Root Colonization by Fungal Entomopathogen Systemically Primes Belowground Plant Defense against Cabbage Root Fly
Entomopathogenic fungi infect insects via spores but also live inside plant tissues as endophytes. Frequently, colonization by entomopathogens provides plants with increased resistance against insects, but the mechanisms are little understood. This study investigated direct, local, and systemic root...
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MDPI AG
2022-09-01
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| Series: | Journal of Fungi |
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| Online Access: | https://www.mdpi.com/2309-608X/8/9/969 |
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| author | Catalina Posada-Vergara Katharina Lohaus Mohammad Alhussein Stefan Vidal Michael Rostás |
| author_facet | Catalina Posada-Vergara Katharina Lohaus Mohammad Alhussein Stefan Vidal Michael Rostás |
| author_sort | Catalina Posada-Vergara |
| collection | DOAJ |
| description | Entomopathogenic fungi infect insects via spores but also live inside plant tissues as endophytes. Frequently, colonization by entomopathogens provides plants with increased resistance against insects, but the mechanisms are little understood. This study investigated direct, local, and systemic root-mediated interactions between isolates of the fungus <i>Metarhizium brunneum</i> and larvae of the cabbage root fly (CRF) <i>Delia radicum</i> attacking <i>Brassica napus</i> plants. All fungal isolates infected CRF when conidia were present in the soil, leading to 43–93% mortality. Locally, root-associated <i>M. brunneum</i> isolates reduced herbivore damage by 10–20% and in three out of five isolates caused significant insect mortality due to plant-mediated and/or direct effects. A split-root experiment with isolate Gd12 also demonstrated systemic plant resistance with significantly reduced root collar damage by CRF. LC-MS analyses showed that fungal root colonization did not induce changes in phytohormones, while herbivory increased jasmonic acid (JA) and glucosinolate concentrations. Proteinase inhibitor gene expression was also increased. Fungal colonization, however, primed herbivore-induced JA and the expression of the JA-responsive plant defensin 1.2 (PDF1.2) gene. We conclude that root-associated <i>M. brunneum</i> benefits plant health through multiple mechanisms, such as the direct infection of insects, as well as the local and systemic priming of the JA pathway. |
| first_indexed | 2024-03-09T23:30:39Z |
| format | Article |
| id | doaj.art-d5ab55219f7241d4957bba14c988bd29 |
| institution | Directory Open Access Journal |
| issn | 2309-608X |
| language | English |
| last_indexed | 2024-03-09T23:30:39Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Fungi |
| spelling | doaj.art-d5ab55219f7241d4957bba14c988bd292023-11-23T17:10:05ZengMDPI AGJournal of Fungi2309-608X2022-09-018996910.3390/jof8090969Root Colonization by Fungal Entomopathogen Systemically Primes Belowground Plant Defense against Cabbage Root FlyCatalina Posada-Vergara0Katharina Lohaus1Mohammad Alhussein2Stefan Vidal3Michael Rostás4Agricultural Entomology, Department of Crop Sciences, University of Göttingen, Grisebachstr 6, 37077 Göttingen, GermanyAgricultural Entomology, Department of Crop Sciences, University of Göttingen, Grisebachstr 6, 37077 Göttingen, GermanyMolecular Phytopathology and Mycotoxin Research, Department of Crop Sciences, University of Göttingen, Grisebachstr 6, 37077 Göttingen, GermanyAgricultural Entomology, Department of Crop Sciences, University of Göttingen, Grisebachstr 6, 37077 Göttingen, GermanyAgricultural Entomology, Department of Crop Sciences, University of Göttingen, Grisebachstr 6, 37077 Göttingen, GermanyEntomopathogenic fungi infect insects via spores but also live inside plant tissues as endophytes. Frequently, colonization by entomopathogens provides plants with increased resistance against insects, but the mechanisms are little understood. This study investigated direct, local, and systemic root-mediated interactions between isolates of the fungus <i>Metarhizium brunneum</i> and larvae of the cabbage root fly (CRF) <i>Delia radicum</i> attacking <i>Brassica napus</i> plants. All fungal isolates infected CRF when conidia were present in the soil, leading to 43–93% mortality. Locally, root-associated <i>M. brunneum</i> isolates reduced herbivore damage by 10–20% and in three out of five isolates caused significant insect mortality due to plant-mediated and/or direct effects. A split-root experiment with isolate Gd12 also demonstrated systemic plant resistance with significantly reduced root collar damage by CRF. LC-MS analyses showed that fungal root colonization did not induce changes in phytohormones, while herbivory increased jasmonic acid (JA) and glucosinolate concentrations. Proteinase inhibitor gene expression was also increased. Fungal colonization, however, primed herbivore-induced JA and the expression of the JA-responsive plant defensin 1.2 (PDF1.2) gene. We conclude that root-associated <i>M. brunneum</i> benefits plant health through multiple mechanisms, such as the direct infection of insects, as well as the local and systemic priming of the JA pathway.https://www.mdpi.com/2309-608X/8/9/969endophytic entomopathogenic fungi<i>Delia radicum</i><i>Metarhizium brunneum</i><i>Brassica napus</i>plant-fungal-insect interactionssplit-root |
| spellingShingle | Catalina Posada-Vergara Katharina Lohaus Mohammad Alhussein Stefan Vidal Michael Rostás Root Colonization by Fungal Entomopathogen Systemically Primes Belowground Plant Defense against Cabbage Root Fly Journal of Fungi endophytic entomopathogenic fungi <i>Delia radicum</i> <i>Metarhizium brunneum</i> <i>Brassica napus</i> plant-fungal-insect interactions split-root |
| title | Root Colonization by Fungal Entomopathogen Systemically Primes Belowground Plant Defense against Cabbage Root Fly |
| title_full | Root Colonization by Fungal Entomopathogen Systemically Primes Belowground Plant Defense against Cabbage Root Fly |
| title_fullStr | Root Colonization by Fungal Entomopathogen Systemically Primes Belowground Plant Defense against Cabbage Root Fly |
| title_full_unstemmed | Root Colonization by Fungal Entomopathogen Systemically Primes Belowground Plant Defense against Cabbage Root Fly |
| title_short | Root Colonization by Fungal Entomopathogen Systemically Primes Belowground Plant Defense against Cabbage Root Fly |
| title_sort | root colonization by fungal entomopathogen systemically primes belowground plant defense against cabbage root fly |
| topic | endophytic entomopathogenic fungi <i>Delia radicum</i> <i>Metarhizium brunneum</i> <i>Brassica napus</i> plant-fungal-insect interactions split-root |
| url | https://www.mdpi.com/2309-608X/8/9/969 |
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