Aseptic broomrape infection of tomato root culture

The parasitic plants of the genus Orobanche (broomrape) are important pathogens of numerous agricultural crops throughout the world. The understanding of biochemical mechanisms involved in the penetration of Orobanche haustorium into host root tissues faces difficulties due to the presence of microorganisms. Here we describe an aseptic in vitro system, in which normal broomrape seedlings infect host roots grown in culture, instead of the previously reported infection of intact host plants by Orobanche calli. This system is based on divided Petri plates with two different culture media: one part of the dish contains a rich medium suitable for the support of host root culture, the other part contains a medium with no organic nutrients and no hormones and is therefore suitable for infection of host roots by Orobanche. Roots that are supported by the first medium pass to the other side of the petri dish where they stimulate broomrape seed germination and are infected by the emerging broomrape seedlings.