GALL DEVELOPMENT IN HAIRY ROOT CULTURES INFECTED WITH PLASMODIOPHORA-BRASSICAE

The development of galls in hairy root cultures of Brassica napus inoc ulated with Plasmodiophora brassicae is reported for the first time. R oot hair infection and the development of secondary zoospores were not observed, primary zoospores being able directly to initiate cortical root infection. Galls developed by cell division within the root stele while cortical cells became plasmolysed and collapsed. Starch grains accumulated in infected cells. The potential use of hairy root culture s for study of the biology of P. brassicae is discussed.