The effect of host-root-derived chemical signals on the germination of parasitic plants

Abstract

The parasitic plants Orobanche and Striga spp. are holo- and hemiparasites, which largely depend on a host plant to obtain their nutrients and water. The seeds of these parasites can only germinate in the presence of a chemical compound that is exuded from the roots of their host. These compounds are called germination stimulants and so far several of these compounds have been identified in the exudates of hosts (and false hosts) of several Orobanche and Striga species. The germination stimulants play an important role in fine-tuning of the lifecycle of the parasites to that of their hosts. In this chapter we describe the processes that play a role in this interaction, for example how the germination stimulants are produced by the host and how they are perceived by the parasite. Also we discuss the possible importance of the germination stimulants in determining host specificity