One of the key enzymes involved in moth phermone biosynthesis, palmitoyl coenzyme A Delta-11 desaturase, has been characterized in subcellular fractions from pheromonal glands of adult female Spodoptera littoralis. Desaturase activity was dependent on the presence of pyridine nucleotides with nicotinamide adenine dinucleotide phosphate (NADP) better electron donor than reduced NADP (NADPH). Incubation with free acids showed the highest activity for palmitic acid followed by myristic and stearic acids. (Z)-11-hexadecenoic acid (methyl ester) was the product of desaturase activity. The optimal pH for the enzyme was 6.8-7.2 at 25 C.
With the general aim to make insect semiochemicals more widely available for crop protection, the production of different insect sex pheromones by genetically engineered crop plants will be studied. Biosynthetic routes to Lepidopteran sex pheromones involved as crucial step dehydrogenation at specific sites of C18 and C16 aliphatic chains. In the present study the gene responsible for producing the -11 desaturase would be transferred to a crop plant to enable it to provide the source of Lepidopteran sex phermones with C16 carbon chains unsaturated at C11, such as those of several important pests, diamondback moth Pluttellaxylostel and Sesamia spp. enabling insect mating disruption.
Funding SchemeCSC - Cost-sharing contracts
AL5 2JQ Harpenden, Herts