Postharvest Fruit Decay Research Articles

Biocontrol potential of Burkholderia gladioli STPT16 on postharvest decay of litchi fruit caused by Peronophythora litchii and Colletotrichum fructicola

Litchi downy blight (LDB) caused by Peronophythora litchii and anthracnose (AD) caused by Colletotrichum species are major pre- and postharvest disease of litchi fruit. Biocontrol agents such as Burkholderia has been applied for controlling postharvest fruit decay. In this work, an endophytic strain SZPT16 isolated from health litchi branch was identified as Burkholderia gladioli and exhibited strong antagonistic activity against mycelial growth and conidia/sporangia germination of two postharvest pathogens. Dual incubation of pathogen and biocontrol agents caused alterations in hyphal and conidial/sporangial structures and severe cell morphology changes such as mycelia deformation, cell wall collapse and cellular disorganization. Cell-free culture filtrates (CF, diluted at 25-fold) of B. gladioli SZPT16 showed an efficient inhibition on postharvest litchi decay by preharvest application (74.77 % protection) and postharvest application (64.68 % and 71.14 % protection for LDB and AD, respectively). Furthermore, UPLC-MS/MS metabolomic analysis identified 41 up-regulated differential metabolites, which mainly included nucleosides, nucleotides, and analogues, organic acids and derivatives, organic oxygen compounds, and organoheterocyclic compounds. This study firstly reported the efficacy of CF of B. gladioli SZPT16 in protecting postharvest litchi fruit against natural and inoculated pathogen infections. The overall results provide a promising alternative to chemical fungicides to control litchi postharvest decay.

Novel Essential Oil-Based Thiosemicarbazone Compounds as Potential Fungicides in Controlling Postharvest Diseases of Citrus Fruit.

To develop novel fungicides for controlling postharvest fungal diseases in citrus fruits, 12 essential oil (EO)-based thiosemicarbazones compounds, termed hydrazine-carbothioamide, were prepared according to the condensation method. In vitro assays showed that compound 13j exhibited the strongest antifungal activity (minimum inhibitory concentration [MIC] = minimum fungicidal concentration [MFC] = 0.0125 mg/mL) against Penicillium digitatum. An in vivo study revealed that 5 × MFC of compound 13j can effectively mitigate the green mold incidence of citrus fruit inoculated with P. digitatum, as well as fruit rot during natural storage, at a level comparable to that of the chemical fungicide prochloraz. Throughout this process, fruit quality was maintained. The hemolysis assay showed that these thiosemicarbazone compounds have good biocompatibility and that their safety is comparable to that of prochloraz. The antifungal activity of compound 13j was attributed to membrane damage, as confirmed using scanning electron microscopy (SEM), Calcofluor white (CFW) staining, propidium iodide (PI) staining, Fourier transform-infrared (FT-IR) spectroscopy, optical density (OD)260, and relative conductivity assays. Collectively, our results indicate that compound 13j can be used as an antifungal agent to control the postharvest decay of citrus fruits.

Isolation of Antagonistic Endophytic Fungi from Postharvest Chestnuts and Their Biocontrol on Host Fungal Pathogens.

In this study, antagonistic endophytic fungi were isolated from postharvest chestnut fruits; endophytic antagonistic fungi and their combination of inhibitory effects on the fungal pathogen Neofusicoccum parvum were evaluated. A total of 612 endophytic fungi were isolated from 300 healthy chestnut kernels, and 6 strains out of them including NS-3, NS-11, NS-38, NS-43, NS-56, and NS-58 were confirmed as antagonistic endophytic fungi against Neofusicoccum parvum; these were separately identified as Penicillium chermesinum, Penicillium italicum, Penicillium decaturense, Penicillium oxalicum, Talarmyces siamensis, and Penicillium guanacastense. Some mixed antagonistic endophytic fungi, such as NS-3-38, NS-11-38, NS-43-56, and NS-56-58-38, exhibited a much stronger antifungal activity against N. parvum than that applied individually. Among them, the mixture of NS-3-38 showed the highest antifungal activity, and the inhibition rate was up to 86.67%. The fermentation broth of NS-3, NS-38, and their combinations exhibited an obvious antifungal activity against N. parvum, and the ethyl acetate phase extract of NS-3-38 had the strongest antifungal activity, for which the inhibitory rate was up to 90.19%. The NS-3-38 fermentation broth combined with a chitosan coating significantly reduced N. parvum incidence in chestnuts from 100% to 19%. Furthermore, the fruit decay and weight loss of chestnuts during storage were significantly decreased by the NS-3-38 fermentation broth mixture along with a chitosan coating. Therefore, a mixture of P. chermesinum and P. decaturense could be used as a potential complex biocontrol agent to control postharvest fruit decay in chestnuts.

