feasible with advancements in technology and/or accompany other shifts in existing processes in commercial pome fruit packing and storage facilities.

Inactivation of Penicillium expansum spores in apple juice by contact glow discharge electrolysis and its related mechanism

Penicillium expansum spores in apple juice were treated with contact glow discharge electrolysis (CGDE), and the effect of different parameters on the efficiency of spore inactivation and the related mechanism were investigated. We found that CGDE effectively inactivated spores of P. expansum in the clarified apple juice. CGDE achieved a 3.71 log inactivation of spores in the juice with 1 cm electrode gap, at 520 V, and discharge time for 15 min. CGDE produced hydrogen peroxide in the juice, and the concentration reached 58.1 mg/L after discharged for 30 min. CGDE destroyed the integrity of the cell membrane in the spores, and reduced the activities of superoxide dismutase, catalase, and peroxidase by 68.1%, 81.8%, and 68.0% after discharged for 30 min. In addition, CGDE inhibited mycelial growth, reduced colony diameter by 18.9%, and decreased the lesion diameter by 41.4% in apples surface-inoculated with P. expansum. Taken together, CGDE could inactivate the spores of P. expansum in apple juice by inducing reactive oxygen species accumulation and disrupting the integrity of cell membrane of spores. Industrial relevanceCGDE can effectively inactivate the spores of P. expansum in apple juice. The device of CGDE is composed of a high voltage DC power supply, electrodes and a reaction vessel, which is connected easily with material pipeline, and suitable for handling liquids. Therefore, CGDE can be applicated in treating liquids contaminated with fungal spores in the food industry.

Bacterial Quorum-Quenching Lactonase Hydrolyzes Fungal Mycotoxin and Reduces Pathogenicity of Penicillium expansum-Suggesting a Mechanism of Bacterial Antagonism.

Penicillium expansum is a necrotrophic wound fungal pathogen that secrets virulence factors to kill host cells including cell wall degrading enzymes (CWDEs), proteases, and mycotoxins such as patulin. During the interaction between P. expansum and its fruit host, these virulence factors are strictly modulated by intrinsic regulators and extrinsic environmental factors. In recent years, there has been a rapid increase in research on the molecular mechanisms of pathogenicity in P. expansum; however, less is known regarding the bacteria–fungal communication in the fruit environment that may affect pathogenicity. Many bacterial species use quorum-sensing (QS), a population density-dependent regulatory mechanism, to modulate the secretion of quorum-sensing signaling molecules (QSMs) as a method to control pathogenicity. N-acyl homoserine lactones (AHLs) are Gram-negative QSMs. Therefore, QS is considered an antivirulence target, and enzymes degrading these QSMs, named quorum-quenching enzymes, have potential antimicrobial properties. Here, we demonstrate that a bacterial AHL lactonase can also efficiently degrade a fungal mycotoxin. The mycotoxin is a lactone, patulin secreted by fungi such as P. expansum. The bacterial lactonase hydrolyzed patulin at high catalytic efficiency, with a kcat value of 0.724 ± 0.077 s−1 and KM value of 116 ± 33.98 μM. The calculated specific activity (kcat/KM) showed a value of 6.21 × 103 s−1M−1. While the incubation of P. expansum spores with the purified lactonase did not inhibit spore germination, it inhibited colonization by the pathogen in apples. Furthermore, adding the purified enzyme to P. expansum culture before infecting apples resulted in reduced expression of genes involved in patulin biosynthesis and fungal cell wall biosynthesis. Some AHL-secreting bacteria also express AHL lactonase. Here, phylogenetic and structural analysis was used to identify putative lactonase in P. expansum. Furthermore, following recombinant expression and purification of the newly identified fungal enzyme, its activity with patulin was verified. These results indicate a possible role for patulin and lactonases in inter-kingdom communication between fungi and bacteria involved in fungal colonization and antagonism and suggest that QQ lactonases can be used as potential antifungal post-harvest treatment.

