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The necrotrophic fungus Penicillium digitatum (Pd) is responsible for the green mold
disease that occurs during postharvest of citrus and causes enormous economic losses around the
world. Fungicides remain the main method used to control postharvest green mold in citrus fruit
storage despite numerous occurrences of resistance to them. Hence, it is...
Contexts in source publication
Context 1
... since the introduction of site-specific fungicides in the late 1960s, fungicide resistance in plant pathogenic fungi has emerged as a major problem in crop control [14]. Since the 1970s, there has been an improvement in crop protection owing to systemic single-site fungicides that possess both protective and eradicating characteristics, such as methylbenzimidazole carbamates (MBC), sterol biosynthesis inhibitors (DMIs), external quinone inhibitors (QoI), and succinate dehydrogenase inhibitors (SDHI) ( Table 1). ...Context 2
... resistance can evolve differently based on the characteristics of the fungicide (fungicide class) ( Table 1). ...Context 3
... is a single-site fungicide and is therefore considered to have a high potential for resistance development regardless of its high activity against Pd. The Fungicide Resistance Action Committee [92] classified SDHI fungicides as medium to high risk with respect to the development of resistance (Table 1) based primarily on single-site mutations of the gene encoding the enzyme succinate target dehydrogenase. The reported resistance has been limited to generation I carboxin fungicides as well as generation II SDHI boscalid. ...Citations
... Mexico is world's leader in Persian lime production as well as in exportation (Raddatz-Mota et al., 2019). However, citrus are highly susceptible to fungus infection during postharvest stage during handling, storage, and marketing (Sánchez-Torres, 2021). Penicillium italicum is considered as one of the most devastating pathogens of citrus fruit (Palou, 2014). ...
A novel edible coating with marine yeast in chitosan matrix was prepared. The biocompatibility of yeast cell incorporation of developed coatings was evaluated in terms of viability. Furthermore, the application of chitosan-based coatings was investigated in order to evaluate their efficacy to preserve postharvest quality and prevent fungal establishment of Penicillium italicum during storage under refrigeration. Results revealed that commercial chitosan as a matrix is compatible with Debaryomyces hansenii by maintaining 100% viability of the initial inoculum using chitosan at 0.5%. Preventive application of chitosan combined with the antagonistic yeast was more effective for controlling fungus infection than individual treatments of chitosan and yeast, showing an additive effect. Chitosan concentration had an impact on pH, TSS, acidity, and colour values. Further, the addition of yeast improved the barrier properties of coatings. This study demonstrates the potential application of chitosan-based coatings with antagonistic yeast D. hansenii for Persian lime quality maintenance as well as an effective alternative against blue mould disease.
... This necrotrophic fungus infects citrus fruits through injuries during handling, transportation, storage, and marketing [2]. P. digitatum is the most destructive postharvest pathogen on citrus fruits and accounts for approximately 90% of total postharvest losses [9,10]. ...
... Additionally, it also promotes fungicide resistance in fungal pathogens. Therefore, biological control is a promising approach to replacing synthetic fungicides in fruit preservation [10,13]; . From native soil samples, we detected three bacterial strains possessing antifungal activity against both the citrus pathogens C. gloeosporioides and P. digitatum. ...
Destruction of citrus fruits by fungal pathogens during preharvest and postharvest stages can result in severe losses for the citrus industry. Antagonistic microorganisms used as biological agents to control citrus pathogens are considered alternatives to synthetic fungicides. In this study, we aimed to identify fungal pathogens causing dominant diseases on citrus fruits in a specialized citrus cultivation region of Vietnam and inspect soilborne Bacillus isolates with antifungal activity against these pathogens. Two fungal pathogens were characterized as Colletotrichum gloeosporioides and Penicillium digitatum based on morphological characteristics and ribosomal DNA internal transcribed spacer sequence analyses. Reinfection assays of orange fruits confirmed that C. gloeosporioides causes stem-end rot, and P. digitatum triggers green mold disease. By the heterologous expression of the green fluorescent protein (GFP) in C. gloeosporioides using Agrobacterium tumefaciens-mediated transformation, we could observe the fungal infection process of the citrus fruit stem-end rot caused by C. gloeosporioides for the first time. Furthermore, we isolated and selected two soilborne Bacillus strains with strong antagonistic activity for preventing the decay of citrus fruits by these pathogens. Molecular analyses of 16 S rRNA and gyrB genes showed that both isolates belong to B. velezensis. Antifungal assays indicated that bacterial culture suspensions could strongly inhibit C. gloeosporioides and P. digitatum, and shield orange fruits from the invasion of the pathogens. Our work provides a highly effective Bacillus-based preservative solution for combating the fungal pathogens C. gloeosporioides and P. digitatum to protect citrus fruits at the postharvest stages.
