Kaitlin Marry
Marry, Kaitlin
Year: 2022
Faculty Advisor: Clare Casteel

“Viruses and their vectors: Investigating the effects of Pea enation mosaic virus (PEMV) on Acyrthosiphon pisum

Project Summary:

Viral diseases contribute to large economic losses in agriculture worldwide and threaten global food security each year. Viruses require vectors for transmission; therefore, managing the vectors may profoundly affect their dissemination and their negative impacts on agriculture. Two viruses of interest, Pea enation mosaic virus (PEMV) and Bean yellow mosaic virus (BYMV), both infect legumes and are vectored by Acyrthosiphon pisum, commonly known as the pea aphid. It is well known that all aphids depend on an obligate endosymbiont, Buchnera aphidicola, for nutrients. Recently it was shown that the B. aphidicola protein GroEL is found in aphid saliva and can trigger pattern-triggered immunity (PTI). We hypothesized that coinfection would lower the B. aphidicola titer and the induction of PTI to increase their transmission, which may have negative impacts on the aphid. To test this, we measured groEL expression, B. aphidicola titer, and aphid fecundity on BYMV- and PEMV- infected plants and control plants. P. sativum were rub inoculated with in-vitro synthesized transcripts of an infectious clone of PEMV or agro-inoculated with an infectious clone of BYMV. The infection was verified 14 days later, then five adult A. pisum were placed infected and healthy plants. After 24 hours, the adults were removed, and 12 nymphs were left to develop for the next seven days. To measure groEL expression, RNA was extracted from the aphids, cDNA was synthesized, and RT-qPCR was performed using groEL-specific primers. From these measurements, the relative transcript abundance was calculated using a standard curve from serial dilutions of cDNA. To measure fecundity one adult aphid was left on the plant for 72 additional hours and the nymphs were counted. Preliminary data shows that fecundity is negatively impacted by PEMV.

My Experience:

This summer I was met with an array of challenges that pushed me outside my comfort zone.  Before this internship, I had no experience with viruses or their vectors. The first days were incredibly overwhelming as I learned brand new procedures and read papers in which I had to google half the words. However, I was met with a team that encouraged my questions and were always patient with me. I learned a great deal of things that I liked and conversely a bunch that I did not. I had meaningful conversations about graduate school with my mentor, which have propelled me to chase after my passion for science. Most importantly I was able to create a community with my fellow interns and my lab that I can proudly call my friends.