P-119 - Defensive duel: The role of fall armyworm saliva in altering sorghum defenses

Insects have evolved diverse strategies to overcome plant defenses. During feeding, they secrete salivary factors or effectors that reprogram host cell processes and either suppress or trigger plant defense responses. Sorghum (Sorghum bicolor), a major cereal crop grown worldwide for food, feed, and/or fuel, is attacked by fall armyworm (FAW; Spodoptera frugiperda), a devastating pest of sorghum. Previously, we have shown that the sorghum flavonoids, which are a class of phenylpropanoids, have a detrimental impact on FAW growth and survival. As a counter-defense mechanism, FAW saliva can suppress sorghum flavonoid-based defenses. To extend our work, we utilized a quantitative proteomics approach (LC-MS/MS) comparing the salivary proteome of larvae reared on a sorghum wild-type (WT; RTx430) diet versus an artificial diet. A total of ~1,200 proteins were identified, with 85 showing differential expression between diet groups. Interestingly, several key proteins in FAW saliva exhibited diet-specific expression. Among these, a large array of proteins was associated with hydrolase and oxidoreductase activities. Of the proteins described with hydrolase activity, many were identified as having putative lipase activity.  Understanding both plant defense mechanisms and herbivore countermeasures will provide a comprehensive framework for studying plant-insect interactions and developing sustainable pest control strategies.