“Exploring Novel Strategies for Aphid Pest Control”
Aphids, comprised of 4,000 species, are serious agricultural and forestry pests. Aphids can damage plants by directly sucking plant phloem sap, vectoring plant viruses, and providing a hotbed for growth of sooty mold by their honeydew. Current pest control methods involve spraying varying amounts of chemical pesticides which have introduced foreign chemicals that pollute the environment and infected plants that people eventually consume. My project aims to explore safer techniques that includes two RNA silencing methods: 1) plant-mediated virus-induced gene silencing (VIGS) and 2) morpholino-mediated gene silencing. Plant-mediated VIGS involves using Agrobacterium transformation to infect plants with Tobacco rattle virus (TRV) that carries double-stranded RNAs targeting an aphid gene. The goal is for aphids to ingest this double-stranded RNA through natural feeding on VIGS plants, in turn blocking the target gene expression via RNAi, and ultimately decreasing aphid population. We are still in the phase of screening target gene candidates that can effectively reduce aphid survivorship via the plant mediated VIGS method. Morpholinos, also known as phosphorodiamidate morpholino oligomers (PMOs), have been used as gene silencing reagents. We aim to explore morpholinos for their potential to control aphids. PMOs are synthetic oligonucleotides that contain a backbone of morpholine rings connected by phosphorodiamidate linkages. PMOs function by complementary binding to the target mRNA sequence, thereby blocking mRNA translation or modifying pre-mRNA splicing. We designed a PMOs to targeting an exon-intron junction of aphid gene white, aiming to alter its exon splicing. Alteration to white by this PMO will result either dysfunction or reduced expression. Thus, we expect aphids who ingest this PMO to demonstrate discolored eyes because white has been shown to be responsible for eye color in other insects. We have designed experiments that will allow for optimal uptake of PMO, using techniques such as topical delivery, gene gun bombardment, artificial diet, and microinjections. After such experiments, we have observed lighter eye phenotypes but have since complemented with biological replicate experiments and qPCR/PCR experiments to confirm the altering of the gene white. These results have looked promising, but we are still far away from eliminating all possible conflicting variables and confirming the efficacy of morpholinos for controlling aphid pests.
Not only has the Boyce Thompson Institute experience expanded my scope of scientific knowledge, but it has also sharpened my abilities to regard the minuscule details of lab work and experiment management. I now know what it means to design sufficient control experiments and limit sources of potential cross contamination, the little things that lead the experiment in the right direction. It is easy in class to get carried away in the unimportant details of science like memorizing the steps to the scientific method or memorizing the amino acids. But with the help of my mentor, this program provided the perfect space to apply the concepts I have learned in introductory science course to experiments in real life. Working with my mentor has shown me what it means to actually pursue research because in the work there are so many ups and downs and variables that are not in your control. But it’s all about how you use what you have to your advantage to try and contribute to the scientific world. I definitely got to experience first-hand some of the concepts I read about in my AP Biology textbooks. Most importantly, this program has raised my confidence level in pursuing research science to the point where I’m excited to start my own journey into scientific research fields.