In vitro culture of Orobanche crenata

Orobanche species are serious holoparasitic angiosperm weeds that cause heavy direct damage to many important crops. Thus, Orobanche crenata Forsk. is considered an important constraint to legume crops in the Mediterranean area. Successful applications of biotechnology to biotic constraints facing legume crops require both a good biological knowledge of the target species and the mechanisms underlying resistance/tolerance to these stresses. The study of hostorobanche interaction requires the development of an in vitro infection system, free of microorganism contaminations, with full regeneration of the plant parasite. Nevertheless, growing these parasitic plants in vitro is difficult, because of their dependence on a connection to hosts for normal development, and because of their specific germination requirements. An in vitro system has been developed that allows the production of partially differentiated calli of O. crenata. This study describes the influence of different plant growth media in association with different plant growth regulators on germination and development in vitro of calli from O. crenata seeds. Thus, the effect of giberellic acid on germination of O. crenata seeds varied with concentration and type of plant growth media used. These in vitro growth conditions affected also the period of germination and the structure of calli and protrusions produced. These in vitro structures may provide a useful system for studying the molecular steps of the infection whereby O. crenata attaches to and penetrates Faba bean root.