Bioinformatics Analysis Of Alternanthera Philoxeroides Terpene Synthase Gene And Cloning Of Its Nerolidol Synthase Gene

Volatile tetrpenoids in plants can affect the host selection behavior of insects,in which the main factors that identify the host plants are the difference in the quality and quantity of certain volatiles.Agasicles hygrophila is a swarm of natural enemies of invasive plant Alternanthera philoxeroides.Previous studies have shown that the terpene DMNT from Alternanthera philoxero des plays a key role in Agasicles hygrophila identification.In order to further explore the molecular mechanism of its action,this paper mainly studied the terpene synthase genes and the nerolidol synthase gene,the key enzyme which produced DMNT.1.A total of 9.91 Gb reads were obtained by RNA-seq technique using the illumina hiseq2500TM platform for Alternanthera philoxeroides transcriptome sequencing.And after assembly splicing,received a total of 182318 Transcripts and 83179 Unigenes.After homologous comparison with NR,Swiss-Prot,GO,COG,KOG and KEGG protein databases,63536 Unigene with annotated information was obtained,and the Unigene database was constructed and the sequencing results were good.2.Screening out the 32 terpene synthase genes of Alternanthera philoxeroides,these genes are highly homologous to Beta vulgaris terpene synthase genes.Based on the family classification criteria of terpenoid synthetic genes,seven sequences of intact open reading frames were analyzed by phylogenetic analysis.ApTPS9,ApTPS 17,ApTPS 18 and ApTPS21 were divided into TPS-a family;and ApTPS5 was divided into TPS-b family,ApTPS23 into the TPS-e family;ApTPS19 into the TPS-g family.3.The results showed that the expression of nerolidol synthase genes were studied at different time after mechanical injury and insect feeding.The nerolidol synthase genes showed high expression immediately after being damaged,with immediate defense.The expression of ApTPS 19 gene was significantly higher than that of other treatments at 0 h after feeding,which was 12.41 times of that of healthy plants,and which was 4.36 times of mechanical injured plants the same time.4.The nerolidol synthase gene ApTPS 19 was cloned,and the sequence of 1951 bp was obtained.This gene had a typical aspartic acid enriched motif DDXXD domain and was a typical terpene synthase gene.The gene was predicted by subcellular localization,and it was found that the gene was mainly located in the cytoplasm and was a typical monoterpene synthase.The overexpression vector with ApTPS 19 sequence was constructed and the wild type Arabidopsis thaliana was transformed to provide a basis for the validation of subsequent insect behavioral experiments,which laid the foundation for the further explanation of the molecular mechanism of the specific relationship between Alternanthera philoxeroides and Agasicles hygrophila.