Plants that attack plants: molecular elucidation of plant parasitism

Obligate parasitic plants in the family Orobanchaceae, such as Striga and Orobanche (including Phelipanche) spp., parasitize important crops and cause severe agricultural damage. Recent molecular studies have begun to reveal how these parasites have adapted to hosts in a parasitic lifecycle. The parasites detect nearby host roots and germinate by a mechanism that seems to have evolved from a conserved germination system found in non-parasites. The development of a specialized infecting organ called a haustorium is a unique feature of plant parasites and is triggered by host compounds and redox signals. Newly developed genomic and genetic resources will facilitate more rapid progress toward a molecular understanding of plant parasitism.

► Strigolactone and karrikin responses share signaling pathways for seed germination.
► Some species respond to specific germination stimulants other than strigolactones.
► Quinone reductases mediate ROS-signaling for haustorium formation.
► Inhibitors of pectinolytic and proteolytic enzymes confer parasite tolerance.
► Genomic resources and transformation protocols for parasitic plants have been developed.