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β-1,3-glucanase plays an important role in the biodegradation, reconstruction, and development of β-1,3-glucan. An endo-β-1,3-glucanase which was encoded by PeBgl1 was expressed, purified and characterized from Penicillium expansum for the first time. The PeBgl1 gene was amplified and transformed into the competent cells of E. coli Rosetta strain with the help of the pET-30a cloning vector. The recombinant protein PeBgl1 was expressed successfully at the induction conditions of 0.8 mmol/L IPTG at 16 °C for 16 h and then was purified by nickel ion affinity chromatography. The optimum reaction temperature of PeBgl1 was 55 °C and it had maximal activity at pH 6.0 according to the enzymatic analysis. Na2HPO4-NaH2PO4 buffer (pH 6.0) and NaCl have inhibitory and enhancing effects on the enzyme activities, respectively. SDS, TritonX-100 and some metal ions (Mg2+, Ca2+, Ba2+, Cu2+, and Zn2+) have an inhibitory effect on the enzyme activity. The results showed that PeBgl1 protein has good enzyme activity at 50–60 °C and at pH 5.0–9.0, and it is not a metal dependent enzyme, which makes it robust for storage and transportation, ultimately holding great promise in green biotechnology and biorefining. [ABSTRACT FROM AUTHOR]

One of the most significant challenges associated with postharvest apple deterioration is the blue mold caused by Penicillium expansum, which leads to considerable economic losses to apple production industries. Apple fruits are susceptible to mold infection owing to their high nutrient and water content, and current physical control methods can delay but cannot completely inhibit P. expansum growth. Biological control methods present promising alternatives; however, they are not always cost effective and have application restrictions. P. expansum infection not only enhances disease pathogenicity, but also inhibits the expression of host-related defense genes. The implementation of new ways to investigate and control P. expansum are expected with the advent of omics technology. Advances in these techniques, together with molecular biology approaches such as targeted gene deletion and whole genome sequencing, will lead to a better understanding of the P. expansum infectious machinery. Here, we review the progress of research on the blue mold disease caused by P. expansum in apples, including physiological and molecular infection mechanisms, as well as various methods to control this common plant pathogen. [ABSTRACT FROM AUTHOR]

Transcription factors play a key role in Penicillium expansum infection process. Although the crucial characteristics of some transcription factors of pathogenic fungi have been found, many transcription factors involved in P. expansum infections have not been explored and studied. This study aimed to screen the transcription factors of P. expansum involved in postharvest pear infections by ATAC-seq analysis and to analyze the differentially expressed peak-related genes by GO enrichment and KEGG pathway analysis. Our results found the up-regulation of differentially expressed peak-related genes involved in the MAPK signaling pathway, pentose phosphate pathway, starch and sucrose metabolism, and pentose and glucuronate interconversions. Our study especially confirmed the differential regulation of transcription factors MCM1, Ste12 and gene WSC in the MAPK signaling pathway and PG1, RPE1 in the pentose and glucuronate interconversions pathway. These transcription factors and related genes might play an essential role in pear fruit infection by P. expansum. RT-qPCR validation of twelve expressed peak-related genes in P. expansum showed that the expression levels of these twelve genes were compatible with the ATAC-Seq. Our findings might shed some light on the regulatory molecular networks consisting of transcription factors that engaged in P. expansum invasion and infection of pear fruits. [ABSTRACT FROM AUTHOR]

Penicillium expansum is one of the primary pathogens causing postharvest blue mold of pears, which leads to the spoiling of pulp and produces patulin, endangering food security. Mitogen-activated protein kinase (MAPK) signaling pathway regulates the growth and development, cell wall integrity, and pathogenicity of fungi. Mitogen-activated protein kinase kinase (MKK) in the MAPK signaling pathway has been reflected to be associated with fungal cell wall integrity. Nevertheless, the pivotal function of MKK in the process of P. expansum infection remained unexplored. In this study, MKK was knocked out and repaired by the Agrobacterium -mediated homologous recombination technology to explore the function of MKK in P. expansum infection process. It has been found that the deletion of MKK induces morphological changes in the mutant strain and delayed mycelium and spore growth. Further studies showed that the mutant strain was susceptible to cell wall interference compounds and showed a significant decrease in decay diameters and virulence during the infection of the pears. RT-qPCR analysis showed that the deletion of MKK affected the relative expression levels of its upstream and downstream genes. Our results suggest that MKK is essential in the growth and development, cell wall integrity, pathogenicity, and toxigenic capacity of P. expansum. • MAP kinase MKK negatively affects the growth of Penicillium expansum. • The knockout of MKK reduces the ability of P. expansum to infect the pears. • The knockout of MKK diminishes the toxigenic capacity of P. expansum infecting pears. [ABSTRACT FROM AUTHOR]

