| Aleurolyphus ovatus Troupeau,belonging to Arachnida,Astigmata,Acaridae,Aleurolyphus,is one of the most predominant species of Acaridae in the world.In recent years,the stored grain and diet had been reported to exceed the standard of heavy metals.Lead(Pb)is one of the most serious and widespread heavy metals,which can enter the body through different ways such as breathing,feeding and epidermis,caused harm to the organism.However,molecular mechanism has not yet been reported in Acari.In this study,A.ovatus were fed on artificial diets with low lead concentration lead(12.5mg/kg)and high lead concentration lead(100 mg/kg).The transcriptome of A.ovatus was sequencing using Illumina technology,and gene expression profiles and metabolic pathway at different concentrations of lead stress were analyzed.The study on the detoxification and immune system can provide theoretical basis and practice guidance to response mechanism of heavy metal lead stress of A.ovatus.At the same time,it can serve a reference for future study of gene function,protein and metabolites.The main results are as follows:1.The transcriptome of A.ovatus obtained about 30.6 G,GC content was about50%,Q20 was about 97%,which indicated that the sequence quality was higher.44,362Unigenes with a total length of 6.9?10~7 bp and an average length of 1,547 bp was assembled by Trinity.996 unigenes were successfully annotated in the database by seven functional database annotations(NR,NT,GO,KOG,KEGG,SwissPprot,and InterPro),while 17,967(0.5%)unigenes were not annotated.Based on KO database,1262 genes were annotated and participated in 325 KEGG metabolic pathways.The Mn-SOD gene and the Cn/Zn-SOD gene were related in the longevity-regulating and peroxisomal pathways.Vitellogenin gene was annotated to the proteasome pathway in the folding,sorting,and degrading branches of genetic information processing.2.The expression of differential genes of A.ovatus were compared under different lead concentrations.Between L(low concentration)and H(high concentration),11,690unigenes were differently expressed,among them,4,892 genes were up-regulated and6,798 genes were down-regulated.Between N(control group)and H,5,689 unigenes were differentially expressed,among them,3,928 genes were up-regulated and 1,761genes were down-regulated.Between N and L,1,890 unigenes were differentially expressed,among them,310 genes were up-regulated and 1,580 genes were down-regulated.The number of L-H different genes is about 6 times that of N-L.Up-regulated genes and down-regulated genes were mainly related to proteins,such as those encoding virulence array proteins.In the pathway,the detoxification enzyme gene was expressed.For example,GST related to metabolism of xenobiotics by cytochrome P450,glutathione metabolism and drug metabolism-cytochrome P450.GST gene and CYP were down-regulated under lead stress.3.In order to verify gene annotation,10 gene sequences were choosed and sequenced.Their nucleotide sequences were compared with the sequences of transcriptome.The results showed that the similarity of two sequences was more than95%.In order to verify the expression of different genes,Vg was selected for qRT-PCR.The results showed the same tendency between qRT-PCR and the transcriptome for the expression of Vg,but the folds of expression were different.The expression level of low lead concentration was about 2.24 folds,the expression level of high lead concentration was about 1.00 folds,but in the transcriptome was 1.48,0.39 folds,respectively.In summary,this article analyzes transcriptome data of A.ovatus under different concentrations of lead stress and selects related genes,which provide a basis for exploring the molecular mechanisms that respond to heavy metal lead stress. |
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