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Maintaining Biological Cultures and Measuring Gene Expression in Aphis nerii: A Non-model System for Plant-insect Interactions
Published on: August 31, 2018
Aphids alter host-plant nitrogen isotope fractionation
Alex C C Wilson1, Leonel da S L Sternberg, Katherine B Hurley
1Department of Biology, University of Miami, Coral Gables, FL 33146, USA. acwilson@bio.miami.edu
Summary
Green peach aphids (Myzus persicae) show lower nitrogen-15 (15N) levels than their host plants. Aphid colonization also alters plant nitrogen metabolism, affecting the plant's 15N signature.
Area of Science:
- Ecology
- Stable Isotope Ecology
- Plant-Insect Interactions
Background:
- Fluid-feeding organisms like insects and parasites often exhibit depleted nitrogen-15 (15N) stable isotope ratios compared to their diets.
- Understanding the mechanisms behind this isotopic trophic depletion in plant-feeder systems is crucial but often overlooked.
Purpose of the Study:
- To investigate the nitrogen stable-isotope dynamics in the green peach aphid (Myzus persicae) and its brassicaceous host plants.
- To elucidate the mechanisms driving isotopic depletion in this herbivore-host system and the impact of aphid colonization on host nitrogen metabolism.
Main Methods:
- Quantified nitrogen-15 (15N) stable isotope signatures in aphids and their host plants.
- Assessed the relationship between aphid isotopic depletion and host plant nitrogen content.
- Measured nitrate reductase activity in colonized versus uncolonized plants to understand host nitrogen metabolism alterations.
Main Results:
- Myzus persicae consistently showed a depletion of over 6‰ in 15N relative to their host plants.
- Aphid-colonized plants were enriched in 15N (1.5‰–2.0‰) compared to uncolonized controls.
- Aphid 15N depletion and host 15N enrichment were uncoupled processes, with depletion linked to host nitrogen content.
- Nitrate reductase activity was twofold higher in colonized plants, indicating altered host nitrogen metabolism.
Conclusions:
- Isotopic separation between aphids and hosts is dependent on nitrogen availability.
- Aphid colonization significantly alters host plant nitrogen metabolism and its stable isotope signature.
- This study provides a metabolic framework for future research on aphid manipulation of host nitrogen metabolism.
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