... Post-harvest diseases, especially green mold, caused by Penicillium digitatum, result in significant economic losses to post-harvest citrus crops which during storage and marketing around the world [1][2][3]. Currently, the control of citrus postharvest diseases mainly depends on the demethylation inhibitor (DMI) fungicide (such as imazalil and prochloraz), but fungicide resistance in Penicillium digitatum has been observed with the abuse of DMI fungicides [4][5][6]. At the same time, concerns about environmental contamination and human health threats have heightened the need to find preservatives that are environmentally friendly and can achieve the same effect as chemical fungicides [5,7]. ...
In this study, a γ-cyclodextrin-cinnamaldehyde inclusion compound (γ-CDCL) was prepared to control green mold caused by Penicillium digitatum (P. digitatum) in citrus. The results showed that the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of γ-CDCL against the mycelial growth of P. digitatum were 2.0 g L−1 and 4.0 g L−1, respectively. Simultaneously, eight × MFC γ-CDCL could effectively reduce the incidence of green mold in citrus fruit without impairment of the fruit qualities, meanwhile, eight × MFC γ-CDCL was comparable to Prochloraz in controlling fruit under natural storage conditions. The structure of γ-CDCL was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) analyses. Results showed that the successful preparation of γ-CDCL was due to the spatial interaction between H-4,8 of cinnamaldehyde and H-5′ of γ-cyclodextrin. Meanwhile, the cell membrane permeability of P. digitatum was impaired by γ-CDCL through massive accumulation of reactive oxygen species, whereas the cell wall integrity was barely affected. These results indicated that γ-CDCL might inhibit the growth of P. digitatum through a membrane damage mechanism and it is a promising alternative to chemical fungicides in controlling the post-harvest citrus decay.
... Strain and growth media. Aspergillus O, 0.005% Na 4 EDTA, pH 6.5) containing variable nitrogen sources, such as sodium nitrate, ammonium sulphate, and proline (70 mM) were used, which were designated GMM(NO 3 ROS assay. Intracellular ROS was visualised using DCFH-DA and an inverted fluorescence microscope (excitation 488 nm and emission 525 nm) (Axio, Zeiss, Oberkochen, Germany). ...
Fungi are ubiquitously present in our living environment and are responsible for crop and infectious diseases. Developing new antifungal agents is constantly needed for their effective control. Here, we investigated fungal cellular responses to an array of antifungal compounds, including plant- and bacteria-derived antifungal compounds. The pathogenic fungus Aspergillus fumigatus generated reactive oxygen species in its hyphae after exposure to the antifungal compounds thymol, farnesol, citral, nerol, salicylic acid, phenazine-1-carbonic acid, and pyocyanin, as well as under oxidative and high-temperature stress conditions. The production of nitric oxide (NO) was determined using diaminofluorescein-FM diacetate (DAF-FM DA) and occurred in response to antifungal compounds and stress conditions. The application of reactive oxygen species or NO scavengers partly suppressed the inhibitory effects of farnesol on germination. However, NO production was not detected in the hyphae using the Greiss method. An LC/MS analysis also failed to detect DAF-FM-T, a theoretical product derived from DAF-FM DA and NO, in the hyphae after antifungal treatments. Thus, the cellular state after exposure to antifungal agents may be more complex than previously believed, and the role of NO in fungal cells needs to be investigated further.
... Although developed to target insects nAChR, adverse effects on vertebrate cell and in vivo animal models were reported, taken together with the fact that high levels of IMD and of its metabolites have been detected in several food products, such as honey, fruits, and vegetables [25]. IMZ (or enilconazole) is a broad spectrum systemic fungicide that blocks ergosterol biosynthesis by targeting cytochrome P450-dependent sterol 14α-demethylase (Cyp51; EC 1.14.13.70) and blocking the production of C14-demethylation of lanosterol, a precursor of ergosterol, [26]. IMZ is used worldwide to prevent postharvest decay of fruit (bananas, citrus fruit, and others), vegetables, and ornamentals [27]. ...
