mgr Dominika Dubel

ORCID: 0009-0002-9304-2551

The topic of my dissertation is: „ Defense mechanism of aphids (Hemiptera, Aphidoidea) caused by infection with Bacillus subtilis”

The defense mechanisms of insects against infections caused by microorganisms are not fully understood. Previous studies have focused primarily on model species such as Drosophila melanogaster and Acyrtosiphon pisum. It is known that the defense responses of aphids to infection differ from those of other insects - most likely they have been weakened through evolution to allow the functioning of bacterial symbionts in the aphid body (Renoz et al., 2015).

In the insect body, oxidative stress can be caused by abiotic and biotic stresses. It has been shown that one of the first defense mechanisms of aphids are enzymatic reactions. It is also known that stress can induce behavioral responses, observed mainly as changes in feeding behaviour. So far, it has been studied how infection with the bacterium B. thuringiensis affects the survival of Acyrtosiphon pisum - the infection led to increased aphid mortality, and the individuals that survived were characterized by slower growth. Mortality was caused by endotoxins produced by the bacteria studied (Porcar, 2009). No experiments have been conducted to date to examine the effect of B. subtilis on aphids. B. subitilis is a bacterium commonly found in the environment. It produces a number of substances with bactericidal activity – for example surfactin B (Denoirjean, 2022).

The goal of the research is to study how B. subtilis impacts various species of aphids – their mortality, how they react to the infection and how it may change their feeding behaviours.

Publications:

  1. Denoirjean, T., Ameline, A., Couty, A., Dubois, F., Coutte, F., & Doury, G. (2022). Effects of surfactins, Bacillus lipopeptides, on the behavior of an aphid and host selection by its parasitoid. Pest Management Science, 78(3), 929-937. DOI https://doi.org/10.1002/ps.6702
  2. Porcar, M., Grenier, A. M., Federici, B., & Rahbé, Y. (2009). Effects of Bacillus thuringiensis δ-endotoxins on the pea aphid (Acyrthosiphon pisum). Applied and environmental microbiology, 75(14), 4897-4900. DOI: https://doi.org/10.1128/AEM.00686-09
  3. Renoz, F., Noël, C., Errachid, A., Foray, V., & Hance, T. (2015). Infection dynamic of symbiotic bacteria in the pea aphid Acyrthosiphon pisum gut and host immune response at the early steps in the infection process. PLoS One, 10(3), e0122099. https://doi.org/10.1371/journal.pone.0122099