Plant responses to aphid infestation: shed light on plant immunity regulation

Abstract

Aphids are devastating plant sap-feeding insects. These insects cause direct feeding damage and transmit the majority of plant viruses, resulting in significant yield losses, particularly in staple food crops. Interestingly, most aphid species are restricted to one or few host plants. However, some species, many of which are of agricultural importance, can infest a wide range of plant species.

An important observation is that aphids spend a considerable time on non-host plants, where they probe the leaf tissue and secrete saliva, but for unknown reasons are unable to ingest phloem sap. These findings suggest that aphids, like plant pathogens, interact with non-host plants at the molecular level, but potentially are not successful in suppressing plant defenses and/or releasing nutrients. Recent work suggests that aphids, like plant pathogens, secrete effectors into their host plants to manipulate host cell processes and impact the ability to infest plants. Therefore, my project was to investigate the role of plant cellular processes in determining aphid host range.

We are comparing interactions of economically important aphid species, Myzus persicae (green peach aphid) Myzus cerasi (black cherry aphid) and Rhopalosiphum padi (bird cherry oat aphid) with host and non-host plants. More specifically, we are characterizing host, versus non-host plant responses upon aphid interaction by investigating the activation of plant defences and changes in plant gene expression. Understanding the role of both plant and aphid proteins in different types of interactions could provide us with key insight that are needed to develop novel strategies to control aphid infestations.