Sadhvi Mohankumar
Year: 2021
Faculty Advisor: Georg Jander

“The Role of IAA-Amidosynthetase in Mediating Plant Defense Responses via Involvement in Conjugation of Plant Hormones & Amino Acids”

Project Summary:

As a staple food crop and the largest economic agricultural driver in the United States, learning more about the defense pathways of corn, Zea mays, will allow for the development of natural deterrents to crop-killing pests. One such pest is the Fall Armyworm Caterpillar, Spodoptera frugiperda, which typically feed on the leaves of corn and cause major damage. Therefore, by understanding the defense signaling pathways in Z.mays, this research can help support agricultural efforts to sustain an ever-growing human population and its subsequent demand for more food. While known hormones such as jasmonic acid (JA) and auxin (IAA) are widely accepted defense and growth regulators in corn, there are still many important compounds that are unknown. In this experiment, I explored the role of the enzyme IAA-Amidosynthetase that may be responsible for conjugating both JA and IAA with amino acids such as isoleucine (Ile) and ultimately could affect the way Z.mays grows and protects itself from herbivores. I utilized the VIGS (Virus-Induced- Gene- Silencing) technique using a sugarcane mosaic virus vector in two different ways to infect the plants and silence the target gene: using e-coli with biolistic delivery (gene gun) and agrobacterium with inoculation using a syringe. The correctly-infected plants were used to measure gene expression and caterpillar performance which showed trends suggesting that silencing IAA-Amidosynthetase reduced defense signaling; however further studies and analysis of phytohormones and metabolites can shed more light on the specific effects of silencing the IAA-Amidosynthetase on defense and growth in corn.

My Experience:

Over the course of the last ten weeks in the Jander lab I have learned many valuable skills for research and gained key insight about the lifestyle of a researcher. I feel more confident in my understanding of the theory behind corn defense signaling pathways and in my ability to conduct hands-on lab research. Working closely with my mentor, attending various seminars, and meeting other young scientists have allowed me to truly develop my ability to think and work like a scientist that will be essential for my future in science. This experience has taught me new lab techniques such as VIGS (Virus-Induced-Gene- Silencing) that I can take back to my home institution and share with my peers to further develop our research on plant defense mechanisms for the rest of our undergraduate career and beyond.