The Antifungal Protein AfpB Induces Regulated Cell Death in Its Parental Fungus <italic toggle="yes">Penicillium digitatum</italic>
ABSTRACT Filamentous fungi produce small cysteine-rich proteins with potent, specific antifungal activity, offering the potential to fight fungal infections that severely threaten human health and food safety and security. The genome of the citrus postharvest fungal pathogen Penicillium digitatum en...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2020-08-01
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| Series: | mSphere |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mSphere.00595-20 |
| _version_ | 1818856770864414720 |
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| author | Adrià Bugeda Sandra Garrigues Mónica Gandía Paloma Manzanares Jose F. Marcos María Coca |
| author_facet | Adrià Bugeda Sandra Garrigues Mónica Gandía Paloma Manzanares Jose F. Marcos María Coca |
| author_sort | Adrià Bugeda |
| collection | DOAJ |
| description | ABSTRACT Filamentous fungi produce small cysteine-rich proteins with potent, specific antifungal activity, offering the potential to fight fungal infections that severely threaten human health and food safety and security. The genome of the citrus postharvest fungal pathogen Penicillium digitatum encodes one of these antifungal proteins, namely AfpB. Biotechnologically produced AfpB inhibited the growth of major pathogenic fungi at minimal concentrations, surprisingly including its parental fungus, and conferred protection to crop plants against fungal infections. This study reports an in-depth characterization of the AfpB mechanism of action, showing that it is a cell-penetrating protein that triggers a regulated cell death program in the target fungus. We prove the importance of AfpB interaction with the fungal cell wall to exert its killing activity, for which protein mannosylation is required. We also show that the potent activity of AfpB correlates with its rapid and efficient uptake by fungal cells through an energy-dependent process. Once internalized, AfpB induces a transcriptional reprogramming signaled by reactive oxygen species that ends in cell death. Our data show that AfpB activates a self-injury program, suggesting that this protein has a biological function in the parental fungus beyond defense against competitors, presumably more related to regulation of the fungal population. Our results demonstrate that this protein is a potent antifungal that acts through various targets to kill fungal cells through a regulated process, making AfpB a promising compound for the development of novel biofungicides with multiple fields of application in crop and postharvest protection, food preservation, and medical therapies. IMPORTANCE Disease-causing fungi pose a serious threat to human health and food safety and security. The limited number of licensed antifungals, together with the emergence of pathogenic fungi with multiple resistance to available antifungals, represents a serious challenge for medicine and agriculture. Therefore, there is an urgent need for new compounds with high fungal specificity and novel antifungal mechanisms. Antifungal proteins in general, and AfpB from Penicillium digitatum in particular, are promising molecules for the development of novel antifungals. This study on AfpB’s mode of action demonstrates its potent, specific fungicidal activity through the interaction with multiple targets, presumably reducing the risk of evolving fungal resistance, and through a regulated cell death process, uncovering this protein as an excellent candidate for a novel biofungicide. The in-depth knowledge on AfpB mechanistic function presented in this work is important to guide its possible future clinical and agricultural applications. |
| first_indexed | 2024-12-19T08:29:47Z |
| format | Article |
| id | doaj.art-975e4a4f6fb64c1aa860102388a50fd4 |
| institution | Directory Open Access Journal |
| issn | 2379-5042 |
| language | English |
| last_indexed | 2024-12-19T08:29:47Z |
| publishDate | 2020-08-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mSphere |