Postharvest biocontrol ability and antagonistic mechanism of Bacillus altitudins h217 against Penicillium digitatum in citrus

Penicillium digitatum is the main fungi causing postharvest decay of citrus fruits. In this study, the strain h217 was identified as Bacillus altitudins and it showed strong biocontrol activity against P. digitatum in citrus. In vitro tests, B. altitudins h217 can effectively inhibit the growth of P. digitatum and form an inhibitory region with a diameter of 52.79 mm in PDA plate. It can also effectively delay the occurrence of P. digitatum, and reduce the incidence rate and the severity of P. digitatum in vivo. In addition, B. altitudins h217 could produce volatile organic compound (VOCs), and its VOCs have an inhibitory rate of 76.83% against P. digitatum. Three possible antifungal substances (5-methyl-2-hexanone, methoxy-phenyl oxime and 2-pentylfuran) were identified through gas chromatography-mass spectrometry (GC-MS). Acetophenone oxime (alternative compounds of methoxy-phenyl oxime) was selected for antifungal tests in vitro and in vivo, which confirmed its antifungal activity. Fluorescence staining experiments showed that B. altitudins h217 can severely damage the cell membrane of P. digitatum and cause an explosion of intracellular reactive oxygen species (ROS). In addition, B. altitudins h217 can significantly reduce the activity of peroxidase (POD) in P. digitatum. These results indicated that B. altitudins h217 has great potential in controlling postharvest diseases of citrus, and its VOCs can also provide new ideas for the development of postharvest fumigants for citrus. This study may provide a new biocontrol agent for controlling P. digitatum in citrus and deepen understanding of the biocontrol mechanism of B. altitudins h217.

Global Transcriptome Analysis of the Peach (Prunus persica) in the Interaction System of Fruit-Chitosan-Monilinia fructicola.

The peach (Prunus persica L.) is one of the most important stone-fruit crops worldwide. Nevertheless, successful peach fruit production is seriously reduced by losses due to Monilinia fructicola the causal agent of brown rot. Chitosan has a broad spectrum of antimicrobial properties and may also act as an elicitor that activate defense responses in plants. As little is known about the elicitation potential of chitosan in peach fruits and its impact at their transcriptional-level profiles, the aim of this study was to uncover using RNA-seq the induced responses regulated by the action of chitosan in fruit-chitosan-M. fructicola interaction. Samples were obtained from fruits treated with chitosan or inoculated with M. fructicola, as well from fruits pre-treated with chitosan and thereafter inoculated with the fungus. Chitosan was found to delay the postharvest decay of fruits, and expression profiles showed that its defense-priming effects were mainly evident after the pathogen challenge, driven particularly by modulations of differentially expressed genes (DEGs) related to cell-wall modifications, pathogen perception, and signal transduction, preventing the spread of fungus. In contrast, as the compatible interaction of fruits with M. fructicola was challenged, a shift towards defense responses was triggered with a delay, which was insufficient to limit fungal expansion, whereas DEGs involved in particular processes have facilitated early pathogen colonization. Physiological indicators of peach fruits were also measured. Additionally, expression profiles of particular M. fructicola genes highlight the direct antimicrobial activity of chitosan against the fungus. Overall, the results clarify the possible mechanisms of chitosan-mediated tolerance to M. fructicola and set new foundations for the potential employment of chitosan in the control of brown rot in peaches.

