Plant defense regulated by EDS1 in response to herbivory attack

Abstract

Spodoptera exigua, is a beet armyworm that causes extensive damage to farm crops. They are also resistant to most insecticides, so a molecular approach is necessary to combat their damage. Plant response to stresses are carried out locally and systemically by jasmonates and salicyclic acid. Eds 1-2 and are genes along these pathways that regulate the production of jasmonic acid and salicylic acid. It has already been established by previous research that mutations in eds 1-2 increase salicylic acid accumulation. To determine the extent, and effect of mutations on genes along these pathways, experiments were performed on three different Arabidopsis thaliana genomes (Col – wild type, and mutations on eds 1-2,). The cannibalism assay was conducted to see the extent of cannibalism between the insects when allowed to feed on these plants, and the plant performance assay to determine the growth of plants if not for the damage caused by insects. The insect assay results showed there is a greater variance between actual growth and expected growth in Col, as compared to and eds 1-2. That is, the insect did not cause much damage to the eds 1-2 plants which suggests that it may have not liked to eat the eds 1-2 due to increased accumulation of salicylic acid as the others. The cannibalism assay results suggest a possible acclimatization of insects to the defense response, or a reduced defense response to a second herbivory attack in a short period of time. Further research involving the measurement of the products produced by these defense pathways at different timepoints will help answer the questions if the amount of salicylic acid produced a second time is less, and if so what is the minimum time before the plant is able to produce the original amount of salicylic acid. This can also help determine if the insects get acclimatized to the salicylic acid or not.