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Sugars and organic acids are important factors associated with the postharvest quality of fruits and vegetables, but respiratory metabolism effects the metabolite contents. The objectives of this study were to explore the affects of Fusarium proliferatum infection on the postharvest quality and respiratory metabolism of green asparagus. It was found that F. proliferatum caused the soluble sugar concentration of asparagus to increase over the first 2 d of storage and then decrease again to become significantly lower than the control at 4 d. The titratable acidity (TA) of infected asparagus also increased from day 2 to day 6 and then decreased to become significantly lower than the control. Similarly, the key enzyme activities of the Embden-Meyerhof-Parnas (EMP) pathway, tricarboxylic acid (TCA) cycle, and pentose phosphate pathway (PPP) increased in pathogen-infected asparagus at the beginning of storage and then decreased to become lower than the control at the end. These findings demonstrate that F. proliferatum caused quality deterioration and an impairment of respiratory metabolism in postharvest asparagus. This research helps to clarify the relationships between pathogen infection, physiological metabolism, and asparagus quality and will provide valuable information for the control of postharvest diseases of asparagus.

Blue mold decay is the one of most important postharvest disease of apples caused by the fungus, Penicillium expansum. This study aimed to investigate the biocontrol efficacy of the yeast, Wickerhamomyces anomalus, on postharvest blue mold decay of apples and the relative defense mechanisms. The results indicated that W. anomalus could significantly reduce the blue mold decay of apples, and the maximum inhibition was obtained when the concentration of W. anomalus was 1 × 108 cells ml−1. Furthermore, W. anomalus significantly reduced the fruit decay under ambient conditions, without generating any change in fruit quality. In vitro experiments showed that W. anomalus greatly inhibited the spore germination and germ tube elongation of P. expansum. Besides, its ease of adaptation, stable growth and potential colonization of in apple wounds or surfaces indicated that W. anomalus could compete with P. expansum for nutrients and space, leading to considerable inhibition blue mold decay. W. anomalus significantly induced the activities of polyphenol oxidase (PPO), peroxidase (POD), catalase (CAT), phenylalanine ammonia-lyase (PAL), and ascorbate peroxidase (APX) in apples. Moreover, W. anomalus increased the contents of flavonoid and total phenols. All these results suggested that W. anomalus has potential biocontrol efficacy to control the postharvest blue mold decay of apples

Anarchic growth of ochratoxin A (OTA) producing fungi during crop production, prolonged storage, and processing results in OTA contamination in foodstuffs. OTA in food exacerbates the risk of health and economic problems for consumers and farmers worldwide. Although the toxic effects of OTA on human health have not been well established, comprehensive preventive and remedial measures will be essential to eliminate OTA from foodstuffs. Strict regulations, controlling OTA at pre- or post-harvest stage, and decontamination of OTA have been adopted to prevent human and animal OTA exposure. Biological control of OTA and bio-decontamination are the most promising strategies due to their safety, specificity and nutritional value. This review addresses the current understanding of OTA biodegradation mechanisms and recent developments in OTA control and bio-decontamination strategies. Additionally, this review analyses the strength and weaknesses of different OTA control methods and the contemporary approaches to enhance the efficiency of biocontrol agents. Overall, this review will support the implementation of new strategies to effectively control OTA in food sectors. Further studies on efficacy-related issues, production issues and cost-effectiveness of OTA biocontrol are to be carried out to improve the knowledge, develop improved delivery technologies and safeguard the durability of OTA biocontrol approaches.

Background: Biological control of fruit postharvest diseases by antagonistic microorganisms has been considered an effective alternative to chemical fungicides. The influence of microbial antagonists on fruit-associated microbiome will provide a new perspective for in-depth study of the antagonistic mechanism. In this study, the biocontrol efficacy of A. pullulans S-2 against postharvest diseases of tomatoes was investigated. Meanwhile, the fungal and bacterial microbiota on tomato surfaces were examined by high-throughput sequencing. Results: A. pullulans S-2 can significantly inhibit the decay rate, maintain fruit firmness and reduce weight loss of tomatoes. In addition, the treatment group can maintain higher titratable acid, ascorbic acid and lycopene than the control group. After using A. pullulans S-2, more dramatic changes were observed in fungal diversity than bacterial in the microbiota. Aureobasidium was significantly enriched in the treatment group, while Cladosporium, Mycosphaerella, Alternaria and Penicillium were deficient compared with the control group. Pantoea, Brevibacterium, Brachybacterium, Serratia, Glutamicibacter and Pseudomonas also had significant differences between the two groups.Conclusions: This study demonstrated that the application of A. pullulans S-2 resulted in alterations in the bacterial and fungal community and that could inhibit pathogens and decrease fruit disease incidence. It provides new insights into the dynamics of the tomato's surface microbiome after microbial antagonist treatment.