... Although developed to target insects nAChR, adverse effects on vertebrate cell and in vivo animal models were reported, taken together with the fact that high levels of IMD and of its metabolites have been detected in several food products, such as honey, fruits, and vegetables [25]. IMZ (or enilconazole) is a broad spectrum systemic fungicide that blocks ergosterol biosynthesis by targeting cytochrome P450-dependent sterol 14αdemethylase (Cyp51; EC 1.14.13.70) and blocking the production of C14-demethylation of lanosterol, a precursor of ergosterol, [26]. IMZ is used worldwide to prevent postharvest decay of fruit (bananas, citrus fruit, and others), vegetables, and ornamentals [27]. ...
In this work, three pesticides of different physicochemical properties: glyphosate (GLY, herbicide), imidacloprid (IMD, insecticide), and imazalil (IMZ, fungicide), were selected to assess their cytotoxicity against Caco-2 and HepG2 cells. Cell viability was assessed by the Alamar Blue assay, after 24 and 48 h exposure to different concentrations, and IC50 values were calculated. The mechanisms underlying toxicity, namely cellular reactive oxygen species (ROS), glutathione (GSH) content, lipid peroxidation, loss of mitochondrial membrane potential (MMP), and apoptosis/necrosis induction were assessed by flow cytometry. Cytotoxic profiles were further correlated with the molecular physicochemical parameters of pesticides, namely: water solubility, partition coefficient in an n-octanol/water (Log Pow) system, topological polar surface area (TPSA), the number of hydrogen-bonds (donor/acceptor), and rotatable bonds. In vitro outputs resulted in the following toxicity level: IMZ (Caco-2: IC50 = 253.5 ± 3.37 mM, and HepG2: IC50 = 94 ± 12 mM) > IMD (Caco-2: IC50 > 1 mM and HepG2: IC50 = 624 ± 24 mM) > GLY (IC50 > >1 mM, both cell lines), after 24 h treatment, being toxicity time-dependent (lower IC50 values at 48 h). Toxicity is explained by oxidative stress, as IMZ induced a higher intracellular ROS increase and lipid peroxidation, followed by IMD, while GLY did not change these markers. However, the three pesticides induced loss of MMP in HepG2 cells while in Caco-2 cells only IMZ produced significant MMP loss. Increased ROS and loss of MMP promoted apoptosis in Caco-2 cells subjected to IMZ, and in HepG2 cells exposed to IMD and IMZ, as assessed by Annexin-V/PI. The toxicity profile of pesticides is directly correlated with their Log Pow, as affinity for the lipophilic environment favours interaction with cell membranes governs, and is inversely correlated with their TPSA; however, membrane permeation is favoured by lower TPSA. IMZ presents the best molecular properties for membrane interaction and cell permeation, i.e., higher Log Pow, lower TPSA and lower hydrogen-bond (H-bond) donor/acceptor correlating with its higher toxicity. In conclusion, molecular physicochemical factors such as Log Pow, TPSA, and H-bond are likely to be directly correlated with pesticide-induced toxicity, thus they are key factors to potentially predict the toxicity of other compounds.
... 9 Moreover, several resistant fungal strains were reported during the last decades. 10,11 One of the most common alternative strategies to overcome these limitations is using bacterial biocontrol agents. 12,13 In this regard, Bacillus species have been thoroughly studied for the control of postharvest fungal diseases. ...
The Bacillus amyloliquefaciens group, composed of B. amyloliquefaciens, B. velezensis, B. nakamurai and B. siamensis, has recently emerged as an interesting source of biocontrol agents for the management of pathogenic fungi. In this review, all the reports regarding the ability of these species to control postharvest fungal diseases have been covered for the first time. B. amyloliquefaciens species showed various antifungal mechanisms, including production of antifungal lipopeptides and volatile organic compounds, competition for nutrients, and induction of disease resistance. Most reports discussed their use for the control of fruit diseases. Several strains were studied in combination with additives, improving their inhibitory efficacies. In addition, a few strains have been commercialized. Overall, studies showed that B. amyloliquefaciens species are a suitable environmentally friendly alternative for the control of postharvest diseases. However, there are still crucial knowledge gaps to improve their efficacy and host range.
... In the case of pathogens, the loss of genes that are recognized by the immune system of the host can be highly beneficial (Hartmann & Croll, 2017;Morris et al., 2012;Olson, 1999). In contrast, duplications of genes targeted by fungicides have been shown to confer resistance in several species (Coste et al., 2007;Leroux & Walker, 2013;Ma et al., 2006;Morschhäuser, 2016;Sánchez-Torres, 2021;Sionov et al., 2010;Steenwyk & Rokas, 2018;Zhang et al., 2019). Yet, despite their high adaptive potential, systematic population-wide analyses of adaptive CNVs have been scarce (Mérot et al., 2020). ...
