Mutational Analysis of <i>Aspergillus fumigatus</i> Volatile Oxylipins in a <i>Drosophila</i> Eclosion Assay
<i>Aspergillus fumigatus</i> is a ubiquitous opportunistic pathogen. We have previously reported that volatile organic compounds (VOCs) produced by <i>A. fumigatus</i> cause delays in metamorphosis, morphological abnormalities, and death in a <i>Drosophila melanogaster&...
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MDPI AG
2023-03-01
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| Series: | Journal of Fungi |
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| Online Access: | https://www.mdpi.com/2309-608X/9/4/402 |
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| author | Hadeel S. Almaliki Mengyao Niu Nancy P. Keller Guohua Yin Joan W. Bennett |
| author_facet | Hadeel S. Almaliki Mengyao Niu Nancy P. Keller Guohua Yin Joan W. Bennett |
| author_sort | Hadeel S. Almaliki |
| collection | DOAJ |
| description | <i>Aspergillus fumigatus</i> is a ubiquitous opportunistic pathogen. We have previously reported that volatile organic compounds (VOCs) produced by <i>A. fumigatus</i> cause delays in metamorphosis, morphological abnormalities, and death in a <i>Drosophila melanogaster</i> eclosion model. Here, we developed <i>A</i>. <i>fumigatus</i> deletion mutants with blocked oxylipin biosynthesis pathways (∆<i>ppoABC</i>) and then exposed the third instar larvae of <i>D. melanogaster</i> to a shared atmosphere with either <i>A. fumigatus</i> wild-type or oxylipin mutant cultures for 15 days. Fly larvae exposed to VOCs from wild-type <i>A</i>. <i>fumigatus</i> strains exhibited delays in metamorphosis and toxicity, while larvae exposed to VOCs from the ∆<i>ppoABC</i> mutant displayed fewer morphogenic delays and higher eclosion rates than the controls. In general, when fungi were pre-grown at 37 °C, the effects of the VOCs they produced were more pronounced than when they were pre-grown at 25 °C. GC–MS analysis revealed that the wild-type <i>A. fumigatus</i> Af293 produced more abundant VOCs at higher concentrations than the oxylipin-deficient strain Af293∆<i>ppoABC</i> did. The major VOCs detected from wild-type Af293 and its triple mutant included isopentyl alcohol, isobutyl alcohol, 2-methylbutanal, acetoin, and 1-octen-3-ol. Unexpectedly, compared to wild-type flies, the eclosion tests yielded far fewer differences in metamorphosis or viability when flies with immune-deficient genotypes were exposed to VOCs from either wild-type or ∆<i>ppoABC</i> oxylipin mutants. In particular, the toxigenic effects of <i>Aspergillus</i> VOCs were not observed in mutant flies deficient in the Toll (<i>spz<sup>6</sup></i>) pathway. These data indicate that the innate immune system of <i>Drosophila</i> mediates the toxicity of fungal volatiles, especially via the Toll pathway. |
| first_indexed | 2024-03-11T04:52:27Z |
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| spelling | doaj.art-de14f72095184ba9bf20569efa4524592023-11-17T19:57:39ZengMDPI AGJournal of Fungi2309-608X2023-03-019440210.3390/jof9040402Mutational Analysis of <i>Aspergillus fumigatus</i> Volatile Oxylipins in a <i>Drosophila</i> Eclosion AssayHadeel S. Almaliki0Mengyao Niu1Nancy P. Keller2Guohua Yin3Joan W. Bennett4Technical Institute of Samawa, Al-Furat Al-Awsat Technical University, Samawa 66001, IraqDepartment of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USADepartment of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USAPeking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences in Weifang, Weifang 261325, ChinaDepartment of Plant Biology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA<i>Aspergillus fumigatus</i> is a ubiquitous opportunistic pathogen. We have previously reported that volatile organic compounds (VOCs) produced by <i>A. fumigatus</i> cause delays in metamorphosis, morphological abnormalities, and death in a <i>Drosophila melanogaster</i> eclosion model. Here, we developed <i>A</i>. <i>fumigatus</i> deletion mutants with blocked oxylipin biosynthesis pathways (∆<i>ppoABC</i>) and then exposed the third instar larvae of <i>D. melanogaster</i> to a shared atmosphere with either <i>A. fumigatus</i> wild-type or oxylipin mutant cultures for 15 days. Fly larvae exposed to VOCs from wild-type <i>A</i>. <i>fumigatus</i> strains exhibited delays in metamorphosis and toxicity, while larvae exposed to VOCs from the ∆<i>ppoABC</i> mutant displayed fewer morphogenic delays and higher eclosion rates than the controls. In general, when fungi were pre-grown at 37 °C, the effects of the VOCs they produced were more pronounced than when they were pre-grown at 25 °C. GC–MS analysis revealed that the wild-type <i>A. fumigatus</i> Af293 produced more abundant VOCs at higher concentrations than the oxylipin-deficient strain Af293∆<i>ppoABC</i> did. The major VOCs detected from wild-type Af293 and its triple mutant included isopentyl alcohol, isobutyl alcohol, 2-methylbutanal, acetoin, and 1-octen-3-ol. Unexpectedly, compared to wild-type flies, the eclosion tests yielded far fewer differences in metamorphosis or viability when flies with immune-deficient genotypes were exposed to VOCs from either wild-type or ∆<i>ppoABC</i> oxylipin mutants. In particular, the toxigenic effects of <i>Aspergillus</i> VOCs were not observed in mutant flies deficient in the Toll (<i>spz<sup>6</sup></i>) pathway. These data indicate that the innate immune system of <i>Drosophila</i> mediates the toxicity of fungal volatiles, especially via the Toll pathway.https://www.mdpi.com/2309-608X/9/4/402<i>Aspergillus fumigatus</i>volatile organic compounds (VOCs)oxylipinseclosion assay<i>Drosophila</i> innate immunity |
| spellingShingle | Hadeel S. Almaliki Mengyao Niu Nancy P. Keller Guohua Yin Joan W. Bennett Mutational Analysis of <i>Aspergillus fumigatus</i> Volatile Oxylipins in a <i>Drosophila</i> Eclosion Assay Journal of Fungi <i>Aspergillus fumigatus</i> volatile organic compounds (VOCs) oxylipins eclosion assay <i>Drosophila</i> innate immunity |
| title | Mutational Analysis of <i>Aspergillus fumigatus</i> Volatile Oxylipins in a <i>Drosophila</i> Eclosion Assay |
| title_full | Mutational Analysis of <i>Aspergillus fumigatus</i> Volatile Oxylipins in a <i>Drosophila</i> Eclosion Assay |
| title_fullStr | Mutational Analysis of <i>Aspergillus fumigatus</i> Volatile Oxylipins in a <i>Drosophila</i> Eclosion Assay |
| title_full_unstemmed | Mutational Analysis of <i>Aspergillus fumigatus</i> Volatile Oxylipins in a <i>Drosophila</i> Eclosion Assay |
| title_short | Mutational Analysis of <i>Aspergillus fumigatus</i> Volatile Oxylipins in a <i>Drosophila</i> Eclosion Assay |
| title_sort | mutational analysis of i aspergillus fumigatus i volatile oxylipins in a i drosophila i eclosion assay |
| topic | <i>Aspergillus fumigatus</i> volatile organic compounds (VOCs) oxylipins eclosion assay <i>Drosophila</i> innate immunity |
| url | https://www.mdpi.com/2309-608X/9/4/402 |
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