Use and Efficiency of Disinfectants within a Hydrocooler System for Postharvest Disease Control in Sweet Cherry

ABSTRACT Commercial disinfectants were used within a hydrocooler to prevent postharvest diseases of sweet cherries and to extend the storage and shelflife durations. Different concentrations of sodium hypochlorite, peracetic acid, hydrogen peroxide and Citrox® were used in in vitro experiments whereby the toxicity of disinfectants on B. cinerea and P. expansum spore germination and germ tube elongation was investigated. Citrox® was the only disinfectant containing organic acids and flavonoids. The in vitro experiments demonstrated that disinfectants were effective in inhibiting spore germination and germ tube elongation. In in vivo experiments, fruits were inoculated with a suspension containing 1 × 106 cfu/mL B. cinerea and P. expansum spores and hydrocooled with appropriate disinfectant concentrations. Total microbial, fungal, and bacterial populations on fruit surfaces and in the water used for processing were reduced by all disinfectant applications. Fruits were packed in modified atmosphere packages and stored at 1°C for 30 days and for 4 additional days on a shelf at 20°C. During cold storage, fruits were evaluated in terms of phytotoxicity, and it was observed that Citrox®, hydrogen peroxide, and ozonated water applications cause phytotoxicity in the both the stem and fruit. In contrast, no phytotoxic reaction was observed in sodium hypochlorite and peracetic acid applications. Fruit decay did not occur during cold storage but was seen during the shelflife period. Fruit decay was significantly reduced by sodium hypochlorite and peracetic acid applications. Sodium hypochlorite and peracetic acid applications within a hydrocooler were found to be efficient in preventing postharvest diseases of sweet cherries.

Antifungal effect and possible mechanism of curcumin mediated photodynamic technology against Penicillium expansum

Abstract Contamination of Penicillium expansum has dramatic impacts on the development of the fruit and vegetable industry. In this study, the antifungal effect and its mechanism of curcumin mediated photodynamic technology (PDT) against P. expansum spores was investigated. Results indicated that PDT inactivated 99.7 % spores and inhibited spore germination, mycelial growth and disease severity of the blue mold rot on apple fruit. PDT induced the generation of reactive oxygen species (ROS), which caused oxidative damage of spores and further disrupted cellular structure. In addition, excessive ROS triggered the antioxidant defense systems of spores. Moreover, ultimate result of cell death induced by PDT was apoptosis for short time illumination, and necrosis for long time. These results can be an asset to exploit PDT for further application in controlling harvest diseases of the fruit and vegetable.

Photoelectrocatalytic inactivation of Penicillium expansum spores on a Pt decorated TiO2/activated carbon fiber photoelectrode in an all-solid-state photoelectrochemical cell

An electrode is fabricated using nanosized TiO2 on an activated carbon fiber initially ion sputtered by Pt (TiO2/ACF + Pt). An all-solid-state photoelectrochemical (ASPEC) cell using the electrode and a solid electrolyte is evaluated by photoinactivation of Penicillium expansum spores. The data analysis indicated that the Weibull model more accurately estimates the inactivation. The ASPEC cell shows a synergetic effect on the inactivation of the spores in the photoelectrocatalytic process with a 1log10 reduction time of the model rate constant of 4.37 × 10−3 min−1, with 3.87 × 10−3 and 4.49 × 10−4 min−1 for the photocatalytic and electrochemical processes, respectively. X-ray photoelectron spectroscopy shows that the Pt on the TiO2 of the electrode exists as metallic platinum, PtO and PtO2. The surface sensitization of TiO2 by PtO and PtO2 enhances the absorption of ultraviolet light. The enhanced charge separation was demonstrated by electrochemical impedance spectroscopy and transient photocurrent response. TiO2/ACF + Pt electrode illustrated more photoelectrocatalytic activity than the no Pt ion electrode. This synergetic effect could be attributed to the structures of the ASPEC cell and the interconnection with the separation of photogenerated electron-hole pairs under an electrical bias. The obtained results present a promising potential for the treatment of the spores in cold-storage environments.