... For example, glucose limitation in Saccharomyces cerevisiae cultures resulted in gene duplications encoding glucose transporters, while sulphate limitation resulted in a gene duplication encoding a high-affinity sulphate transporter (Mishra & Whetstine, 2016). In line with these observations, CNVs of genes targeted by fungicides have been repeatedly associated with resistance (Coste et al., 2007;Leroux & Walker, 2013;Ma et al., 2006;Morschhäuser, 2016;Sánchez-Torres, 2021;Sionov et al., 2010;Steenwyk & Rokas, 2018;Zhang et al., 2019). ...
Microbial pathogens can rapidly adapt to changing environments such as the application of pesticides or host resistance. Copy number variations (CNV) are a major source of adaptive genetic variation for recent adaptation. Here, we analyze how a major fungal pathogen of barley, Rhynchosporium commune, has adapted to the host environment and fungicide applications. We screen the genomes of 125 isolates sampled across a worldwide set of populations and identify a total of 7879 gene duplications and 116 gene deletions. Most gene duplications result from segmental chromosomal duplications. Although CNV are generally under negative selection, we find that genes affected by CNV are enriched in functions related to host exploitation (i.e. effectors and cell wall degrading enzymes). We perform genome‐wide association studies (GWAS) and identify a large segmental duplication of CYP51A that has contributed to the emergence of azole resistance and a duplication encompassing an effector gene affecting virulence. We show that the adaptive CNVs were likely created by recently active transposable element families. Moreover, we find that specific transposable element families are important drivers of recent gene copy‐number variation. Finally, we use a genome‐wide SNP dataset to replicate the GWAS and contrast it with the CNV‐focused analysis. Together, our findings show how extensive segmental duplications create the raw material for recent adaptation in global populations of a fungal pathogen.
... MFS transporters are involved in virulence by regulating the secretion of host-specific toxins or providing protection against plant defence components [32]. Together with ABC transporters, these carriers are the most important efflux pumps involved in fungal protection against fungicides [33,34]. More importantly, they were also reported to increase resistance to fungicides through their ability to transport a wide variety of compounds, such as toxic products [23]. ...
Penicillium digitatum is a widespread pathogen responsible for the postharvest decay of citrus, one of the most economically important crops worldwide. Currently, chemical fungicides are still the main strategy to control the green mould disease caused by the fungus. However, the increasing selection and proliferation of fungicide-resistant strains require more efforts to explore new alternatives acting via new or unexplored mechanisms for postharvest disease management. To date, several non-chemical compounds have been investigated for the control of fungal pathogens. In this scenario, understanding the molecular determinants underlying P. digitatum’s response to biological and chemical antifungals may help in the development of safer and more effective non-chemical control methods. In this work, a proteomic approach based on isobaric labelling and a nanoLC tandem mass spectrometry approach was used to investigate molecular changes associated with P. digitatum’s response to treatments with α-sarcin and beetin 27 (BE27), two proteins endowed with antifungal activity. The outcomes of treatments with these biological agents were then compared with those triggered by the commonly used chemical fungicide thiabendazole (TBZ). Our results showed that differentially expressed proteins mainly include cell wall-degrading enzymes, proteins involved in stress response, antioxidant and detoxification mechanisms and metabolic processes such as thiamine biosynthesis. Interestingly, specific modulations in response to protein toxins treatments were observed for a subset of proteins. Deciphering the inhibitory mechanisms of biofungicides and chemical compounds, together with understanding their effects on the fungal physiology, will provide a new direction for improving the efficacy of novel antifungal formulations and developing new control strategies.
Eukaryotic histone deacetylases (HDACs) play a significant role in the different cellular processes since they can regulate chromatin structure and transcription by removing acetyl groups from acetylated lysine residues in the tail of core histones. In fungal plant pathogens, the importance of these enzymes has only begun to notice in recent years, yet there is a dearth of data on them. HDAC gene identification is substantial for understanding the function of the signaling pathways through deacetylation. Therefore, the current study was done to identify the HDAC gene in Fusarium graminearum, a causal agent of Fusarium Head Blight (FHB) in wheat that produces deoxynivalenol (DON) and Nivalenol (NIV) mycotoxins. Fifteen isolates were grown on potato dextrose agar (PDA) and recognized as F. graminearum using molecular markers. Then, HDAC primers, designed by software programs, were used to conduct PCRs to amplify the HDAC gene. The amplification of a 347 bp fragment in all isolates indicated that these primers are acting in a specific manner. Overall, our results may be employed to study post-translational histone modifications in
F. graminearum to offer new strategies for tackling fungal infections.