Exogenous melatonin orchestrates multiple defense responses against Botrytis cinerea in tomato leaves

Infection of tomato leaves and fruits by necrotrophic fungal pathogen Botrytis cinerea causes considerable economic loss. Melatonin has multiple physiological functions and is considered a potential biocontrol agent for its positive effects on plant innate immunity. In tomato, melatonin reduces Botrytis-caused post-harvest fruit decay by activating jasmonic acid (JA) signaling. In this study, we analyzed the effects of melatonin on resistance to Botrytis and associated defense mechanisms in tomato leaves. Treatment of detached tomato leaves with melatonin at a concentration as low as 100 µM induced resistance to Botrytis based on reduced lesion size and fungal growth. Melatonin-induced resistance to gray mold was associated with activation of a complex set of defense mechanisms in tomato leaves. First, melatonin suppressed Botrytis-induced cell death and accumulation of reactive oxygen species (ROS), which was correlated with increased activities of ROS-scavenging enzymes and enhanced expression of their corresponding genes. Second, melatonin treatment induced callose synthase genes and promoted rapid and strong callose deposition in tomato leaves. Melatonin also induced other anti-microbial genes encoding chitinases, β-1,3-glucanases, phenylalanine ammonialyases and polyphenol oxidases. Third, melatonin increased Botrytis-induced expression of genes encoding SlWRKY33, SlMYC2 and SlERF transcription factors, which activate defense-related genes expression through JA and ethylene (ET) signaling pathways. By contrast, melatonin suppressed salicylic acid (SA) signaling based on reduced expression of the SlPR1 marker gene, which is known to antagonize defense against Botrytis. These results collectively indicate that exogenous melatonin orchestrates multiple signaling pathways to activate a complex set of defense mechanisms against Botrytis in tomato leaves.

Effects of methionine treatment on storage quality and antioxidant activity of postharvest jujube fruit

Jujube fruits usually suffer from physiological disorders or infectious diseases during storage, leading to quality deterioration, softening, or rotting. Therefore, this study aims to investigate the effect of methionine soaking treatment on the postharvest jujube fruit decay rate and storage quality. Methionine treatment significantly reduced the decay rate of postharvest jujube fruit and effectively maintained fruit color and titratable acid. Methionine treatment effectively delayed the decrease of firmness, soluble solids, ascorbic acid, and lignin contents in jujube fruit. Methionine treatment reduced the content of alanine and phenylalanine, and increased the content of glycine in jujube fruit, but displayed no significant effect on total amino acid content. In addition, jujube fruits in the methionine treatment group had a higher total phenolic and flavonoid content and antioxidant capacity, both in free and bound forms. Compared with the control, methionine treatment also significantly increased the content of individual phenolic acid fractions (gallic acid, vanillic acid, and syringic acid) and flavonoid fractions (catechin, epicatechin, rutin) in free form as well as individual phenolic acid fractions in bound form (gallic acid and ferulic acid) in jujube fruits. Overall, this study suggested that the methionine treatment could be used as a prospective preservative to reduce the postharvest decay of jujube fruit and alleviate its nutritional quality deterioration during cold storage at 4°C.

Effects of ozone treatment on postharvest decay of peach fruits in cold storage

Effects of ozone treatment on postharvest decay of peach fruits in cold storage

Preharvest application with calcium and maturity at harvest affects postharvest fungal fruit decay of European plum

The combination of preharvest treatments with calcium chloride and fungicides, and storage of maturity graded fruit were assessed in five European plum cultivars. At harvest, samples of fruit within a commercially suitable range in ripening were divided into two categories: less-ripe (tree ripe-) and more-ripe (tree ripe+). The fruit were stored for 10–14 days at 4 °C followed by 2–3 days at 20 °C before the assessment of fungal decay. If calcium chloride was applied six times each season, postharvest fruit decay was significantly reduced in four of nine experiments, with a total mean reduction of around 50%. Two calcium applications in combination with a fungicide treatment reduced decay by approx. 60% compared to the untreated in one experiment. In six of seven experiments there was no effect of preharvest fungicide applications. In six of 10 experiments, fruit of the category tree ripe- had fewer fruit with fungal decay after storage than the tree ripe+fruit. The higher incidence in the category tree ripe+fruit was primarily due to brown rot, Mucor rot, and blue mould. For the category tree ripe+, there was two to ten times more decay than on tree ripe- fruit after a simulated shelf-life period. To ensure low incidence of fungal decay, fruit of commercial harvest maturity may thus be separated in two ripening categories, one for rapid distribution to the market (tree ripe+) and another for extended distribution time (tree ripe-).

