Abstract
Striga and Orobanche spp. are root parasitic plants belonging to the Orobanchacea. Seeds of these root parasites germinate only when they perceive strigolactones, germination stimulants, produced by and released from roots of plants. So far, more than 10 strigolactones have been isolated from root exudates of various plants. Strigolactones are unstable and rapidly decompose in the soil. Therefore, only the seeds in the vicinity of roots germinate. Plants produce mixtures of strigolactones and the composition of these mixtures may vary with plant species, with cultivars within the same species, with growth stages, and with growth conditions. These quantitative and/or qualitative differences in strigolactone exudation may contribute to host recognition by root parasitic plants. In addition, interactions between the parasites and their hosts after germination may also affect host specificity.