Uncovering proteomics changes of Penicillium expansum spores in response to decanal treatment by iTRAQ

Exogenous decanal can significantly inhibit the germination and development of postharvest pathogen Penicillium expansum in vitro. Through an iTRAQ-based analysis, a global view of proteomic alteration of P. expansum spores under decanal treatment was acquired. A total of 246 up-regulated and 293 down-regulated differentially expressed proteins (DEPs) were identified. Among them, DEPs related to glutathione metabolism, ribosome, and oxidative phosphorylation pathway were noticed for their functional significance, large number and high rich value in pathway enrichment statistics. Further analysis found that, under decanal stress, expression of 9 genes corresponding to DEPs involved in the oxidative phosphorylation pathway showed a significantly decreasing trend, and activities of 3 crucial enzymes (NADH dehydrogenase, CoQ-Cytochrome c reductase, and F(1)F(0)-ATP synthetase) were inhibited. Also, a decreased in ATP content, reduction in the number of mitochondria, and weakening in carbohydrate consumption were detected. Based on these results, disturbance of oxidative phosphorylation would partly be responsible for the inhibitory effect of decanal on the growth of P. expansum. The findings would provide new insights into exploring the possible antifungal mechanisms of decanal.

A comparative study on the inactivation of Penicillium expansum spores on apple using light emitting diodes at 277 nm and a low-pressure mercury lamp at 253.7 nm

A comparative study was performed to assess the efficacy of UV-C light emitting diodes (UV–C LEDs) at 277 nm and a low-pressure mercury (LPM) lamp at 253.7 nm to inactivate Penicillium expansum spores on apple skin at 4 °C or 25 °C. In saline solution, the D value for the inactivation of spores using 277 nm at 25 °C was 6.62 mJ cm−2 and 7.19 mJ cm−2 at 4 °C, both of which were significantly lower than the D value at 253.7 nm (9.26 mJ cm−2). The UV-mediated inactivation of spores on the surface of apple skin followed non-linear kinetics with an initial linear phase followed by tailing. The calculated D values for spores on apple surface were significantly higher compared to within saline (14.49 and 18.80 mJ cm−2 with 277 nm at 25 °C and 4 °C, respectively, compared to 23.00 mJ cm−2 with 253.7 nm). This could be due to protective effects of apple peel constituents or the non-uniform energy distribution due to the uneven apple surface. Yet, the log reductions achieved (>2 log CFU) were equivalent to washing in hypochlorite solution (200 mg L−1 free-chlorine) which is the current industrial practice. UV-C light at 277 and 253.7 nm (500 mJ cm−2) was shown to prevent growth of blue mould and subsequent spoilage of inoculated and stored apples (28 days) if treated prior to damage. The UV-C treatments at doses corresponding to reduction of 2 log CFU of P. expansum did not impact apple physico-chemical quality parameters during 12 weeks of storage at 25 °C.

Modelling the effect of betel leaf essential oil on germination time of Aspergillus flavus and Penicillium expansum spore population

The objective of this study was to model the efficacy of betel leaf (Piper betle L.) essential oil (BLEO) on germination of Aspergillus flavus and Penicillium expansum spore population. Experimental data of rate of spore germination under the influence of the range (0.1–1.5 μl/ml) of BLEO concentration were fitted to the asymmetric model, and the germination time parameter was estimated with satisfactory statistical indices (RMSE and R2). The secondary modelling of germination time as a function of BLEO using the reciprocal of re-parameterized Monod-type equation estimated minimum inhibitory concentration 0.65 and 0.54 μl/ml of BLEO for spore germination of A. flavus and P. expansum, respectively. The accuracy and bias factor of the fitted secondary model suggested good similarity between observed and estimated germination time values under the influence of BLEO for both selected moulds. It can be concluded that the asymmetric model and the re-parameterized Monod-type model could describe the inhibitory pattern of the essential oil against two selected predominant food spoilage moulds. The antifungal activity also suggests the potential of BLEO as natural antimicrobials.