Rapid and simple colorimetric detection of quiescent Colletotrichum in harvested fruit using reverse transcriptional loop-mediated isothermal amplification (RT-LAMP) technology

Anthracnose, caused by the fungus Colletotrichum gloeosporioides, is one of the major causes of postharvest decay of fruits and vegetables. Detection of the pathogen at an early stage of infection is crucial to developing a disease management strategy. In this work, a loop-mediated isothermal amplification (LAMP) assay was developed for the rapid detection of C. gloeosporioides targeting the transcript enoyl-CoA hydratase (ECH) that significantly upregulates only during C. gloeosporioides quiescent stage. The assay enabled a naked-eye detection of C. gloeosporioides RNA within 23 min based on a color change of LAMP products from pink to yellow. The detection limit of the LAMP assay was 1 pg of total RNA extracted from fruit peel in a 25 μL reaction. Positive results were obtained only in samples carrying the ECH gene, whereas no cross-reaction was observed for a different quiescent marker (histone deacetylase (HDAC)) or an appressorium marker (scytalone dehydratase, (SD)), indicating the high specificity of the method. Hence, the results indicate that the developed LAMP assay is a rapid, highly sensitive, and specific tool for the early detection of quiescent C. gloeosporioides and could be employed to manage postharvest diseases.

Detection and bio control measures of anthracnose causing fungus isolated from Citrus limon (L.)

Anthracnose is one of the most devastating fungi causing twig dieback and postharvest fruit decay. Present study was aimed to identification of anthracnose fungus. Infected leaves of Citrus limon were collected and cultured on potato dextrose agar (PDA) media for pathogenic fungus isolation. The isolated fungal pure culture was characterized by physiological and morphological characterization methods. Biological control measures of the fungus were evaluated by disc diffusion methods. The highest growth and development of isolated fungus was detected in PDA media pH 7 in fructose as the best carbon source and 0.05gm NaCl concentrations at 37°C. Pathogenicity potency of isolate was performed on lemon, orange and malta, belonging to the Citrus sp. For antifungal activity, 200µgm/disc methanolic extract of Psidium guajava showed 14.33±0.66 mm inhibition zone against the isolated fungus. From the present investigations, identified anthracnose causing fungus and it’s controlling techniques may help for further research for the isolation of drugs related compound for controlling this disease.

Analysis of metabolic and transcription levels provides insights into the interactions of plant hormones and crosstalk with MAPKs in the early signaling response of cherry tomato fruit induced by the yeast cell wall

Yeast cell walls (YCW) are promising bio-based elicitors for controlling post-harvest fruit decay. In this study, 1% YCW induction increased the resistance of cherry tomato fruits, reducing disease incidence by 66%. This study aimed to explore the interaction of hormones and crosstalk with MAPKs (mitogen-activated protein kinases) in the early response of resistance regulation in cherry tomato fruits treated with YCW and U0126. We analyzed the temporal changes in hormone content, the expression of critical genes involved in phytohormone biosynthesis, and signal transduction in cherry tomato fruits response to the induction. Results revealed that jasmonic acid (JA) and brassinosteroids (BR) significantly regulated early resistance response in fruit induced by 1% YCW. The salicylic acid (SA) pathway is inhibited by the activation of the JA pathway. JA and SA signaling pathway crosstalk with the MAPK3 pathway. BR plays an essential role in the regulation of fruit resistance. The BR pathway may function independently when JA/SA and MAPK3 pathways are inhibited.

