東京都内青果市場での真菌汚染とチアベンダゾール抵抗性Penicillium digitatum の解析

The fungicides such as the thiabendazole (TBZ) are commonly used to prevent postharvest-disease on citrus, but the resistant fungi have been reported to appear by the continuous administration of these fungicides. The aim of this study was to know the fungal contamination and the distribution of TBZ resistant Penicillium digitatum in two vegetable and fruit markets in Tokyo. As the results of fungal contamination research, Penicillium spp. was isolated from all of 30 air samples of markets, and dominant fungi were P. digitatum (12/30) of subgenus Penicillium. The Penicillium spp. isolated from all 16 samples of citrus and 3 samples of towels were mainly on P. digitatum. Twenty-two isolates of P. digitatum were examined for their sensitivity to TBZ by disk diffusion method, and 16 of 22 isolates were resistant to TBZ. In addition, these TBZ resistant strains had a point mutation in the β-tubulin gene corresponding to amino acid mutation (F→Y) on codon position 200. The distribution of TBZ resistant isolates was estimated 70.4% in 27 isolates of P. digitatum including 5 of dead strains by the mutation (F200Y) analysis.