| spelling | doaj.art-975e4a4f6fb64c1aa860102388a50fd42022-12-21T20:29:13ZengAmerican Society for MicrobiologymSphere2379-50422020-08-015410.1128/mSphere.00595-20The Antifungal Protein AfpB Induces Regulated Cell Death in Its Parental Fungus <italic toggle="yes">Penicillium digitatum</italic>Adrià Bugeda0Sandra Garrigues1Mónica Gandía2Paloma Manzanares3Jose F. Marcos4María Coca5Centre for Research in Agricultural Genomics (CRAG, CSIC-IRTA-UAB-UB), Barcelona, SpainInstituto de Agroquímica y Tecnología de Alimentos (IATA, CSIC), Valencia, SpainInstituto de Agroquímica y Tecnología de Alimentos (IATA, CSIC), Valencia, SpainInstituto de Agroquímica y Tecnología de Alimentos (IATA, CSIC), Valencia, SpainInstituto de Agroquímica y Tecnología de Alimentos (IATA, CSIC), Valencia, SpainCentre for Research in Agricultural Genomics (CRAG, CSIC-IRTA-UAB-UB), Barcelona, SpainABSTRACT Filamentous fungi produce small cysteine-rich proteins with potent, specific antifungal activity, offering the potential to fight fungal infections that severely threaten human health and food safety and security. The genome of the citrus postharvest fungal pathogen Penicillium digitatum encodes one of these antifungal proteins, namely AfpB. Biotechnologically produced AfpB inhibited the growth of major pathogenic fungi at minimal concentrations, surprisingly including its parental fungus, and conferred protection to crop plants against fungal infections. This study reports an in-depth characterization of the AfpB mechanism of action, showing that it is a cell-penetrating protein that triggers a regulated cell death program in the target fungus. We prove the importance of AfpB interaction with the fungal cell wall to exert its killing activity, for which protein mannosylation is required. We also show that the potent activity of AfpB correlates with its rapid and efficient uptake by fungal cells through an energy-dependent process. Once internalized, AfpB induces a transcriptional reprogramming signaled by reactive oxygen species that ends in cell death. Our data show that AfpB activates a self-injury program, suggesting that this protein has a biological function in the parental fungus beyond defense against competitors, presumably more related to regulation of the fungal population. Our results demonstrate that this protein is a potent antifungal that acts through various targets to kill fungal cells through a regulated process, making AfpB a promising compound for the development of novel biofungicides with multiple fields of application in crop and postharvest protection, food preservation, and medical therapies. IMPORTANCE Disease-causing fungi pose a serious threat to human health and food safety and security. The limited number of licensed antifungals, together with the emergence of pathogenic fungi with multiple resistance to available antifungals, represents a serious challenge for medicine and agriculture. Therefore, there is an urgent need for new compounds with high fungal specificity and novel antifungal mechanisms. Antifungal proteins in general, and AfpB from Penicillium digitatum in particular, are promising molecules for the development of novel antifungals. This study on AfpB’s mode of action demonstrates its potent, specific fungicidal activity through the interaction with multiple targets, presumably reducing the risk of evolving fungal resistance, and through a regulated cell death process, uncovering this protein as an excellent candidate for a novel biofungicide. The in-depth knowledge on AfpB mechanistic function presented in this work is important to guide its possible future clinical and agricultural applications.https://journals.asm.org/doi/10.1128/mSphere.00595-20antifungal proteinsAFPphytopathogensPenicillium digitatumregulated cell deathcysteine-rich proteins |
| spellingShingle | Adrià Bugeda Sandra Garrigues Mónica Gandía Paloma Manzanares Jose F. Marcos María Coca The Antifungal Protein AfpB Induces Regulated Cell Death in Its Parental Fungus <italic toggle="yes">Penicillium digitatum</italic> mSphere antifungal proteins AFP phytopathogens Penicillium digitatum regulated cell death cysteine-rich proteins |
| title | The Antifungal Protein AfpB Induces Regulated Cell Death in Its Parental Fungus <italic toggle="yes">Penicillium digitatum</italic> |
| title_full | The Antifungal Protein AfpB Induces Regulated Cell Death in Its Parental Fungus <italic toggle="yes">Penicillium digitatum</italic> |
| title_fullStr | The Antifungal Protein AfpB Induces Regulated Cell Death in Its Parental Fungus <italic toggle="yes">Penicillium digitatum</italic> |
| title_full_unstemmed | The Antifungal Protein AfpB Induces Regulated Cell Death in Its Parental Fungus <italic toggle="yes">Penicillium digitatum</italic> |
| title_short | The Antifungal Protein AfpB Induces Regulated Cell Death in Its Parental Fungus <italic toggle="yes">Penicillium digitatum</italic> |
| title_sort | antifungal protein afpb induces regulated cell death in its parental fungus italic toggle yes penicillium digitatum italic |
| topic | antifungal proteins AFP phytopathogens Penicillium digitatum regulated cell death cysteine-rich proteins |
| url | https://journals.asm.org/doi/10.1128/mSphere.00595-20 |
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