Virus-mediated overexpression of peptides in Golden Bantam maize to reduce fall armyworm larval growth
To protect themselves against herbivorous insects and microorganisms, plant species have evolved physical and chemical weapons. The recently discovered PROPEP1 gene, which encodes the precursor of the Pep-1 peptide in maize (Zea mays), has been found to play a crucial role in activating and amplifying the innate immune responses of the plant. Since we know that the peptide regulates the biosynthesis of benzoxazinoids, defense proteins, and jasmonic acid, which are all provide protection against pests such as fall armyworm (Spodoptera frugiperda), we expect that Pep-1 over expression will reduce larval growth. We set out to determine whether the overexpression of Pep-1 with Sugarcane mosaic virus in the maize would increase the plants’ resistance to pests. In order to overexpress the peptide in the maize variety Golden Bantam, a series of cloning processes were performed along with different methods of injections in order to get a high level of viral vector infection. Because there was insufficient time for a bioassay with the cloned Pep-1 gene, the bioassay was performed with plants expressing UyCT3 and LqhIT3 (scorpion venom proteins that are toxic to insects). In this bioassay we found that caterpillars growing on the UyCT3- and LqhIT3-expressing plants experienced significantly reduced growth compared to GFP-expressing control plants. From this result we can deduce that overexpression of cloned peptides in a virus vector can be used to reduce the growth of S. frugiperda.
Working in the Jander Lab at Boyce Thompson Institute this summer has been an invaluable experience, introducing me to the plant world. Each lab member’s passion for science not only made the Jander Lab a welcoming place to work, but a safe place to ask hundreds of questions. Entering the program with little knowledge from high school biology, my mentors Seung Ho and Mahdiyeh took the time to explain every protocol with detail and taught me the importance of laughing at unexpected results. Arming me with new scientific skills and teaching me to use high tech machinery, my mentors challenged my high school thinking styles, pushing me to come up with other possibilities when procedures failed. The PGRP intern experience has offered me a real world setting to test my curiosities in plant defense mechanisms and has allowed me to realistically apply my results to better sustain the health of our future crops and plants.