Transcriptome analysis (TA) was conducted to characterize the transcriptome changes in postharvest disease-related genes of table grapes following treatment with Pichia anomala induced with chitosan (1% w/v). In the current study, the difference in the gene expression of table grapes after treatment with P. anomala induced with chitosan and that of a control group was compared 72 h post-inoculation. The study revealed that postharvest treatment of table grapes with P. anomala induced with chitosan could up-regulate genes that have a pivotal role in the fruit’s disease defense. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) results also confirmed that GO terms and the KEGG pathways, which have pivotal roles in plant disease resistance, were significantly enriched. The up-regulated genes of the treatment group have a unique function in the fruit’s disease resistance compared to the control group. Generally, most genes in the plant–pathogen interaction pathway, the plant Mitogen-activated protein kinase (MAPK) signaling pathway, the plant hormone signal transduction pathway, the pathway of glutathione metabolism, the pathway of phenylalanine, tyrosine, and tryptophan biosynthesis, and the pathway of flavonoid biosynthesis were all up-regulated. These up-regulations help the fruit to synthesize disease-resistant substances, regulate the reactive oxygen species (ROS), enhance the fruit cell wall, and enrich hormone signal transduction during the pathogen’s attack. This study is useful to overcome the lags in applying transcriptomics technology in postharvest pathology, and will provide insight towards developing other alternative methods to using bio-pesticides to control postharvest diseases of perishables.

Patulin contamination not only is a menace to human health but also causes serious environmental problems worldwide due to the synthetic fungicides that are used to control it. This study focused on investigating the patulin degradation mechanism in Pichia caribbica at the molecular level. According to the results, P. caribbica (2 × 106 cells/mL) was able to degrade patulin from 20 μg/mL to an undetectable level in 72 h. The RNA-seq data showed patulin-induced oxidative stress and responses in P. caribbica. The deletion of PcCRG1 led to a significant decrease in patulin degradation by P. caribbica, whereas the overexpression of PcCRG1 accelerated the degradation of patulin. The study identified that PcCRG1 protein had the ability to degrade patulin in vitro. Overall, we demonstrated that the patulin degradation process in P. caribbica was more than one way; PcCRG1 was an S-adenosylmethionine-dependent methyltransferase and played an important role in the patulin degradation process in P. caribbica.

Table grapes are one of the most common fruits throughout the world. Decay of grapes caused by pathogenic fungal infections results in tremendous economic losses. The aim of this study was to evaluate the effect of Yarrowia lipolytica on the control of postharvest decay of grapes caused by Penicillium rubens and the possible mechanisms involved. The results showed that Y. lipolytica provided significant inhibition of the postharvest decay of grapes by P. rubens compared with the control. When the concentration of Y. lipolytica was 1 × 109 cells/mL, decay incidence and decay diameter of grapes were 12.45% and 6.19 mm, respectively. Y. lipolytica reduced spore germination and germ tube length of P. rubens. Moreover, the results also showed that the activities of defense-related enzymes, including polyphenoloxidase (PPO), peroxidase (POD), catalase (CAT), phenylalanine ammonialyase (PAL), ascorbate peroxidase (APX) and β-1,3 glucanase (GLU),were significantly enhanced in grapes treated with Y. lipolytica. Similarly, the expression levels of these genes were also increased in grape fruits treated with Y. lipolytica. The results suggested that the possible resistance mechanism of Y. lipolytica was to enhance the defense-related enzymes and genes, ultimately reduce postharvest decay caused by P. rubens in grapes. Altogether, the research work confirmed that Y. lipolytica has potential biocontrol efficacy and could be used as a biocontrol agent to prevent the postharvest decay of grape fruits.

Penicillium expansum is the causative fungus of blue mold decay in postharvest pears resulting in substantial economic losses. Investigating P. expansum-pear fruit interactions is necessary to help develop P. expansum control strategies for effective and safe pear production. Investigating the P. expansum gene expression alterations and essential gene functions during the infection process is indispensable. Based on our results, the necrosis-inducing protein (NIP) gene was closely associated with genes related to plant cell wall degrading enzymes (CWDEs) and involved in P. expansum virulence. The NIP has high homology with other already-known fungal NIPs. To evidence the role of NIP in P. expansum virulence, NIP mutant (including knockout (ΔNIP) and complementation mutant (cNIP)) P. expansum were generated. Despite the NIP deletion did not affect the basic morphology and structure of P. expansum, it slowed down the fungal growth and hyphal production, thus reducing P. expansum's sporulation and patulin (PAT) accumulation. Furthermore, the deletion of NIP reduced the pathogenicity of P. expansum in pear. The complementation of NIP (cNIP) restored the growth, conidia production, PAT accumulation, and virulence of ΔNIP to the level of wild-type P. expansum. In addition, PAT can cause decay and aggravate the disease severity of wild-type P. expansum and ΔNIP on pears. Our results confirmed NIP plays a crucial role in P. expansum's growth, hyphal production, and pathogenicity in pears.