To study the mechanism by which Pichia anomala induced with chitosan (1% w/v) controls blue mold disease in table grapes caused by Penicillium expansum , this study evaluated alterations in three yeast enzymatic activities. The changes in the five primary disease defense-related enzymes and two non-enzyme activities of table grapes were assayed. The results of the study showed that chitosan (1% w/v) significantly increased the yeast β-1,3-glucanase, catalase (CAT), and malondialdehyde (MDA) activities. Furthermore, P. anomala alone or induced with chitosan (1% w/v) significantly increased the table grapes enzymatic activities of Polyphenol oxidase (PPO), phenylalanine (PAL), peroxidase (POD), and catalase (CAT) compared to the control. The RT-qPCR results also confirmed that the genes of these major disease defense enzymes were up-regulated when the table grapes were treated with P. anomala. The highest results were recorded when the fruit was treated by yeast induced with chitosan (1% w/v). The phenolic compounds, in addition to their nutritional value, can also increase the antimicrobial properties of table grapes. The current experiment determined that the total phenol and flavonoid contents of table grapes showed the highest results for fruits treated by P. anomala induced with chitosan compared with the control. Generally, the increment of these fruit enzymatic and non-enzymatic activities shows improved table grape defense against the pathogenic fungus. The induction of the yeast with chitosan also increases its bio-control efficacy against the pathogen. This study will enable future detailed investigation in the yeast pathogen control mechanisms and the use of yeasts as bio-pesticides. [ABSTRACT FROM AUTHOR]

Blue mold decay caused by Penicillium expansum is a global destructive postharvest disease, which has brought huge economic losses to the pear industry. Transcription factors play an important role in pear anti-infection defense, and it has been observed that they have multiple functions. However, the roles of numerous TFs in the defense of pear against P. expansum have not been adequately explored. In this study, ATAC-seq was used to screen the TFs of pear against P. expansum , thereby understanding the chromatin-mediated gene regulation in the defense of pear against infection. The peak of differential expression enriched 9 transcription factors (AGL27, AT5G02460, AT2G28810, AT5G66940, AT3G46070 and OBP1, TCP3, BPC1 and TCP17). The up-regulated genes in our study were implicated in the MAPK signaling pathway-plant, plant hormone signal transduction pathway, plant-pathogen interaction pathway, glutathione metabolism pathway, phenylpropanoid biosynthesis, flavonoid biosynthesis pathway and carotenoid biosynthesis pathway were identified. Especially the transcription factors TGA, gene SAUR and CYCD3 in plant hormone signal transduction pathway and NCED , CYP707A in carotenoid biosynthesis pathway were differentially regulated. RT-qPCR analysis of twelve randomly selected differentially expressed peak-related genes confirmed the accuracy of ATAC-seq analysis of P. expansum infected pear. • Transcription factors of pear against P. expansum infection were screened by ATAC-seq. • MAPK signaling pathway in pear was activated by P. expansum. • SAUR , CYCD3 and TF TGA in plant hormone signal transduction pathway were up-regulated. • NCED and CYP707A in carotenoid biosynthesis pathway were up-regulated. [ABSTRACT FROM AUTHOR]

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Postharvest disease of pears caused by pathogens results in great economic losses. The aim of this research was to isolate a strain of potential antagonistic yeast from soil of orchards, and to test the control efficacy against postharvest blue mold decay of pears. By molecular biological identification based on comparative sequence analysis of 5.8S rDNA gene, the antagonistic strain was identified as Wickerhamomyces anomalus. The results showed that W. anomalus significantly reduced the disease incidence and lesion diameter of blue mold of pears compared with the control in vivo. The disease incidence caused by Penicillium expansum of pears was only 5.56%, when treated with 1 × 108 cells/mL W. anomalus , compared with 100% disease incidence of the control. In vitro test showed that W. anomalus reduced the spore germination rate and germ tube length of P. expansum. Meanwhile, polyphenoloxidase (PPO), peroxidase (POD), catalase (CAT) and chitinase (CHI) activities of the pears treated by W. anomalus were significantly higher than that of the control. And the expression levels of defense-related enzymes were significantly induced by W. anomalus. All these results indicated that W. anomalus has the potential to control postharvest diseases of pears, and the mechanisms involved in inhibiting spore germination and germ tube length, induction of the activities of the defense-related enzymes of pears, and improvement of the expression levels of defense-related genes of pears. [ABSTRACT FROM AUTHOR]

