The Epigenetic Regulation Mechanism Of Temperature Adaptation In Bemisia Tabaci Invasive Species

Insect geographical distribution and dispersion is due in large part to the tolerance of insects to extreme temperature,especially for invasive insects.Whitefly,Bemisia tabaci,has adapted a great range of environments to invade into many areas of the world.Precise knowledge of temperature-dependence of B.tabaci is necessary for us to understand its population dynamics under current and future climate change scenarios.Since several key factors involved in epigenetic regulation have been identified and verified during stress progress in B.tabaci,epigenetic mechanisms of adaptation must exist.However,very little is known about epigenetic mechanisms regulating temperature tolerance.This study takes B.tabaci invasive species as the research object,using RNA-seq,small RNA-seq,ATAC-seq,fluorescent quantitative PCR,RNAi feeding,to conduct the study about epigenetic regulation mechanism of temperature adaptability of B.tabaci invasive species.The purpose of the study is to explore the role of gene regulated by non-coding RNA and chromatin accessibility in epigenetic regulation mechanism of temperature adaptation.The main results and conclusions are as follows:1.Epigenetic regulation:non-coding RNA and temperature adaptation（1）The results show that the gene expression level of non-coding RNA changes with the change of temperature stress by detecting the expression dynamics of non-coding RNA at the transcription level under different temperature and pressure.（2）Then we predicted the target genes regulated by non-coding RNA,detected the changes of expression level of target genes under different temperature stress,verified the regulatory relationship between non-coding RNA and their target genes and verified the function related to temperature tolerance of non-coding RNA and their target genes.These results find that non-coding RNA participate in the temperature adaptation process in B.tabaci invasive species by regulating the expression level of target genes.In this section of the study,it is mainly verified that two non-coding RNAs（miRNA-998 and novel₁29）are involved in the process of B.tabaci response to temperature stress.Novel₁29 is a more critical non-coding RNA,which regulates BtRGS7 to participate in the process of low temperature adaptation,and regulates BtMGAT3 to participate in the process of high temperature tolerance.2.Epigenetic regulation:chromatin accessibility and temperature adaptation（1）The results show that the chromatin accessibility of B.tabaci invasive species changes with the change of temperature stress by detecting the dynamic changes of chromatin accessibility under different temperature stress.The results preliminarily confirmed that there is a certain correlation between chromatin accessibility and temperature adaptation.（2）By searching for genes corresponding to chromatin regions where chromatin accessibility has changed due to temperature stress and detecting their transcriptional expression level changes under different temperature stress,it was found that the transcriptional expression level of some genes has changed accordingly.It is preliminarily confirmed that the change of chromatin accessibility can lead to the change of gene transcriptional expression level,and this regulation method is directly related to the temperature adaptation process in B.tabaci invasive species.After interfering with the expression of some of the above target genes（BtP450 4C1 and BtCar3）,the high temperature tolerance of B.tabaci was significantly reduced.The results further confirmed that the change in the transcriptional expression level of genes regulated by chromatin accessibility not only exist in the process of temperature adaptation of B.tabaci,but play an important role.（3）Subsequent we conduct the functional enrichment analysis of differential genes at the transcription level caused by changes in chromatin accessibility.The results showed that in the process of chromatin accessibility involved in the regulation of temperature tolerance,the main pathway response to low temperature pressure is enzyme activity,and the main pathway cope with high temperature pressure is the synthesis and metabolism of organic substances.In summary,epigenetic regulation plays a key role in the temperature adaptation process in B.tabaci.This study reveals a role of miRNAs in insect temperature adaptability,an important determinant of ecological distributions,which provides a new avenue for the study miRNAs regulation for gene expression in insects and controlling the invasion and harm of B.tabaci.Otherwise,our study provides a dynamics framework for exploring the relationship between transcriptome and accessible chromatin under different temperature stress and a new avenue to unravel the transcriptional regulatory mechanisms that facilitate the occurrencce of relevant molecular events.