Dry Powder and Extract of Posidonia australis Hook. F., a species of Seagrass, Stimulate the Germination of the Pathogen Plasmodiophora brassicae and Control Clubroot of Chinese Cabbage

Stimulation by Caffeic Acid, Coumalic Acid, and Corilagin of the Germination of Resting Spores of the Clubroot PathogenPlasmodiophora brassicae

“…F.) stimulate the germination of resting spores, and suppress the formation of clubroots in Chinese cabbage; for example, infected soil can be treated with 5z (w W w) dry Posidonia powder 7 days before planting. 8) These results suggest that GSF exist not only in crucifers but also in other kinds of plants. In this study, we examined the eŠects of some chemicals commonly found in plants on the germination of P. brassicae resting spores.…”

“…8) Here, the infection rate of root hairs in 1 day of incubation of resting spores with 1 mM caŠeic acid was higher than the control without treatment, but the rates with 10 days of incubation were lower than in the control. These results suggested that the timing of treatment of infected soil or incubation of the resting spores with GSFs is important for prevention of infection by the clubroot pathogen.…”

“…8) Suzuki et al also reported that the extract of crucifers contained a GSF, which is adsorbed by XAD-4. 7) Thus, the GSF seems to be ubiquitous in some plants.…”

“…Therefore, in this study, we examined the eŠects of caŠeic acid on the germination of P. brassicae resting spores. Because the GSF may be adsorbed on to the artiˆcial resins such as HP20 or XAD4, 7,8) other chemicals having such characteristics also were examined.…”

“…One hundred spores were counted three times under UV excitation with a ‰uorescent microscope. The stage of germination was evaluated as described by Hata et al 8) Stages were 0 for the presence of a developed cell wall, 1 for the presence of both a cell wall and germination cave, 2 for the disappearance of the cell wall and clear development of a germination cave, and 3 for the disappearance of both the cell wall and germination cave, and the appearance of dark red pigment. The experiment was replicatedˆve times.…”