Penicillium expansum Inhibition on Bread by Lemongrass Essential Oil in Vapor Phase

The antimicrobial activity of lemongrass (Cymbopogon citratus) essential oil (EO) in the vapor phase on the growth of Penicillium expansum inoculated on bread was evaluated, followed by a sensory evaluation of the bread's attributes after EO exposure. The lemongrass EO was extracted from dry leaves of lemongrass by microwave-assisted steam distillation. The chemical composition of the lemongrass EO was determined using a gas chromatograph coupled to a mass spectrometer. The refractive index and specific gravity of the EO were also determined. Bread was prepared and baked to reach two water activity levels, 0.86 or 0.94, and then 10 μL of P. expansum spore (106 spores per mL) suspension was inoculated on the bread surface. Concentrations of lemongrass EO were tested from 125 to 4,000 μL/Lair, whereas mold radial growth was measured for 21 days. For sensory evaluation, breads were treated with lemongrass EO vapor at 0, 500, or 1,000 μL/Lair for 48 h and tested by 25 untrained panelists. The EO yield was 1.8%, with similar physical properties to those reported previously. Thirteen compounds were the main components in the EO, with citral being the major compound. P. expansum was inhibited for 21 days at 20°C with 750 μL of EO/Lair, and its inhibition increased with increasing concentrations of EO. Sensory acceptance of bread exposed to vapor concentrations of 500 or 1,000 μL of EO/Lair or without EO was favorable; similar and no significant differences (P > 0.05) were observed among them.

Identification of differentially expressed genes involved in spore germination of Penicillium expansum by comparative transcriptome and proteome approaches.

In this study, Penicillium expansum, a common destructive phytopathogen and patulin producer was isolated from naturally infected apple fruits and identified by morphological observation and rDNA‐internal transcribed spacer analysis. Subsequently, a global view of the transcriptome and proteome alteration of P. expansum spores during germination was evaluated by RNA‐seq (RNA sequencing) and iTRAQ (isobaric tags for relative and absolute quantitation) approaches. A total of 3,026 differentially expressed genes (DEGs), 77 differentially expressed predicted transcription factors and 489 differentially expressed proteins (DEPs) were identified. The next step involved screening out 130 overlapped candidates through correlation analysis between the RNA‐seq and iTRAQ datasets. Part of them showed a different expression trend in the mRNA and protein levels, and most of them were involved in metabolism and genetic information processing. These results not only highlighted a set of genes and proteins that were important in deciphering the molecular processes of P. expansum germination but also laid the foundation to develop effective control methods and adequate environmental conditions.

EVALUATION OF THE ANTIFUNGAL ACTIVITIES OF THREE ESSENTIAL OIL COMPONENTS AGAINST PENICILLIUM EXPANSUM SPORES

Objective: The aim of the present study was to evaluate the antifungal potential of β-Ionone; carvone and 1,8-cineole which are three essential oil components.Methods: For that purpose, the minimum inhibitory (MIC) and fungicidal (MFC) concentrations of these compounds were determined by the microdilution method using the 96 well microtiter plates. The efficiency of these compounds was tested against the spores of Penicillium expansum; a strain responsible for huge post-harvest losses during storage of fruits and capable of producing patulin, a very dangerous mycotoxin for the human health.Results: The obtained results showed a very strong inhibition of the growth of P. expansum spores with very low MIC values determined for β-Ionone (0.625 %); Carvone (0.3125 %) and 1,8-cineol (0.078125 %). In addition, the evaluation of MFCs for the tested essential oil components showed that β-Ionone and carvone molecules exhibited the same MFCs at 5 % against P. expansum spores. However, the best fungicidal activity was found with the 1,8-cineole molecule at a concentration of 1.25 % vis-à-vis of the spores of this strain.Conclusion: This study, which shows for the first time the antifungal potential of these three molecules against this strain, also allows to highlight the possibility of using these essential oil compounds in the formulation of commercial antifungal products.