• M. caribbica had a great biocontrol efficacy against blue mold decay of kiwifruit. • M. caribbica could inhibit the growth of Penicillium expansum in vitro. • M. caribbica induced PPO, POD, APX, SOD and PAL activities of kiwifruit. • M. caribbica increased flavonoids, phenolic and lignin content of kiwifruit. Kiwifruit are susceptible to Penicillium expansum infestation, resulting in decay and causing severe economic losses. In this study, we investigated the efficacy and related mechanism of Meyerozyma caribbica in controlling and preventing of P. expansum. The yeast was found to significantly reduce the disease incidence of blue mold in kiwifruit, inhibit the growth of P. expansum in vitro, and reduce both the spore germination rate and germ tube length in a dose-dependent manner. Meanwhile, M. caribbica can stably growth on kiwifruit at 20℃ and 4℃ and had the ability to form biofilm. In addition, the results of this study also showed that M. caribbica induced an increase in polyphenol oxidase (PPO), peroxidase (POD), ascorbate peroxidase (APX), superoxide dismutase (SOD), and phenylalanine ammonia lyase (PAL) activities of kiwifruit and reduced the content of malondialdehyde (MDA). The content of secondary metabolites such as total phenols, flavonoids, and lignin were also increased after yeast application. These experiments indicate that M. caribbica has a strong adaptation to the environment and relies on competition for nutrients and space against pathogens. The induction of disease resistance in fruits is also one of the important mechanisms to control the occurrence of blue mold in kiwifruit. In summary, M. caribbica has the potential to be an antagonistic yeast for controlling postharvest blue mold of kiwifruit. [ABSTRACT FROM AUTHOR]

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. • M. guilliermondii combined with AOS reduced the blue mold decay of pears. • AOS had no effect on the growth and reproduction of M. guilliermondii. • AOS combined with M. guilliermondii inhibited the growth of P. expansum in vitro. • AOS with M. guilliermondii induced defense-related enzyme activities of pears. [ABSTRACT FROM AUTHOR]

Apple is one of the largely grown fruits in China, and it suffers great economic losses caused by Penicillium expansum infection every year. In the present study, we ascertained the efficacy of Meyerozyma guilliermondii enhanced by 200 μmol/L methyl jasmonate (MeJA) in controlling the postharvest blue mold decay of apples and the possible mechanisms involved. The results demonstrated that the biological control ability of M. guilliermondii induced by MeJA in restraining P. expansum infection in apples. The efficacy of M. guilliermondii induced by MeJA significantly decreased the decay incidence and lesion diameter of apples. When treated with M. guilliermondii induced by MeJA, the decay incidence of apples was only 21.6%, while apples treated with M. guilliermondii was 42.4%. M. guilliermondii induced by MeJA also reduced the germ tube length, spore germination rate of P. expansum in PDB and colony diameter of P. expansum in PDA. The results also showed that antagonistic yeast induced by MeJA proliferated better in apple wounds and surface at 4 °C or 20 °C. Meanwhile, the activities of resistance-related peroxidase (POD), polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), Catalase (CAT), and the antibacterial substances of flavonoid contents, total phenolic content were all increased. The results manifested that M. guilliermondii induced by MeJA increased the expression levels of defense-related enzymes in apples. • M. guilliermondii induced by MeJA decreased blue mold decay of apples. • M. guilliermondii induced by MeJA colonized in apples steadily at 20 °C and 4 °C. • M. guilliermondii induced by MeJA decreased spore germination rate of P. expansum. • M. guilliermondii induced by MeJA increased PPO, POD, CAT, PAL activities of apples. • M. guilliermondii induced by MeJA increased the expression of PPO, POD, PAL, CAT. [ABSTRACT FROM AUTHOR]

