Epsilon Archive for Student Projects

Abstract

Parasitic plants have the ability to invade other plant species to feed on them. The parasitic lifestyle can only occur due to the formation of an invasive structure denominated haustorium. Haustorium formation allows
parasiticplants to feed on their host by a vasculature connection where the exchange of nutrients and smallmolecules occurs. For an haustorium to be formed, the host tissues need to be invaded using cell wall modifying enzymes such as peroxidases and the force of rapid cell proliferation. ROS are known to be important signalling molecules, playing important roles in root growth development mediating cell division and cell differentiation. An accumulation of ROS happens in the initiation of haustoria formation, however, the role of this accumulation in haustoria formation is not known. A fascinating characteristic of some parasitic plants is the ability to infect and form vascular connections with distantly related species, therefore surpassing tissue incompatibility. In addition, some parasitic plants appear to have selfrecognition mechanisms that will prevent them from infecting themselves and parasitic plants of the same species. The facultative root parasite Phtheirospermum japonicum is a model parasitic plant that infects distantly related species and does not infect itself. The aim of this thesis was to understand ROS dynamics in haustoria formation and if ROS can be involved in the self-recognition mechanism. The approach includes the imaging of ROS species during haustoria formation and the analysis of transcriptomic data. Data obtained show that some ROS have a localized signal for haustoria and xylem bridge formation, suggesting the involvement of ROS as signalling molecules necessary for haustoria formation.