The influence of singlet oxygen signaling on plant responses to the green peach aphid Myzus persicae

The focus of this project is the role of a common but under-studied reactive oxygen species (ROS), singlet oxygen (1O2), in plant signaling responses to aphid attack. Singlet oxygen is a short-lived and highly reactive form of molecular oxygen that is generated in plant chloroplasts, and that accumulates to higher-than normal levels in response to certain environmental stresses such as excess light. This ROS mediates signaling from the chloroplast to the nucleus, reprogramming nuclear gene expression. Many aspects of this 1O2-dependent retrograde signaling are mediated by the Executer 1 (EX1) protein, but other EX1-independent pathways have also been reported. EX1-dependent signaling and possibly also other 1O2-responsive signaling pathways contribute to plant adaptation to high light stress, but their influence on biotic stress responses is largely unexplored. Here, we examine the influence of EX1 on transcriptional responses to the green peach aphid Myzus persicae in the model plant Arabidopsis thaliana, and also examine markers of other 1O2-responsive signaling pathways. Our results suggest new roles for 1O2 in biotic stress, and new mechanisms of plant response to aphid attack.