Molecular Identification Of Helicovepa Armigera Acyl-CoA Delta-9 Desaturase Gene

Acyl-Co A delta-9 desaturase, one of the fatty acid desaturase, is combining with endoplasmic reticulum membrane of animals and fungi.It plays important roles in pheromone biosynthetic of insect and the regulation of cell membrane fluidity.In this experiment,the characterizations of acyl-Co A delta-9 desaturase gene from Helicovepa armigera were studied and these studies further provide foundation to explore the function of acyl-Co A delta-9 desaturase in fatty acid metabolism of inscet.The main results are as follows:(1) Acyl-Co A delta-9 desaturase gene from Helicovepa armigera was obtained by using reverse transcription polymerase chain reaction(RT-PCR) and rapid amplification of c DNA ends(RACE). Nucleotide sequence analysis revealed that the gene is 2931 bp in size of genomic DNA containing a 1062 bp coding region encoding a 353-amino acids(aa).Gen Bank accession number GU393246. Ex PAsy analysis display that the isoelectric point of the encoded protein is 8.66 and the molecular weight is 40.66 k Da.Homology analysis showed that predicted amino acid sequence of acyl-Co A delta-9 desaturase from Helicovepa armigera share more than 80% identity with other insects. The phylogenetic analysis suggests that acyl-Co A delta-9 desaturase gene is high-degree conservation during the evolution.(2) The developmental transcription level of acyl-Co A delta-9 desaturase gene was studied by using Real-time PCR.The results showed that transcription level of the gene reached expression peak in 5th—72h instar larvae,and is more higher from 5th—24h instar larvae to 5th—72h instar larvae, compared with that in 4th—12h, 4th—36h, 5th—12h,from 5th—96h to 2d pupa.In addition,the transcription level of the gene is on a rise with the larva’s growth from 4th instar larvae to 5th — 72 h instar larvae.Besides its transcript increased in feeding stages with the growth and decrease in the 4th and 5th instar ecdysis stage,which consist with the change of 20 E titre.Therefore, it has been proposed that thetranscription level of the gene is related to hormonal regulation.(3) Acyl-Co A delta-9 desaturase gene expression analysis was studied after starvation treatment by using Real-time PCR. The results showed that the adverse factor strongly induce the gene expression.(4) The acyl-Co A delta-9 desaturase gene expression analysis in 5th instar larvae after hormone treatment was studied by using Real-time PCR. The results showed that methoprene(JH analog) had a obviously inhibitory effect.But 20 E significantly induce acyl-Co A delta-9 desaturase gene expression, which arrive highest expression after12h-20 E treatment.Key words:...