Plasmodiophora brassicae wani nau'in protist ne wanda ke haifar da cutar da ake kira clubroot a cikin tsire-tsire, musamman a cikin dangin Brassicaceae, kamar kabeji, broccoli, farin kabeji, da radish. Sunan "Plasmodiophora" yana nufin plasmodium, wani nau'i na multinucleate, amoeboid cell wanda ke da halayyar wannan rukuni na kwayoyin halitta. "Brassicae" yana nufin gaskiyar cewa kwayoyin halitta suna da alaƙa da tsire-tsire a cikin jinsin Brassica.