A roadmap of haustorium morphogenesis in parasitic plants.

Parasitic plants invade their host through their invasive organ, the haustoria. This organ connects to the vasculature of the host roots and hijacks water and nutrients. Although plant parasitism has evolved independently in plants, haustoria formation follows a similar mechanism throughout different plant species, highlighting the developmental plasticity of plant tissues. Here, we compare three types of haustoria formed by root and shoot in the plant parasites Striga and Cuscuta. We discuss mechanisms underlying the interactions with their hosts and how different approaches have contributed to major understanding of haustoria formation and host invasion. We also illustrate the role of auxin and cytokinin in controlling this process.