Delving into the Causes and Effects of Entomopathogenic Endophytic <i>Metarhizium brunneum</i> Foliar Application-Related Mortality in <i>Spodoptera littoralis</i> Larvae
The aim of the current study was to delve into the causes of mortality of <i>Spodoptera littoralis</i> larvae feeding on <i>Metarhizium</i>-colonized plants in the absence of fungal outgrowth on the cadavers as previous studies reported and to elucidate the possible indirect...
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MDPI AG
2020-07-01
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| Series: | Insects |
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| Online Access: | https://www.mdpi.com/2075-4450/11/7/429 |
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| author | Inmaculada Garrido-Jurado David Montes-Moreno Pilar Sanz-Barrionuevo Enrique Quesada-Moraga |
| author_facet | Inmaculada Garrido-Jurado David Montes-Moreno Pilar Sanz-Barrionuevo Enrique Quesada-Moraga |
| author_sort | Inmaculada Garrido-Jurado |
| collection | DOAJ |
| description | The aim of the current study was to delve into the causes of mortality of <i>Spodoptera littoralis</i> larvae feeding on <i>Metarhizium</i>-colonized plants in the absence of fungal outgrowth on the cadavers as previous studies reported and to elucidate the possible indirect effects of this fungus-colonized diet. The effect was evaluated in experiments conducted using leaf discs of colonized plants and in planta using fungus-colonized whole plants. The mortality rates of larvae fed on <i>Metarhizium</i>-colonized melon leaves were 45.0% and 87.5%, and the average survival times were 6.6 and 3.1 days in experiments performed with discs and <i>in planta,</i> respectively. Notably, these mortality levels were not associated with observed apoptosis mediated by caspases 1, 3-7 and 8; thus, further investigation into the possible immune system reaction of the insect after the ingestion of colonized plants is required. The leaf consumption of <i>S. littoralis</i> larvae fed on melon-colonized leaves was lower than that on control plants in the disc experiments but not in experiments conducted <i>in planta</i>. In this regard, in experiments performed <i>in planta</i>, plant damage increased larval mortality in both fungally challenged and control larvae. There was also a meaningful effect of exposure to <i>Metarhizium</i>-colonized melon leaf discs on <i>S. littoralis</i> fitness, with significant reductions in 39.0% and 22.0% in female fecundity and egg fertility, respectively, detected in females emerging from pupae developing from larvae surviving exposure to colonized plant discs; all larvae died in the <i>in planta</i> experiments. Hence, the present work presents new findings revealing the high potential of endophytic entomopathogenic fungi to improve the outcome of foliar applications against chewing insects in the short, mid- and long term, by the reduction of the reproductive potential of surviving adults and reveals new insights into the development of bioassays with whole plants for more detailed evaluation of the impact of these fungi as endophytes used for plant protection. |
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| institution | Directory Open Access Journal |
| issn | 2075-4450 |
| language | English |
| last_indexed | 2024-03-10T18:36:04Z |
| publishDate | 2020-07-01 |
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| spelling | doaj.art-f42df279395b46778a38e9fa3dc79b5b2023-11-20T06:18:27ZengMDPI AGInsects2075-44502020-07-0111742910.3390/insects11070429Delving into the Causes and Effects of Entomopathogenic Endophytic <i>Metarhizium brunneum</i> Foliar Application-Related Mortality in <i>Spodoptera littoralis</i> LarvaeInmaculada Garrido-Jurado0David Montes-Moreno1Pilar Sanz-Barrionuevo2Enrique Quesada-Moraga3Department of Agronomy, ETSIAM, University of Cordoba, Campus de Rabanales, Edificio C4 Celestino Mutis, 14071 Cordoba, SpainDepartment of Agronomy, ETSIAM, University of Cordoba, Campus de Rabanales, Edificio C4 Celestino Mutis, 14071 Cordoba, SpainDepartment of Agronomy, ETSIAM, University