Fabrication of bio-based hierarchically structured ethylene scavenger films via electrospraying for fruit preservation

One-third of the global food production goes to waste, and fruits and vegetables constitute the majority of this proportion. The phytohormone ethylene is the main cause of postharvest decay of fruits and vegetables, and thus, the effective regulation of ethylene is crucial to address the global challenge of postharvest food waste. Conventional methods, such as the use of metal-based scavengers, chemical additives, and nondegradable coatings, exhibit significant health and environmental issues. Thus, in this study, we fabricated bio-based ethylene scavenger films composed of paper towel (PT) microfibers coated with zein- Artemisia sphaerocephala Krasch . gum (ASKG) nanoparticles (NPs) with core-shell structures via electrospraying. After 15 days of incubation, bananas in the presence of these films exhibited a lower browning rate, higher hardness, and longer shelf life than the banana without an ethylene scavenger film. The hierarchical structure of the films endowed them with several chemical and physical characteristics advantageous to their application as ethylene scavenger films in fruit preservation. While the presence of numerous active functional groups of zein and the high specific surface area of the NPs enhanced the ethylene removal efficiency of the films, the favorable porosity, hydrophobicity, and mechanical properties of the films enhanced their longevity. Thus, the zein-ASKG NPs@PT films fabricated in this study provide an efficient, safe, and sustainable strategy for fruit preservation. One-third of the global food production goes to waste, and fruits and vegetables constitute the majority of this proportion. The phytohormone ethylene is the main cause of postharvest decay of fruits and vegetables. Thus, the development of a highly efficient, safe, and sustainable ethylene scavenger that does not affect the physicochemical and physiological characteristics of the fruit is significant in alleviating fruit waste. • Core-shell zein-ASKG NPs were coated onto a paper towel film via electrospraying. • The film exhibited favorable porosity, mechanical, and hydrophobic properties. • The film exhibited a high ethylene removal efficiency of 8.84 mg/m 3 /h. • The film effectively preserved the quality of bananas and extended their shelf lives.

Autophagy is involved in methyl jasmonate-mediated resistance against Botrytis cinerea in postharvest tomato fruit by regulating jasmonate signaling and reactive oxygen species homeostasis

Postharvest fruit decay is one of the most important limitations for the fruit industry, which results in tremendous economic losses. Methyl jasmonate (MeJA), a critical hormone that participates in postharvest fruit disease control, could activate the autophagy pathway in plants, which plays an important role in stress response. To reveal the role of autophagy in MeJA-induced postharvest fruit resistance against Botrytis cinerea, green-mature tomato fruit was treated with 0.05 mmol L−1 MeJA for 12 h after immersing 50 mmol L−1 lithium chloride (LiCl, an activator of autophagy) or 5 mmol L−1 hydroxychloroquine (HCQ, an inhibitor of autophagy), respectively, for 10 min and stored at 25 ± 1 °C for 12 d The results indicated that MeJA treatment induced transcript levels of autophagy-related genes (SlATGs), promoted autophagosome formation, as well as inhibited disease incidence and lesion diameter of postharvest tomato by activating the transcript levels of genes related jasmonic acid (JA) signaling pathway (SlLOX, SlAOC, SlMYC2, and SlCOI1) and regulating reactive oxygen species (ROS) metabolism, including the increased activities of superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase, and dehydroascorbate reductase and the decreased contents of superoxide anion radical and hydrogen peroxide. However, the above impacts regulated by MeJA were weakened by HCQ pretreatment and boosted by LiCl pretreatment. Moreover, correlation analysis suggested that disease development was negatively correlated with the transcript levels of genes related to autophagy and JA signaling pathway, especially SlATG13a, SlATG18a, and SlMYC2. The principal component analysis also showed that autophagy was involved in MeJA-induced postharvest fruit quality regulation. Overall, these findings indicated that MeJA treatment enhanced postharvest fruit disease resistance, at least in part, via the JA and autophagy pathway.

