| Bemisia tabaci(Gennadius)is a major pest of agricultural crops worldwide.It can cause serious damages to hundreds of crops,resulting huge economic losses.With increasing reports of insecticide resistance development in B.tabaci,integrated pest management(IPM)with biological control as a key role is becoming more and more popular with every passing day.Encarsia formosa Gahan and Eretmocerus hayati Zolnerowich & Rose are important parasitoids of B.tabaci having high parasitic potential as well as prospects of field application.Life history,survival,reproduction,distribution of insects can be affected by temperature.Insects also respond to adverse temperatures,in which differential gene expressions plays the most fundamental role.The effects of different temperature regimes on biological characteristics of B.tabaci and its parasitoids(En.formosa and En.hayati),were observed during these study.Furthermore,variations in transcriptome sequences of B.tabaci and its parasitoids(En.formosa and Er.hayati)were also studied as a function of temperature change.The expressions of heat shock-related genes at high and low temperatures were determined.The main results are as follows.(1)Effects of different temperature regimes on biological characteristics of B.tabaci and its parasitoids(En.formosa and Er.hayati)were analyzed.The development periods of B.tabaci and Er.hayati shortened at first and then prolonged with increasing temperature,while that of En.formosa continuously shortened with increase in temperature.Low temperature had the greatest effect on the development duration of Er.hayati,while high temperature had the greatest effect on En.formosa and the smallest effect on B.tabaci.The survival rates of the three insects were all the lowest at 35℃.There was no significant difference of the survival rates of En.formosa between 20℃ to 29℃ and the survival rates of Er.hayati between 20℃ to 32℃ respectively.The highest survival rate of B.tabaci was at 26℃.Er.hayati was the least affected by temperature on survival rate,while that of En.formosa was the most affected by high temperature of 32℃ and 35℃.The longevity of female adults of the three insects decreased with the increase of temperature.But there was no significant difference between 23℃ and 26℃ of En.formosa,26℃ and 29℃ of Er.hayati.Temperature rise had the greatest effects on longevity of En.formosa,while had the smallest effects on Er.hayati.The weights of the three insects were all the heaviest at 20℃.High temperature had the greatest effect on weight of B.tabaci.(2)Transcriptome analysis of B.tabaci revealed,371 up-regulated DEGs and 210down-regulated DEGs in 20℃ Vs 26℃,860 up-regulated DEGs and 277 down-regulated DEGs in 32℃ Vs 26℃,713 up-regulated DEGs and 415 down-regulated DEGs in 32℃ Vs20℃.For En.fomorsa,55 DEGs were up-regulated and 39 DEGs were down-regulated in20℃ Vs 26℃.277 up-expressed DEGs and 402 down-expressed DEGs were observed in comparison of 32 ℃ and 26℃ treatments.Whereas 605 DEGs were up-regulated and 464 DEGs were down-regulated in 32 ℃ Vs 20℃.Transcriptome analysis of Er.Hayati revealed,89 up-regulated DEGs and 244 down-regulated DEGs in comparison of 20℃ and26 ℃ treatments,43 up-regulated DEGs and 56 down-regulated DEGs in comparison of 32℃and 26℃ treatments,1460 up-expressed DEGs and 1238 down-expressed DEGs in comparison of 32 ℃ and 20℃ treatments.DEGs annotation to GO function database revealed that majority of the DEGs from the three insects were annotated to GO function terms cellular process,metabolic process,single-organism,cell,cell part,membrane,membrane part,organelle,binding,catalytic activity,and so on.Further annotation of DEGs to KEGG pathways showed the involvement of DEGs in many pathways,but the pathways and the DEGs numbers were not the same for different insects.(3)Differentially expressed heat shock-related genes were screened out from DEGs of B.tabaci,En.formosa and Er.hayati.Four HSP70 and three HSP68 genes were obtained from B.tabaci DEGs.Four HSP70 and two HSP68 genes were up-expressed at 32℃compared with 26℃ treatment,and only one HSP70 was down-expressed at 20℃compared with 26℃.One HSF,HSC70,HSP70 and HSP83 were obtained from En.formosa DEGs.HSF was up-expressed,and HSC70 and HSP70 were down-expressed at 32℃compared with 26℃,and no DEGs were found at 20℃ compared with 26℃.Two HSP83,one HSP68 and one HSP10 were obtained from Er.hayati DEGs.HSP68 was up-expressed at 32℃ compared with 26℃.There was no differentially expressed heat shock-related genes found in comparison of 20℃ and 26℃.The insects were subjected to 40℃ and 8℃ stress to analyze the effects of short-term temperature stress on the genes.Compared with 26℃,for B.tabaci,five HSPs up-expressed largely and one HSP down-expressed significantly after being stressed at40℃,while the expression of each HSPs did not change significantly after being stressed at8℃.For En.formosa,HSC70 and HSP83 were up-expressed and HSP70 was down-expressed at 40℃,and HSP70 was down-expressed after stressed at 8℃.For Er.Hayati,HSP68 was significantly up-expressed at 40℃ stress and HSP10 and 2 HSP83 genes were up-expressed at 8℃ stress.(4)Activity levels of CAT and SOD of the three insects at 20℃,26℃ and 32℃ were abtained.Activity levels of CAT and SOD of B.tabaci,En.formosa and Er.hayati were all increased significantly at 32℃.At 20℃,activity level of CAT of B.tabaci was decreased while that of En.formosa and Er.hayati were increased,activity levels of SOD of B.tabaci and En.formosa were decreased while that of Er.hayati was increased. |
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