Identification of an in planta-induced mRNA of Plasmodiophora brassicae

RNA fingerprinting using the arbitrarily primed polymerase chain reaction (RAP) were performed with a host-pathogen system consisting of a Chinese cabbage cultivar and two isolates of Plasmodiophora brassicae. One of the RAP products expressed specifically in a susceptible response (clubroots) was isolated, cloned, and sequenced. Northern blot analysis confirmed that the product (Y10) was expressed in clubroot tissue where P. brassicae was shown to be at a vegetative growth stage. Southern blot analysis suggested that the Y10 sequence existed as a single-copy per haploid genome of P. brassicae. Thus, Y10 sequence appears to be a transcript from P. brassicae growing in planta.