摘要
Acyl-coenzyme A （Acyl-CoA） desaturases play a key role in the biosynthesis of female moth sex pheromones. Desaturase genes are encoded by a large multigene family, and they have been divided into five subgroups on the basis of biochemical functionality and phylogenetic affinity. In this study both copy numbers and transcriptional levels of desaturase genes in the European corn borer （ECB）, Ostrinia nubilalis, were investigated. The results from genome-wide screening of ECB bacterial artificial chromosome （BAC） library indicated there are many copies of some desaturase genes in the genome. An open reading frame （ORF） has been isolated for the novel desaturase gene ECB ezi-A11~ from ECB gland complementary DNA and its functionality has been analyzed by two yeast expression systems. No functional activities have been detected for it. The expression levels of the four desaturase genes both in the pheromone gland and fat body of ECB and Asian corn borer （ACB）, O. furnacalis, were determined by real-time polymerase chain reaction. In the ECB gland, All is the most abundant, although the amount of A14 is also considerable. In the ACB gland, A14 is the most abundant and is 100 times more abundant than all the other three combined. The results from the analysis of evolution of desaturase gene transcription in the ECB, ACB and other moths indicate that the pattern of A 11 gene transcription is significantly different from the transcriptional patterns of other desaturase genes and this difference is tied to the underlying nucleotide composition bias of the genome.
Acyl-coenzyme A （Acyl-CoA） desaturases play a key role in the biosynthesis of female moth sex pheromones. Desaturase genes are encoded by a large multigene family, and they have been divided into five subgroups on the basis of biochemical functionality and phylogenetic affinity. In this study both copy numbers and transcriptional levels of desaturase genes in the European corn borer （ECB）, Ostrinia nubilalis, were investigated. The results from genome-wide screening of ECB bacterial artificial chromosome （BAC） library indicated there are many copies of some desaturase genes in the genome. An open reading frame （ORF） has been isolated for the novel desaturase gene ECB ezi-A11~ from ECB gland complementary DNA and its functionality has been analyzed by two yeast expression systems. No functional activities have been detected for it. The expression levels of the four desaturase genes both in the pheromone gland and fat body of ECB and Asian corn borer （ACB）, O. furnacalis, were determined by real-time polymerase chain reaction. In the ECB gland, All is the most abundant, although the amount of A14 is also considerable. In the ACB gland, A14 is the most abundant and is 100 times more abundant than all the other three combined. The results from the analysis of evolution of desaturase gene transcription in the ECB, ACB and other moths indicate that the pattern of A 11 gene transcription is significantly different from the transcriptional patterns of other desaturase genes and this difference is tied to the underlying nucleotide composition bias of the genome.
