Effects Of High-temperature Stress On Resistance Of Bemisia Tabaci Q To Insecticides And Mechanism

Global warming has a profound impact on insect, including geographical distribution, growth speed, host plant range, endosymbiont abundance, population density and so on, leading to some pests frequently occurred. Recent studies found that high temperature environment influenced insecticide resistance in insects. Bemisia tabaci (Gennadius) is thermotolerance insects.Temperature has a great influence on the outbreak of whitefly. B. tabaci have high resistance to many kinds of insecticides, especially neonicotinoid insecticides. So, based on the achievement in the past, we assume that high temperature also has a certain influence on resistance of whiteflies.To reveal effects of high-temperature stress on resistance of B. tabaci Q and its mechanism. We conducted that:Change in insecticide resistan of B. tabaci Q after high temperature 31? and 35? pretreatments was studied; Expression level of detoxifying enzyme genes associated with insecticide resistance and activities of detoxifying enzymes were measured, in order to reveal the mechanism that high-temperature stress effect resistance of B. tabaci Q to insecticides. The results included:1. High temperature 31? enhanced the insecticide resistance of whiteflies, however, high temperature 35? reduced the insecticide resistance of whiteflies. The result of 31? pretreatment was that mortalities of 48 hours were all less than mortality in control (64.12%). The result of 35? pretreatment was that mortalities of 48 hours were all more than mortality in control (64.12%).2. P450 genes were involved in the effects of high-temperature stress on resistance of B. tabaci Q, namely up-reguLation in 31?, down-reguLation in 35?. CarE and GSTs genes maybe involved in the process. The result of 31? pretreatment was that the expression levels of CYP6CM1 and CYP6LIKE1 were significantly higher than control whiteflies (P<0.05); the expression levels of CarEl was significantly higher than control whiteflies (P<0.05), the expression levels of CarE2 was significantly higher than control whiteflies were higher than control whiteflies (P<0.05) or no significantly changes; the expression levels of GST1 were almost higher than control whiteflies (P<0.05). The result of 35? pretreatment was that the expression levels of CYP6CM1, CYP6V5, CTP6LIKE1, and CYP6DZ7 were significantly lower than control whiteflies (P<0.05), the expression levels of CYP6a8 were almost significantly lower than control whiteflies (P<0.05); the expression levels of CarE2 were no significantly changes; the expression levels of GST2 and GST3 were lower than control whiteflies (P<0.05) or no significantly changes.3. P450 mediated detoxification metabolism in B. tabaci Q lead to variation of insecticide resistance. CarE and GSTs may be involved in the process. The activities of P450 in whiteflies pretreated with 31? showed a trend that increased and then reduced to the activity of control. However, that in whiteflies pretreated with 35? showed a reduced trend. The activities of CarE in whiteflies pretreated with 31? and 35? were all higher than that in control, but the enhanced activity were more obvious in 31? than that in 35?. The activities of GSTs in whiteflies pretreated with 31? showed an increased trend, while the activities of GSTs in whiteflies pretreated with 35? showed a reduced trend as a whole.In conclusion, high temperature 31? enhanced resistance of B. tabaci Q to thiamethoxam,35? lowered resistance of B. tabaci Q to thiamethoxam. P450s were involved in the metabolism resistance, CarE and GSTs maybe involved in the process...