The response of growth and patulin production of postharvest pathogen Penicillium expansum to exogenous potassium phosphite treatment

In this study, the effects of exogenous potassium phosphite (Phi) on growth and patulin production of postharvest pathogen Penicillium expansum were assessed. The results indicated that P. expansum under 5mmol/L Phi stress presented obvious development retardation, yield reduction of patulin and lower infectivity to apple fruit. Meanwhile, expression analysis of 15 genes related to patulin biosynthesis suggested that Phi mainly affected the early steps of patulin synthetic route at transcriptional level. Furthermore, a global view of proteome and transcriptome alteration of P. expansum spores during 6h of Phi stress was evaluated by iTRAQ (isobaric tags for relative and absolute quantitation) and RNA-seq (RNA sequencing) approaches. A total of 582 differentially expressed proteins (DEPs) and 177 differentially expressed genes (DEGs) were acquired, most of which participated in carbohydrate metabolism, amino acid metabolism, lipid metabolism, genetic information processing and biosynthesis of secondary metabolites. Finally, 39 overlapped candidates were screened out through correlational analysis between iTRAQ and RNA-seq datasets. These findings will afford more precise and directional clues to explore the inhibitory mechanism of Phi on growth and patulin biosynthesis of P. expansum, and be beneficial to develop effective controlling approaches based on Phi.

Postharvest Disease Control of Colletotrichum gloeosporioides and Penicillium expansum on Stored Apples by Gamma Irradiation Combined with Fumigation.

To study the control of postharvest decay caused by Colletotrichum gloeosporioides and Penicillium expansum, gamma irradiation alone or in combination with fumigation was evaluated to extend the shelf life of apples in South Korea. An irradiation dose of 2.0 kGy resulted in the maximum inhibition of C. gloeosporioides and P. expansum spore germination. The gamma irradiation dose required to reduce the spore germination by 90% was 0.22 and 0.35 kGy for C. gloeosporioides and P. expansum, respectively. Microscopic observations revealed that when the fungal spores were treated with gamma irradiation (4.0 kGy), conidial germination was stopped completely resulting in no germ tube formation in C. gloeosporioides. Treatment with the eco-friendly fumigant ethanedinitrile had a greater antifungal activity against C. gloeosporioides and P. expansum in comparison with the non-treated control under in vitro conditions. The in vitro antifungal effects of the gamma irradiation and fumigation treatments allowed us to further study the effects of the combined treatments to control postharvest decay on stored apples. Interestingly, when apples were treated with gamma irradiation in combined with fumigation, disease inhibition increased more at lower (< 0.4 kGy) than at higher doses of irradiation, suggesting that combined treatments reduced the necessary irradiation dose in phytosanitary irradiation processing under storage conditions.

Evaluation of Hydrophobic-hydrophilic Properties and Anti-adhesive Potential of the Treated Cedar Wood by Two Essential Oil Components Against Bioadhesion of Penicillium expansum Spores

Evaluation of Hydrophobic-hydrophilic Properties and Anti-adhesive Potential of the Treated Cedar Wood by Two Essential Oil Components Against Bioadhesion of Penicillium expansum Spores

Dissecting inhibitory effect of boric acid on virulence and patulin production of Penicillium expansum

Pencillium expansum, the causal agent of blue mould rot, is one of the most destructive postharvest pathogens of pome fruit. It is also considered as the main source of the mycotoxin patulin which can lead to serious health problems. In the present study, the effects of exogenous boric acid (BA) on virulence and patulin production of P. expansum were evaluated. The results showed that 0.3% BA significantly inhibited the development of P. expansum in vitro and resulted in lower virulence to apple fruit. Moreover, BA suppressed the metabolism of carbohydrate, lipid and protein, reduce patulin production in P. expansum. Further analysis revealed that the expressions of the majority of the 15 genes involved in patulin biosynthesis were down-regulated under BA treatment. In addition, a global view of proteome alteration of P. expansum spores in response to 0.3% BA was acquired by an iTRAQ-based (Isobaric tags for relative and absolute quantitation) quantitative proteomic analysis. A total of 315 differentially expressed proteins (DEPs) (87 up-regulated and 228 down-regulated) were identified, and these DEPs were mainly involved in carbohydrate and protein metabolic pathways. Among them, septins and proteins related to ribosome component or ribosome biosynthesis were noticed for their significant up-regulation. Our results provided novel information for understanding the mechanism, by which BA regulated the growth of P. expansum and its virulence.