BACKGROUND In the process of biological control, the antagonistic yeasts contend with various stresses that negatively influence yeasts' biocontrol efficiency. In the current study, we investigated the effect of trehalose supplementation on the biocontrol efficiency and oxidative stress tolerance of Sporidiobolus pararoseus Y16. RESULTS S. pararoseus Y16, an antagonistic yeast cultured in trehalose supplemented medium, exhibited better biocontrol efficiency against Penicillium expansum and Aspergillus tubingensis in table grapes. Trehalose-treated S. pararoseus Y16 cells showed good proliferation efficiency and oxidative stress tolerance than untreated cells. Increased β-1,3-glucanase, catalase, superoxide dismutase activity, and low protein carbonylation were observed in trehalose-amended S. pararoseus Y16 upon H2 O2 exposure. The RNA sequencing results indicated that trehalose significantly altered the transcriptome of S. pararoseus Y16. The GO, KEGG, and COG annotations revealed that the differentially regulated genes corresponded to the various biological process of the yeast. CONCLUSION Our findings suggested that trehalose use could enhance the biocontrol efficiency and oxidative stress tolerance of S. pararoseus Y16. Trehalose supplementation altered the transcriptome of S. pararoseus Y16, particularly the genes that correspond to amino acid metabolism, nucleotide metabolism, and protein modification. Thereby the oxidative stress tolerance and biological control efficiency of S. pararoseus Y16 was enhanced by trehalose. © 2021 Society of Chemical Industry.

Fruit-based diets have been adopted by the public worldwide because of their nutritional value. Many advances have also been made in the elucidation of host-pathogen interaction in the postharvest phase of fruits, in the hope of improving the management of diseases caused by pathogenic molds. In this study, we presented the molecular mechanisms by which pathogenic mold infects fruit in the postharvest phase, and focused on the knowledge gained from recent molecular techniques such as differential analysis of gene expression, targeted insertion, and mutagenesis. Current postharvest pathogenic fungal control strategies were then examined on the basis of their mechanisms for altering the infection process in order to explore new perspectives for securing fruit production. We found that biotechnological advances have led to an understanding of the new basic molecular processes involved in fruit fungal infection and to the identification of new genes, proteins and key factors that could serve as ideal targets for innovative antifungal strategies. In addition, the most commonly used steps to evaluate an approach to disrupt the fruit fungal infection process are mainly based on the inhibition of mycelial growth, spore germination, disruption of Adenosine triphosphate (ATP) synthesis, induction of oxidative stress, cell wall membrane damage, and inhibition of key enzymes. Finally, the alteration of the molecular mechanisms of signaling and response pathways to infection stimulation should also guide the development of effective control strategies to ensure fruit production., This work was supported by the National Natural Science Foundation of China (32072276, 31901743), Natural Science Foundation of the Jiangsu Higher Education Institutions of China (18KJB550002).

The evaluation of drug delivery potential, molecular interactions of the polymeric nanoparticles with the drug molecule and release kinetics encounters more time consumption and also cost. In this study, we have adopted the combination of in vitro and in silico approaches to evaluate the drug delivery property of the polymeric nanoparticles viz. chitin and chitosan. Herein, two different therapeutic agents such as curcumin (a hydrophobic drug) and insulin (a therapeutic protein) were used to study the delivery potential of chitin and chitosan nanoparticles. The drug loaded chitin and chitosan nanoparticles were prepared and characterized using Fourier transform infra red spectroscopy, X-ray diffraction, dynamic light scattering and scanning electron microscopy analysis. In the in vitro drug delivery experiments, chitosan nanoparticles exhibited better encapsulation efficiency, drug loading capacity and prolonged release of the drug molecules than that of the chitin nanoparticles to both curcumin and insulin. Meanwhile the in silico experiments such as molecular docking and molecular dynamics predicted the molecular interactions and binding energy involved between the nanoparticles and the drug molecules. From this study, we suggest that the chitosan nanoparticles could be used as a carrier molecule for both curcumin and insulin.

It has been reported that Yarrowia lipolytica can effectively control blue mold and green mold decay of mandarins (Citrus reticulata), and also the possible physiological mechanisms underlying this efficacy were studied in our previously research. However, the related molecular mechanisms were not clearly. In this study, the molecular mechanisms of disease-resistance in mandarins induced by Y. lipolytica were investigated. It was found that, after the treatment of Y. lipolytica, the related resistance enzyme activities of β-1,3-glucanase, superoxide dismutase, and ascorbate peroxidase in mandarins were enhanced, while the malondialdehyde content was decreased. Interestingly, based on the transcriptome analysis, it was found that Y. lipolytica can induce the up-regulation of genes related to the synthesis of resistant substances; key genes in the pathway of plant-pathogen interaction; genes related to scavenging reactive oxygen species; genes related to jasmonic acid, salicylic acid and ethylene signal transduction pathway in mandarins. Furthermore, Y. lipolytica down-regulated the expression levels of genes encoding cell wall degrading enzymes. Definitively, this unravelling of the molecular mechanisms of Y. lipolytica will contribute to consolidate its potential to serve as an effective biocontrol agent against post-harvest diseases of mandarins.