Fruit bagging reduces the postharvest decay and alters the diversity of fruit surface fungal community in ‘Yali’ pear

BackgroundFruit bagging is an effective technique for fruit protection in the orchard management. Bagging can create a micro-environment for fruit growth and affect fruit quality during storage, in which the diversity of microorganisms may play an important role. Therefore, various methods including biochemistry, analytical chemistry, and bioinformatics methods were used to reveal the influences of fruit bagging on postharvest fruit quality, physiological characters, decay and surface fungal community of ‘Yali’ pear fruit were investigated in this study.ResultsFruit bagging significantly decreased the postharvest decay after 15 days of ambient storage. There were no significant differences in fruit firmness, titratable acid and ethylene production rate between the fruit-bagging and non-bagging group after 15 days of storage, while the soluble solids contents (SSC) and respiration rate in non-bagging fruit was significantly higher than that in fruit-bagging after 15 days of storage. Furthermore, the surface microbes of pear were collected and determined by the new generation sequencing technology. The alpha diversity of fungi in non-bagging fruit decreased significantly after 15 days of storage, while there were no significant changes in bagging fruit. Ascomycota and Basidiomycota were the two major phyla detected in the bagging fruit, and the dominant fungal genera were Alternaria (23.7%), Mycosphaerella (17.25%), Vishniacozyma (16.14%), and Aureobasidium (10.51%) after 15 days of storage. For the non-bagging pear, Ascomycota was the only phylum detected, and the dominant genera was Pichia (83.32%) after 15 days of storage. The abundance of Pichia may be regarded as the biomarker to indicate the degree of fruit decay.ConclusionsThis study showed that fruit bagging could significantly reduce postharvest fruit decay and respiration rate of ‘Yali’ pear. Significant differences were found in fungal composition between bagging and non-bagging pear after storage for 0 or 15 days. Fruit bagging maintained the diversity of fungi on the fruit surface, increased the abundance of non-pathogenic fungi, and even antagonistic fungi such as Aureobasidium, Vishniacozyma, and Mycosphaerella. A reduction in the abundance of pathogenic fungi and incidence of postharvest decay during the storage of ‘Yali’ pear were also recorded. In conclusion, fruit-bagging changed the fungal diversity on fruit surface of ‘Yali’ pear, which had significant effect on reducing postharvest fruit decay, and thus prolong the storage period of ‘Yali’ pears. The future thrust of this study will focus on the isolation of fungi or bacteria from pear fruit surface and identify their roles in causing fruit decay and changing fruit quality during storage.

Biofilm: New insights in the biological control of fruits with Bacillus amyloliquefaciens B4

Biofilms are sessile microbial communities growing on surfaces, which are encased in some self-produced extracellular material. Beneficial biofilm could be widely used in agriculture, food, medicine, environment and other fields. As an ideal biocontrol agent, Bacillus amyloliquefaciens B4 can form a strong biofilm under static conditions. In this study, we screened out metal compounds that enhanced or inhibited the biofilm formation ability of B4, established the relationship between the biofilm of B4 strain and its postharvest biocontrol effect, and explored the regulation of metal compounds on the biofilm formation. The results showed 0.5 mmol L−1 ferric chloride could enhance the biofilm formation and strengthen the antifungal effect of B4, indicating that there was a positive relationship between the growth of biofilm and its biocontrol effect. The enhanced biofilm had a certain biocontrol effect on different fruit, including peach, loquat, Kyoho grape and cherry tomato. Furthermore, the expression of degU and tasA was affected by metal ion treatment, which meant the genes might be essential for the biofilm formation of B4. Our findings suggested that biofilm of B. amyloliquefaciens played an essential role in the process of biocontrol and it might be a novel strategy for managing postharvest fruit decay.

Burkholderia cenocepacia ETR-B22 volatile organic compounds suppress postharvest grey mould infection and maintain aroma quality of tomato fruit

Microbial volatile organic compounds (VOCs) are effective biofumigants for controlling postharvest fruit decay. We evaluated the postharvest biofumigation efficacy of the VOCs produced by Burkholderia cenocepacia ETR-B22 for alleviating tomato fruit grey mould and its impact on the fruit quality. The results demonstrated that the VOCs inhibited the hyphal growth and spore germination of pathogen Botrytis cinerea and caused hyphal cell death. Postharvest biofumigation with VOCs significantly decreased disease incidence, disease index, and weight loss of tomato fruit. The antifungal efficacy of the VOCs was affected by growth media substrates, inoculation volume, and concentration. Among the analysed VOC components, dimethyl trisulfide was most effective in inhibiting B. cinerea. Biofumigation with VOCs produced by ETR-B22 delayed the deterioration of the nutrition quality of tomato fruit. Metabolomics analysis revealed that the aromatic metabolite profile of postharvest tomato fruit was well-maintained after fumigation with ETR-B22 VOCs. Therefore, B. cenocepacia ETR-B22 VOCs could be used as useful biofumigants for extending postharvest tomato fruit shelf life and controlling grey mould disease.

