The Symbiotic Bacteria—<i>Xenorhabdus nematophila</i> All and <i>Photorhabdus luminescens</i> H06 Strongly Affected the Phenoloxidase Activation of Nipa Palm Hispid, <i>Octodonta nipae</i> (Coleoptera: Chrysomelidae) Larvae
Symbiotic bacteria form a mutualistic relationship with nematodes and are pathogenic to many insect pests. They kill insects using various strategies to evade or suppress their humoral and cellular immunity. Here we evaluate the toxic effects of these bacteria and their secondary metabolites on the...
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MDPI AG
2023-03-01
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| Online Access: | https://www.mdpi.com/2076-0817/12/4/506 |
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| author | Nafiu Bala Sanda Youming Hou |
| author_facet | Nafiu Bala Sanda Youming Hou |
| author_sort | Nafiu Bala Sanda |
| collection | DOAJ |
| description | Symbiotic bacteria form a mutualistic relationship with nematodes and are pathogenic to many insect pests. They kill insects using various strategies to evade or suppress their humoral and cellular immunity. Here we evaluate the toxic effects of these bacteria and their secondary metabolites on the survival and phenoloxidase (PO) activation of <i>Octodonta nipae</i> larvae using biochemical and molecular methods. The results show <i>P. luminescens</i> H06 and <i>X. nematophila</i> All treatments caused significant reductions in the number of <i>O. nipae</i> larvae in a dose-dependent manner. Secondly, the <i>O. nipae</i> immune system recognizes symbiotic bacteria at early and late stages of infection via the induction of C-type lectin. Live symbiotic bacteria significantly inhibit PO activity in <i>O. nipae</i> whereas heat-treated bacteria strongly increase PO activity. Additionally, expression levels of four <i>O. nipae</i> proPhenoloxidase genes following treatment with <i>P. luminescens</i> H06 and <i>X. nematophila</i> All were compared. We found that the expression levels of all proPhenoloxidase genes were significantly down-regulated at all-time points. Similarly, treatments of <i>O. nipae</i> larvae with metabolites benzylideneacetone and oxindole significantly down-regulated the expression of the PPO gene and inhibited PO activity. However, the addition of arachidonic acid to metabolite-treated larvae restored the expression level of the PPO gene and increased PO activity. Our results provide new insight into the roles of symbiotic bacteria in countering the insect phenoloxidase activation system. |
| first_indexed | 2024-03-11T04:39:56Z |
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| language | English |
| last_indexed | 2024-03-11T04:39:56Z |
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| spelling | doaj.art-fdff906dc9f74524a48902a1b238adf62023-11-17T20:47:42ZengMDPI AGPathogens2076-08172023-03-0112450610.3390/pathogens12040506The Symbiotic Bacteria—<i>Xenorhabdus nematophila</i> All and <i>Photorhabdus luminescens</i> H06 Strongly Affected the Phenoloxidase Activation of Nipa Palm Hispid, <i>Octodonta nipae</i> (Coleoptera: Chrysomelidae) LarvaeNafiu Bala Sanda0Youming Hou1State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, ChinaState Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, ChinaSymbiotic bacteria form a mutualistic relationship with nematodes and are pathogenic to many insect pests. They kill insects using various strategies to evade or suppress their humoral and cellular immunity. Here we evaluate the toxic effects of these bacteria and their secondary metabolites on the survival and phenoloxidase (PO) activation of <i>Octodonta nipae</i> larvae using biochemical and molecular methods. The results show <i>P. luminescens</i> H06 and <i>X. nematophila</i> All treatments caused significant reductions in the number of <i>O. nipae</i> larvae in a dose-dependent manner. Secondly, the <i>O. nipae</i> immune system recognizes symbiotic bacteria at early and late stages of infection via the induction of C-type lectin. Live symbiotic bacteria significantly inhibit PO activity in <i>O. nipae</i> whereas heat-treated bacteria strongly increase PO activity. Additionally, expression levels of four <i>O. nipae</i> proPhenoloxidase genes following treatment with <i>P. luminescens</i> H06 and <i>X. nematophila</i> All were compared. We found that the expression levels of all proPhenoloxidase genes were significantly down-regulated at all-time points. Similarly, treatments of <i>O. nipae</i> larvae with metabolites benzylideneacetone and oxindole significantly down-regulated the expression of the PPO gene and inhibited PO activity. However, the addition of arachidonic acid to metabolite-treated larvae restored the expression level of the PPO gene and increased PO activity. Our results provide new insight into the roles of symbiotic bacteria in countering the insect phenoloxidase activation system.https://www.mdpi.com/2076-0817/12/4/506symbiotic bacteriaproPhenoloxidase activation<i>Octodonta nipae</i>secondary metabolitesimmune responseEntomopathogenic nematodes |
| spellingShingle | Nafiu Bala Sanda Youming Hou The Symbiotic Bacteria—<i>Xenorhabdus nematophila</i> All and <i>Photorhabdus luminescens</i> H06 Strongly Affected the Phenoloxidase Activation of Nipa Palm Hispid, <i>Octodonta nipae</i> (Coleoptera: Chrysomelidae) Larvae Pathogens symbiotic bacteria proPhenoloxidase activation <i>Octodonta nipae</i> secondary metabolites immune response Entomopathogenic nematodes |
| title | The Symbiotic Bacteria—<i>Xenorhabdus nematophila</i> All and <i>Photorhabdus luminescens</i> H06 Strongly Affected the Phenoloxidase Activation of Nipa Palm Hispid, <i>Octodonta nipae</i> (Coleoptera: Chrysomelidae) Larvae |
| title_full | The Symbiotic Bacteria—<i>Xenorhabdus nematophila</i> All and <i>Photorhabdus luminescens</i> H06 Strongly Affected the Phenoloxidase Activation of Nipa Palm Hispid, <i>Octodonta nipae</i> (Coleoptera: Chrysomelidae) Larvae |
| title_fullStr | The Symbiotic Bacteria—<i>Xenorhabdus nematophila</i> All and <i>Photorhabdus luminescens</i> H06 Strongly Affected the Phenoloxidase Activation of Nipa Palm Hispid, <i>Octodonta nipae</i> (Coleoptera: Chrysomelidae) Larvae |
| title_full_unstemmed | The Symbiotic Bacteria—<i>Xenorhabdus nematophila</i> All and <i>Photorhabdus luminescens</i> H06 Strongly Affected the Phenoloxidase Activation of Nipa Palm Hispid, <i>Octodonta nipae</i> (Coleoptera: Chrysomelidae) Larvae |
| title_short | The Symbiotic Bacteria—<i>Xenorhabdus nematophila</i> All and <i>Photorhabdus luminescens</i> H06 Strongly Affected the Phenoloxidase Activation of Nipa Palm Hispid, <i>Octodonta nipae</i> (Coleoptera: Chrysomelidae) Larvae |
| title_sort | symbiotic bacteria i xenorhabdus nematophila i all and i photorhabdus luminescens i h06 strongly affected the phenoloxidase activation of nipa palm hispid i octodonta nipae i coleoptera chrysomelidae larvae |
| topic | symbiotic bacteria proPhenoloxidase activation <i>Octodonta nipae</i> secondary metabolites immune response Entomopathogenic nematodes |
| url | https://www.mdpi.com/2076-0817/12/4/506 |
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