Pathogenicity of Isaria fumosorosea to Bemisia tabaci , with some observations on the fungal infection process and host immune response

摘要: Isaria fumosorosea is an important pathogen of whiteflies, and used as a mycoinsecticide against this pest in many regions the world. We quantified pathogenicity Chinese isolate IF-1106 different life stages sweetpotato whitefly, Bemisia tabaci, on cucumber plants, describe infection process aspects host immunological response laboratory. The second instar was most susceptible stage to infection, with mortality rates at 10(7)conidia/ml ≈83% after 7d. Scanning electron microscopy monitor morphological process. following were observed; conidia adhered cuticle B. tabaci began germinate within 6h inoculation, appressoria development 24h, germ tube penetration 48h, emergent hyphae 72h, secondary conidiogenesis 96h mass hyphal proliferation occurring cadavers 120h. activities endogenous enzymes evaluated from homogenate various intervals post infection. Three associated antioxidant activity [superoxide dismutase (SOD), perioxidase (POD), catalase (CAT)], two detoxification [glutathione S-transferase (GSTs) carboxylesterase (CarE)] apparently upregulated instars infected by I. fumosorosea. Enzyme reached peak values 48-60h then decreased significantly lower than controls 84h mycosis occurred. Our results provide new insights into potential physiological fungal isolate.