Suppression of pheromone biosynthesis and mating behavior by RNA interference of pheromone gland-specific fatty acyl reductase in Maruca vitrata

In moths,various enzymes,such as fatty acid synthases,fatty acyl desaturases,and fatty acyl reductases(FARs),are involved in pheromone biosynthesis.In particular,pheromone gland-specific FAR(pgFAR)plays an important role in converting the functional group from carboxylic to alcohol during pheromone biosynthesis.A novel pgFAR of Maruca vitrata,Mvi-pgFAR,was identified through transcriptome sequencing of its pheromone gland.To investigate the involvement of Mvi-pgFAR in pheromone biosynthesis,Mvi-pgFAR was cloned from the pheromone gland and suppressed by RNA interference(RNAi).Mvi-pgFAR harbored several conserved motifs related to NAD(P)H-binding,N-glycosylation,and adenosine/guanosine triphosphate binding.Phylogenetic analysis revealed that Mvi-pgFAR with other lepidopteran pgFARs formed an independent clade.Mvi-pgFAR was specifically expressed only in the pheromone gland.Quantitative real-time polymerase chain reaction showed that the diurnal expression levels of Mvi-pgFAR in the pheromone gland were the highest at 2 h before the scotophase.After primarily confirming Mvi-pgFAR suppression by RNAi,(E,E)-10,12-hexadecadienal(E10E12-16:Ald),a major sex pheromone component,was quantified by gas chromatography.When Mvi-pgFAR was successfully suppressed,E10E12-16:Ald production was reduced by up to half of that of the control,and the mating rate was subsequently decreased.Our results demonstrate that Mvi-pgFAR downregulation can suppress mating behavior by changing the relative sex pheromone component ratio,suggesting that Mvi-pgFAR can be used as a novel control target.