Transfer of benomyl-resistance by hyphal fusion of Botrytis cinerea.

The present investigation was conducted to authenticate whether a benomyl-sensitive strain of Botrytis cinerea acquired the benomyl-resistance by hyphal fusion with the resistant strain. In two experiments on hyphal fusion between IPCR-1 (the sensitive strain) and IHES-3 (the resistant strain), eight resistant strains were obtained from the fusion of mycelium (PHGF-1) or single hyphae (PHDF-28) of IPCR-1 with IHES-3. MIC of benomyl for PHGF-1 was 3, 500 ppm, which was higher than that for IHES-3. It also surpassed IPCR-1 and IHES-3 strains in growth and pathogenicity. MIC of benomyl for PHDF-28 ranged from 2, 050 to 2, 250 ppm, which was lower than that of IHES-3. They were variable in growth and pathogenicity. PHGF-1 and PHDF-28 were stable in their acquired properties, even though the subculture was repeated more than ten times of PSA media.