The Use of Arabidopsis to Study Interactions between Parasitic Angiosperms and Their Plant Hosts

Abstract

Parasitic plants invade host plants in order to rob them of water, minerals and nutrients. The consequences to the infected hosts can be debilitating and some of the world's most pernicious agricultural weeds are parasitic. Parasitic genera of the Scrophulariaceae and Orobanchaceae directly invade roots of neighboring plants via underground structures called haustoria. The mechanisms by which these parasites identify and associate with host plants present unsurpassed opportunities for studying chemical signaling in plant-plant interactions. Seeds of some parasites require specific host factors for efficient germination, thereby insuring the availability of an appropriate host root prior to germination. A second set of signal molecules is required to induce haustorium development and the beginning of heterotrophy. Later stages in parasitism also require the presence of host factors, although these have not yet been well characterized. Arabidopsis is being used as a model host plant to identify genetic loci associated with stimulating parasite germination, haustorium development, and parasite support. Arabidopsis is also being employed to explore how host plants respond to parasite attack. Current methodologies and recent findings in Arabidopsis - parasitic plant interactions will be discussed.

Agrobacterium tumefaciens and Agrobacterium rhizogenes transformed roots of the parasitic plant Triphysaria versicolor retain parasitic competence

“…At the other extreme are facultative parasites like Triphysaria and Rhinanthus that are able to survive as free-living plants but will parasitize a host plant if one is available (Atsatt and Strong 1970;Gibson and Watkinson 1989). Typical of facultative parasites, Triphysaria has a broad host range that includes at least 20 monocotyledon and eudicot families, including maize, rice and Arabidopsis (Atsatt and Strong 1970;Goldwasser et al 2002).…”

Unexpected fast development of branched broomrape on slow-growing Brassicaceae

“…Among Brassicaceae weeds, thale cress (Arabidopsis thaliana (L.) Heynh.) is widely used as a useful model for the study of plant biology, including plantplant interactions (Mienke et al 1998;Goldwasser et al 2002;Bouwmeester et al 2003). P. ramosa infection on A. thaliana is similar to that on agricultural hosts.…”

Trans‐specific gene silencing between host and parasitic plants

“…Triphysaria is a genus of five hemiparasitic species that grow as common annuals throughout the Pacific Coast of the western USA (Hickman, 1993). Triphysaria has a broad host range that includes maize, rice and Arabidopsis, and although Triphysaria is closely related to the agricultural pests Striga and Orobanche, Triphysaria has no agricultural significance and so can be grown without quarantine restrictions (Goldwasser et al, 2002). Triphysaria flowers are amenable to classical genetic manipulations and genomic resources are being developed, making Triphysaria a useful model species for parasite studies (Torres et al, 2005).…”