Grapes are high nutritional and economic fruit but extremely vulnerable to fungus infections during postharvest storage. Our previous study found that the fungi, Talaromyces rugulosus O1 secretes ochratoxin A (OTA), which inflicts consumer health and economic value. This study found that T. rugulosus O1 has strong pathogenicity and spore germination to produce germ tubes to help it infect grapes. To better understand the molecular interaction between T. rugulosus O1 and grape, RNA sequencing (RNA-seq) was performed, and 5037 genes were identified as differentially expressed genes (DEGs) in grapes after T. rugulosus O1 infection. RNA-seq analysis revealed that T. rugulosus O1 infection, induced complex defense reactions in grapes, including an influx of Ca2+, oxidative burst, changes in GSH, plant hormone signal transduction, transcription factor regulation, overexpression of protein kinases, and biosynthesis of plant secondary metabolites. Our study found that the activity of the resistance enzymes in grapes was increased after T. rugulosus O1 infection, which is consistent with the RNA-seq results. Moreover, the accumulation of some antifungal compounds, including flavonoids, phenols, and lignin in grapes, increased grapes' antifungal ability.

Penicillium expansum is a pathogenic fungus that causes blue mold decay in various fruits and produces toxic substances. This study investigated the effect of alginate oligosaccharide (AOS) combined with Meyerozyma guilliermondii, a biocontrol yeast, to control blue mold decay in pears and the possible physiological biocontrol mechanisms. The results showed that AOS (5 g/L) combined with M. guilliermondii could significantly reduce the blue mold decay incidence and lesion diameter of pears. Moreover, AOS did not affect the growth and reproduction of M. guilliermondii in vitro or in vivo of pears. And could inhibit mycelium development, reduce spore germination rate and inhibit the germ tube elongation of P. expansum. AOS combined with M. guilliermondii increased the activities of superoxide dismutase (SOD), catalase (CAT), polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia-lyase (PAL), chitinase (CHI), total phenol content, and flavonoid content in pears. Overall, our study evidenced that AOS improves the efficacy of M. guilliermondii and could be used to control the blue mold decay in pears.

Gray mold decay caused by Botrytis cinerea is one of the primary postharvest diseases of cherry tomatoes globally, leading to considerable economic losses. This study aimed to assess the biocontrol efficacy of Wickerhamomyces anomalus against postharvest gray mold decay in cherry tomatoes. The results indicated that W. anomalus significantly reduced the gray mold decay in cherry tomatoes in a concentration-dependent manner without affecting cherry tomatoes' quality. W. anomalus developed rapidly in wounds and on surfaces of cherry tomatoes at both 20 ± 2 °C and 4 ± 2 °C, and reduced the spore germination and germ tube length of B. cinerea in vitro. W. anomalus could adapt to the environment and compete for the nutrients and space against the pathogens. Besides, W. anomalus significantly enhanced the activities of defense-related enzymes in cherry tomatoes, including polyphenoloxidase (PPO), peroxidase (POD), catalase (CAT), and phenylalanine ammonialyase (PAL). Ultimately, the application of W. anomalus induced the disease resistance ability of cherry tomatoes. These findings suggested that W. anomalus could be a promising biocontrol agent to manage the postharvest gray mold decay in cherry tomatoes.

Penicillium digitatum is one of the most important pathogens known widely to cause postharvest losses of citrus. It is significant to explore its infection mechanism to improve the control technology of postharvest diseases of citrus. This research aimed to study the changes in gene expression of P. digitatum at its early stages of citrus infection by transcriptomics sequencing and bioinformatics analysis in order to explore the molecular mechanism of its infection. The results showed that genes associated with pathogenic factors, such as cell wall degrading enzymes, ethylene, organic acids, and effectors, were significantly up-regulated. Concurrently, genes related to anti-oxidation and iron transport were equally up-regulated at varying degrees. From this study, we demonstrated a simple blueprint for the infection mechanism of P. digitatum in Citrus reticulata Blanco, which provided a new direction for subsequent pathological research and paves the way for developing new control strategies.

Patulin contamination not only is a menace to human health but also causes serious environmental problems worldwide due to the synthetic fungicides that are used to control it. This study focused on investigating the patulin degradation mechanism in