Penicillium expansum (P. expansum) is a harmful pathogenic mold responsible for huge postharvest losses in apples. Epsilon‐poly‐L‐lysine (ε-PL) is a non-toxic antiseptic peptide derived from Streptomyces albulus. Many food preservative strategies use ε-PL to suppress foodborne pathogens in condiments, cakes, fruit and vegetable juices. In the present research, ε-PL's inhibitory effects against P. expansum in vitro and in apples were investigated. The molecular mechanisms of ε-PL inhibiting P. expansum in apples were investigated by transcriptome analysis. Results showed that doses of 600 mg L−1 of ε-PL could prevent the development of P. expansum in vitro and control blue mold decay in apples. Plausible mechanisms of ε-PL against P. expansum in apples include: (i) reduction of antioxidant potential, including decreasing the expression of genes encoding superoxide dismutase (SOD), catalase (CAT), glutathione s-transferase (GST), xanthine dehydrogenase (XDH), D -amino-acid oxidase (DAO), weakening ROS scavenging ability of P. expansum cells and causing oxidative damage to cell, (ii) weakening its virulence towards apples, including reducing the expression of genes coding for cell wall degrading enzymes (CWDEs) such as pectinase and cellulase, (iii) disrupting mitochondrial function of P. expansum , including reducing expression of several rate-limiting enzyme coding genes of energy metabolic pathways such as EMP, TCA cycle and oxidative phosphorylation, which interfered with the cells' energy metabolism, leading to insufficient ATP synthesis, weakening P. expansum 's resistance to external stress, and finally slowing down the invasion process into apples, (ⅳ) damaging the membrane integrity of P. expansum , including reducing the expression of genes encoding diaphragm wall degradation enzymes, cytomembrane lipid and ergosterol synthetase, multi-drug transporter, and inhibiting the differentiation of conidia. • 600 mg L−1 of ε-PL can significantly inhibit P. expansum in vitro or in apples. • ε-PL decreased the expression of genes encoding antioxidant enzyme of P. expansum. • ε-PL reduced the expression of genes coding CWDEs, weakened its virulence to apples. • ε-PL interfered the mitochondrial function and energy metabolism of P. expansum. • ε-PL damaged the membrane integrity of P. expansum in apples. [ABSTRACT FROM AUTHOR]

This study assessed the biocontrol efficacy of Meyerozyma guilliermondii against blue mold decay caused by Penicillium expansum in pears and the possible mechanisms involved. The results indicated that M. guilliermondii significantly inhibited the blue mold decay caused by P. expansum without affecting the quality of the pears. M. guilliermondii rapidly colonized the wounds and surfaces of the pears at both 4 °C and 20 °C. The rapid growth in the population of M. guilliermondii in the wounds and surface environments of pears indicated that it has the potential to inhibit pathogens in pears. The activities of antioxidant enzymes (peroxidase and catalase) in the pear were improved after the application of the yeast. Phenylalanine ammonialyase (PAL), a key enzyme involved in lignin biosynthesis and defense related activity, was also markedly enhanced. Generally, the application of yeast induced disease resistance in the pear. The results pear proteomics profile after M. guilliermondii treatment showed that 17 proteins were significantly up-regulated and 13 were down-regulated in response to induction with M. guilliermondii . Most of the proteins were involved in defense and stress responses based on biological process. These results provided a new insight into the biocontrol mechanism of the antagonist yeast in the pear fruit. [ABSTRACT FROM AUTHOR]

Penicillium expansum is an important postharvest pome fruit pathogen causing massive spoilage of stored fruits and high economic losses. The present study aimed to identify an essential gene of P. expansum and to investigate its effect in postharvest apple infection. Cytoscape and RNA-sequencing analysis identified a P. expansum PeBgl1 gene which was a hub gene and also upregulated expression at three key time points (1, 3, and 6 h) during apple infection. The PeBgl1 gene was 798 bp in length, encoded 265 amino acids and had high homology with glycoside hydrolase superfamily of P. expansum. The PeBgl1 gene affected the colony morphology especially the colony color and delayed fungal growth both of P. expansum both in vivo and in vitro. This gene also decreased the pathogenicity of P. expansum in apples. Based on these results, we conclude that PeBgl1 is responsible for growth and pathogenicity in P. expansum. • PeBgl1 is identified as an essential gene of P. expansum during apple infection. • PeBgl1 gene knockout delays P. expansum growth and morphology. • PeBgl1 knocked out decreased the pathogenicity of P. expansum in apple. [ABSTRACT FROM AUTHOR]

