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Ecology and Epidemiology

Infection by Polymyxa betae and Plasmodiophora brassicae of Roots Containing Root-Inducing Transferred DNA of Agrobacterium rhizogenes. J. Mugnier, Rhône-Poulenc Agrochimie, 69263 Lyon Cedex 09, France; Phytopathology 77:539-542. Accepted for publication 18 July 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-539.

Typical infections of Polymyxa betae and Plasmodiophora brassicae develop in root organ culture of their host, Beta vulgaris or brassicas, containing the root-inducing transferred DNA of Agrobacterium rhizogenes. In dual culture, the fungal life cycles consisted of two distinct phases. One occurred in the epidermis of the susceptible host, characterized by the production of primary encysted plasmodia, and the other occurred in the root cortical tissue characterized by the production of cystosori. The principal growth phases are the fragmentation and segmentation of the primary plasmodia and of the cystogenous plasmodia.