of Cordoba, Campus de Rabanales, Edificio C4 Celestino Mutis, 14071 Cordoba, SpainDepartment of Agronomy, ETSIAM, University of Cordoba, Campus de Rabanales, Edificio C4 Celestino Mutis, 14071 Cordoba, SpainThe aim of the current study was to delve into the causes of mortality of <i>Spodoptera littoralis</i> larvae feeding on <i>Metarhizium</i>-colonized plants in the absence of fungal outgrowth on the cadavers as previous studies reported and to elucidate the possible indirect effects of this fungus-colonized diet. The effect was evaluated in experiments conducted using leaf discs of colonized plants and in planta using fungus-colonized whole plants. The mortality rates of larvae fed on <i>Metarhizium</i>-colonized melon leaves were 45.0% and 87.5%, and the average survival times were 6.6 and 3.1 days in experiments performed with discs and <i>in planta,</i> respectively. Notably, these mortality levels were not associated with observed apoptosis mediated by caspases 1, 3-7 and 8; thus, further investigation into the possible immune system reaction of the insect after the ingestion of colonized plants is required. The leaf consumption of <i>S. littoralis</i> larvae fed on melon-colonized leaves was lower than that on control plants in the disc experiments but not in experiments conducted <i>in planta</i>. In this regard, in experiments performed <i>in planta</i>, plant damage increased larval mortality in both fungally challenged and control larvae. There was also a meaningful effect of exposure to <i>Metarhizium</i>-colonized melon leaf discs on <i>S. littoralis</i> fitness, with significant reductions in 39.0% and 22.0% in female fecundity and egg fertility, respectively, detected in females emerging from pupae developing from larvae surviving exposure to colonized plant discs; all larvae died in the <i>in planta</i> experiments. Hence, the present work presents new findings revealing the high potential of endophytic entomopathogenic fungi to improve the outcome of foliar applications against chewing insects in the short, mid- and long term, by the reduction of the reproductive potential of surviving adults and reveals new insights into the development of bioassays with whole plants for more detailed evaluation of the impact of these fungi as endophytes used for plant protection.https://www.mdpi.com/2075-4450/11/7/429ascomycetemycoinsecticidecotton leafwormfitnesscaspasetritrophic interaction |
| spellingShingle | Inmaculada Garrido-Jurado David Montes-Moreno Pilar Sanz-Barrionuevo Enrique Quesada-Moraga Delving into the Causes and Effects of Entomopathogenic Endophytic <i>Metarhizium brunneum</i> Foliar Application-Related Mortality in <i>Spodoptera littoralis</i> Larvae Insects ascomycete mycoinsecticide cotton leafworm fitness caspase tritrophic interaction |
| title | Delving into the Causes and Effects of Entomopathogenic Endophytic <i>Metarhizium brunneum</i> Foliar Application-Related Mortality in <i>Spodoptera littoralis</i> Larvae |
| title_full | Delving into the Causes and Effects of Entomopathogenic Endophytic <i>Metarhizium brunneum</i> Foliar Application-Related Mortality in <i>Spodoptera littoralis</i> Larvae |
| title_fullStr | Delving into the Causes and Effects of Entomopathogenic Endophytic <i>Metarhizium brunneum</i> Foliar Application-Related Mortality in <i>Spodoptera littoralis</i> Larvae |
| title_full_unstemmed | Delving into the Causes and Effects of Entomopathogenic Endophytic <i>Metarhizium brunneum</i> Foliar Application-Related Mortality in <i>Spodoptera littoralis</i> Larvae |
| title_short | Delving into the Causes and Effects of Entomopathogenic Endophytic <i>Metarhizium brunneum</i> Foliar Application-Related Mortality in <i>Spodoptera littoralis</i> Larvae |
| title_sort | delving into the causes and effects of entomopathogenic endophytic i metarhizium brunneum i foliar application related mortality in i spodoptera littoralis i larvae |
| topic | ascomycete mycoinsecticide cotton leafworm fitness caspase tritrophic interaction |
| url | https://www.mdpi.com/2075-4450/11/7/429 |
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