Domestication for imidacloprid-resistant strain of rice brown planthopper, Nilaparvata lugens St?l, symbiote, Candida lipolytica

Abstract:

To further study physiological-biochemical mechanism of symbiote in imidacloprid-resistant brown planthopper (Nilaparvata lugens), imidacloprid-resistant strain of symbiote, Candida lipolytica, was domesticated with different concentrations of imidacloprid based on effect of insecticides on growth and development of C. lipolytica. The results indicated that after in vitro C. lipolytica, on solid culture medium containing 2 000, 1 000 and 500 mg/L imidacloprid were subcultured for continuous 20 generations, the colony numbers of C. lipolytica on solid culture medium containing 2 000 mg/L imidacloprid were no significant difference with those on control medium containing non-imidacloprid. When numbers of colony kept stable for continuous three generations, the domesticated strain was called 2 000 mg/L imidacloprid- resistant one. Morphological changes of imidacloprid -resistant and -susceptible strains pseudohyphae were further observed using light microscope, it was found that pseudohyphae of imidacloprid- resistant strain occurred malformation and become shorter, some appeared enlargement.