More than a Virulence Factor: Patulin Is a Non-Host-Specific Toxin that Inhibits Postharvest Phytopathogens and Requires Efflux for Penicillium Tolerance.

Mycotoxin contamination is a leading cause of food spoilage and waste on a global scale. Patulin, a mycotoxin produced by Penicillium spp. during postharvest pome fruit decay, causes acute and chronic effects in humans, withstands pasteurization, and is not eliminated by fermentation. While much is known about the impact of patulin on human health, there are significant knowledge gaps concerning the effect of patulin during postharvest fruit-pathogen interactions. Application of patulin on six apple cultivars reproduced some blue mold symptoms that were cultivar-independent and dose-dependent. Identical symptoms were also observed in pear and mandarin orange. Six Penicillium isolates exposed to exogenous patulin exhibited delayed germination after 24 h, yetall produced viable colonies in 7 days. However, four common postharvest phytopathogenic fungi were completely inhibited by patulin during conidial germination and growth, suggesting the toxin is important for Penicillium to dominate the postharvest niche. Using clorgyline, a broad-spectrum efflux pump inhibitor, we demonstrated that efflux plays a role in Penicillium auto-resistance to patulin during conidial germination. The work presented here contributes new knowledge of patulin auto-resistance, its mode of action, and inhibitory role in fungal-fungal interactions. Our findings provide a solid foundation to develop toxin and decay mitigation approaches.

Diversity of Botryosphaeriaceae and Diaporthe Species Associated withPostharvest Apple Fruit Decay in Serbia.

Family Botryosphaeriaceae and the genus Diaporthe (family Diaporthaceae) represent diverse groups of plant pathogens, which include causal agents of leaf spot, shoot blight, branch and stem cankers, dieback, and pre- and postharvest apple fruit decay. Apple fruit with symptoms of light to dark brown decay were collected during and after harvest from 2016 to 2018. Thirty selected isolates, on which pathogenicity was confirmed, were identified and characterized based on multilocus phylogeny and morphology. Five species from the family Botryosphaeriaceae and two from the genus Diaporthe (fam. Diaporthaceae) were discovered. The most commonly isolated was Diplodia seriata followed by Botryosphaeria dothidea. In this work, Diaporthe rudis is described as a new postharvest pathogen of apple fruit. Diplodia bulgarica, Diplodia sapinea, Neofusicoccum yunnanense, and Diaporthe eres are initially described as postharvest apple and D. sapinea as postharvest quince and medlar fruit pathogens in Serbia. Because species of the family Botryosphaeriaceae and the genus Diaporthe are known to cause other diseases on their hosts, have an endophytic nature, and have a wide host range, findings from this study imply that they may become a new challenge for successful fruit production.

Nano- and micro-sized carnauba wax emulsions-based coatings incorporated with ginger essential oil and hydroxypropyl methylcellulose on papaya: Preservation of quality and delay of post-harvest fruit decay.

Carnauba wax nano and micro-sized emulsions and hydroxypropyl methylcellulose coatings, alone or combined with ginger essential oils (GEO) were applied on papayas and evaluated under several storage conditions. In a first experiment, storage parameters were: 6days at 22°C, and 9days at 13°C followed by 5days at 22°C. In a second experiment, storage was: 5days at 22°C, and 10days at 16°C followed by 3days at 22°C. Coating effects were dependent on storage conditions. While fruits were in cold storage, there were few changes; however, at 22°C, the differences between coatings became more evident. Nanoemulsions maintained papaya quality during storage by retarding firmness loss, color changes, and reducing respiration rates, resulting in delayed ripening. GEO exhibited some positive effect on fungal disease control. Nanoemulsion-based coatings improved shelf life by reducing weight loss, color development, and slowing ripening of papaya fruit.