Penicillium expansum causes blue mold disease in pears during storage and transportation, causing huge economic losses. However, researches on the defense mechanisms of pears against P. expansum are still in the early stages. Therefore, many unknown disease-resistant factors have yet to be excavated, severely limiting the breakthrough progress of pear blue mold control strategies. The current study used transcriptome and proteome approaches to evaluate pear defense mechanisms following infection with P. expansum. 96% of pear proteins were associated with the transcriptome data. Gene Ontology (GO) enrichment analysis determined that the remaining associated genes/proteins were significantly enriched in 80 GO terms. The significantly enriched GO terms included oxyacid metabolism, aldehyde-lyase activity, transition metal ion binding, terpenoid metabolic process, response to stimulus, etc. An enrichment analysis conducted by the Kyoto Encyclopedia of Genes and Genomes (KEGG) showed that 122 metabolic pathways were enriched, of which 11 were closely related to other metabolic pathways. In these 11 metabolic pathways, the genes/proteins (such as peroxidase, histidinol-phosphate aminotransferase (hisC), prephenate dehydratase (ADT), etc.) related to the biosynthesis of plant secondary metabolites, and the genes/proteins (such as ethylene-responsive transcription factor 1 (ERF), BR-signaling kinase (BSK), brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1), etc.) related to plant hormones were significantly enriched. Overall, this study provides a deep understanding of pear's defense response, which could be used in future research to develop strategies to control fungal diseases. • TMT and RNA-Seq were used on postharvest pear response to P. expansum infection. • Functional annotation of associated DEGs/DEPs were done by GO and KEGG enrichment. • DEGs/DEPs in plant hormone signal transduction showed significant expression. • DEGs/DEPs related to secondary metabolite synthesis showed significant expression. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-level NIP expression was observed during P. expansum infection. • NIP was closely associated with genes related to plant CWDEs. • NIP was functionally characterized by knockout and complementation. • Δ NIP reduces sporulation and PAT accumulation via reduced mycelial production. • NIP contributes to P. expansum virulence. 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 (Δ NIP) and complementation mutant (c NIP)) 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 (c NIP) restored the growth, conidia production, PAT accumulation, and virulence of Δ NIP 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 Δ NIP on pears. Our results confirmed NIP plays a crucial role in P. expansum 's growth, hyphal production, and pathogenicity in pears. [ABSTRACT FROM AUTHOR]

• Pear gene expression response to P. expansum were clustered by STEM analysis. • Functional annotation of DEGs in profiles were done by GO and KEGG enrichment. • Pears can produce a complex defense reactions after P. expansum infection. • P. expansum can increase the activities of resistant enzymes in pears. In pears, blue mold decay caused by Penicillium expansum, is a destructive postharvest disease around the world, which leads to stasis of the pear industry and creates huge economic losses. Our previous research work proved that P. expansum mainly secretes cell wall degrading enzymes (CWDEs) to infect pears. To further understand the molecular basis of P. expansum infection and disease progression, in the present study we have tried to investigate the transcriptome of pears infected with P. expansum. The differentially expressed genes (DEGs) identified from the RNA-seq results were clustered into 2 upward trends and 6 downward trends according to their gene expression patterns. Comparison of Gene ontology (GO) terms in downward and upward trend profiles evidenced that the enriched GO terms (included metabolic processes for l -phenylalanine, aromatic amino acid family and ethylene, etc.), found in upward trend profiles were more relevant to pear defense. Moreover, the Kyoto Encyclopedia of Genes and Genomes (KEGG) results revealed that pears can produce a complex defense response against P. expansum infection. Briefly, P. expansum produced CWDEs to establish infection, which triggers relevant transduction pathways in pear. These pathways led to further activation of the secondary regulatory networks. Finally, some metabolites were synthesised to defense against P. expansum. In general, the information obtained in this study will be supportive to develop new strategies to control fungal diseases. [ABSTRACT FROM AUTHOR]

Blue mold decay caused by Penicillium expansum is one of the recently identified diseases of grapes (Vitis vinifera). The increasing concern about the use of chemical substances and pesticides in postharvest fruit pushes the trends of research toward bio-control strategies which are more sustainable and eco-friendly. This study determined the bio-control efficacy of Pichia anomala alone and supplemented with 1% chitosan in the grapes against blue mold disease. The result showed that chitosan (1%) better induced the bio-control efficacy of P. anomala. P. anomala supplemented with 1% w/v chitosan significantly reduced the disease incidence, lesion diameter and natural decay of grapes without affecting the fruit quality compared to the control. In addition it enhanced the activities of disease defence related enzymes like ascorbate peroxidase (APX) and chitinase (CHI); and decreased the formation of malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2) which are responsible for fruits deterioration. The scanned electron microscope (SEM) concisely illustrates how the high denser yeast cells on the wounds reduced the growth of P. expansum mycelia. So it can be concluded that, P. anomala alone or P. anomala supplemented with 1% w/v chitosan can be presented as a potential bio-control alternative against the postharvest blue mold of grapes. • Pichia anomala is reported to control the blue mold disease of grapes. • Chitosan 1% w/v enhances biocontrol ability of P. anomala. • P. anomala enhanced chitosan rapidly grow in the wounds and surface of grapes. • P. anomala enhanced by chitosan reduced spore germination of P. expansum. • P. anomala cells on the grape wounds reduced the growth of P. expansum. [ABSTRACT FROM AUTHOR]