Masahiko, Tamaki;Fumiyuki, Kobayashi;Keisuke, Suehiro;Shuichi, Ohsato;Michio, Sato

Nippon Vet & Life Sci Univ, Fac Appl Life Sci, Musashino, Tokyo 1808602, Japan;Meiji Univ, Sch Agr, Kawasaki, Kanagawa 2148571, Japan

appressorium formation;Blasin (R) Flowable;germination;Pyricularia oryzae;carbon dioxide microbubble

We investigated the possibility to reduce the usage of Blasie (R) Flowable (BF), a disinfectant inhibiting the germination and appressorium formation of Pyricularia oryzae Cavara conidia, by using carbon dioxide microbubbles (CO2MB). Germination was significantly inhibited by 10 000-fold diluted BF solution containing CO2MB generated by the decompression-type generator compared to CO2 millibubbles (CO2MMB) and CO2MB generated by the gas-water circulating-type generator. Appressorium formation in the 10000-fold diluted BF solution containing both CO(2)MBs was less than that in CO2MMB. Scanning electron microscopy showed wrinkles and dents on the surface of conidia treated with 5 000-fold diluted BF solution containing both CO(2)MBs. Via transmission electron microscopy, we observed the expansion of the vacuole and the intracellular space and bloated or absent lipid granules in the conidia treated with BF solution containing both CO(2)MBs. Our results show that inhibition of the conidium germination and appressorium formation of P oryzae Cavara by 10000-fold diluted BF solution could be achieved by using the decompression-type CO2MB.