The Effects of Species and Diet on Metabolites Present in Aphid Saliva

Despite their minute physical size, aphids are an important, complex family of insects (Aphididae: Hemiptera) that includes many agronomically important pests. Most aphids feed on the phloem of plants using their specialized mouthpart called a stylet. While feeding, aphids are also injecting their saliva, rich in proteins and other components known to impact the plant-aphid relationship. Many of the proteins present in aphid saliva allow the aphid to continue feeding by dampening the host plant’s defensive reaction. It is understood that host plant and aphid species impact the composition of saliva. However, most other components of aphid saliva, like metabolites, are not understood well. A range of aphid species and host plants were compared to see if diet or aphid species influences the metabolites present in saliva. Saliva samples were processed using Liquid Chromatography and Mass Spectrometry in a non-targeted metabolomics approach. Results demonstrate that the host plant on which the generalist aphid species, Myzus persicae, is feeding does impact adult aphid size and survival. While diet did seem to impact the aphid saliva composition, surviving aphids did not always produce abundant saliva with unique compounds. Additionally, saliva from five aphid species with various ecological preferences was compared, revealing that while they share a portion of unique mass features, species also influences composition of metabolic features in the saliva. Further analysis of this data set needs to be performed to understand the trends seen in metabolite composition across species and host plants. These conclusions demonstrate the complexity of aphid saliva and warrant further investigation into the metabolome of aphid saliva to focus on metabolites that could be assisting the aphid while feeding.

This summer internship at Boyce Thompson Institute was not only fun but also highly educational and eye-opening. Getting the hands-on experience of working in a professional lab as an undergraduate student has helped me to gain new skills and confidence. Having my mentor to guide me through the project gave me stability but also granted me a new connection and friend in the scientific community. The community that was created by the REU students was very encouraging. This internship reinforced my decision that I want to continue in my educational journey and pursue a graduate degree in plant biochemistry. These experiences and the people I met have helped me to know more of what to expect as a grad student and answered my questions honestly. This internship has cultivated my interests in plant biology and has helped me to feel more prepared for my future in research.