The Molecular Mechanisms Of Stimulated The Thermotolerance And Reproduction Of The Brown Planthopper Induced By Jinggangmycin

Biological disaster or biological extinction caused by global warming and climate change is one of the focus issues of global concern.Of which agricultural pest outbreaks is closely related to food safety of a half of world population.However,if extrinsic factors(e.g.agricultural antibiotics)enhance their thermotolerance and reproduction,populations outbreaks inevitably occur,which will result in severe consequences including increased crop losses and decreased food security at the global level.The brown planthopper(BPH)Nilaparvata lugens Stal(Hemiptera:Delphacidae)is a serious pest of rice crops in temperate and tropical regions of Asia.BPH outbreaks in tropical and sub-tropical Asia in recent are considered to be associated with excess use of pesticides and climate change.We posed the hypothesis that the range expansion is due to a syndrome of adaptations to the continuous presence of agricultural chemicals(insecticides and a fungicide)over the last 40 years.The adaptive syndrome is multi-faceted,including highly increased insecticide resistance,increased fight capacity,increased reproduction and population sizes and,as shown here,enhanced thermolerance.The possibility that exposure to agricultural chemicals can led to increased reproduction and thermotolerance in some insect pests,under the current trend of global warming,is a recent and particular worry.This study tested whether exposure to jinggangmycin(JGM),an agricultural antibiotic widely used in Asian rice production,enhances thermotolerance and reproduction of BPH.1.Influence of JGM on the reproduction and thermotolerance of Hsp70-silenced BPHTo evaluate effects of Hsp70 silencing on reproduction and thermotolerance of JGM-treated female BPH,feeding-based RNAi artificial diet contained dsHsp70 was adopted.Results demonstrated that the number of eggs laid,preoviposition period and oviposition period of dsHsp70-treated females did not differ from that of controls at 26?.While at 34? upon dsHsp70 treatment,the number of eggs laid and oviposition period were substantially reduced in comparison with controls,down by 74.1%and 37%,respectively,meanwhile the preoviposition period was increased by 55.2%.When the temperature was elevated to 40?,Hsp70 silencing significantly led to higher rate of mortality than controls and the relative expression of Hsp70 peaked at 2 hour-point post-treatment,then gradually declined over time.Besides,the median lethal time(LTso)was decreased by 39.3%for BPH feeding dsHsp70 diet.2.Influence of JGM on the reproduction and thermotolerance of Acc-silenced BPHThe RNAi targeting Acc was conducted following the same procedure as Hsp70.Results indicated that the number of eggs laid and oviposition period of dsAcc-treated females remarkably decreased by 69.8%and 26.3%along with preoviposition period up by 75.8%compared to controls at 26?.While at 34? upon dsAcc treatment,the number of eggs laid and oviposition period were substantially reduced in comparison with controls,down by 77.7%and 35.4%,respectively,meanwhile the preoviposition period was delayed by 58.6%.In contrast to Hsp70,no significant differences on the median lethal time(LT50)and mortality rate between Acc-silenced treatments and control.