Cabbage looper moth, pheromone components

Fig.i General biosynthetic pathways for the production of alcohol, aldehyde, and acetate ester pheromone components in female moths. Top production of saturated fatty acids. Middle production of monounsaturated fatty acids and limited chain shortening produces intermediate compounds that can be reduced to an alcohol. Aldehyde and acetate ester pheromones are produced by an oxidase and acetyl-transferase, respectively. Bottom biosynthetic pathway for the production of the acetate ester pheromone components in the cabbage looper moth, Trichoplusia ni. The CoA derivatives are reduced and acetylated to form the acetate esters. Additional pheromone components include 12 OAc and ll-12 OAc... 

In contrast to pheromones that involve single complex compounds, many moth species have been found to utilize a specific blend of relatively simple fatty acid-derived compounds. It appears that the evolution of a unique enzyme, A1 desaturase, used in combination with 2-carbon chain-shortening reactions (Figure 3) has allowed moth species to produce a variety of unsaturated acetates, aldehydes, and alcohols that can be combined in almost unlimited blends to impart species specificity. For example, biosynthetic precursors for the six-component pheromone blend of acetates for the cabbage looper moth (12) (Figure 2) can be determined easily from the cascade of acyl intermediates produced by the A11-desaturase and chain-shortening reactions (Figure 3). 

Sex pheromone component ratio in the cabbage looper moth altered by a mutation affecting the fatty acid chain-shortening reactions in the pheromone biosynthetic pathway. Insect Biochemistry and Molecular Biology 24 373-381. 

Jurenka R. A., Haynes K. F., Adlof R. O., Bengtsson M. and Roelofs W. L. (1994) Sex pheromone component ratio in the cabbage looper moth altered by a mutation affecting the fatty acid chain-shortening reactions in the pheromone bisoynthetic pathway. Insect Biochem. Molec. Biol. 24, 373-381. 

The importance of elucidation of pathways of biosynthesis which regulate pheromone production is exemplified by the identification of additional pheromone components for the cabbage looper moth. 

Bjostad and Roelofs (1983) were the first to determine correctly how the major pheromone component for a particular moth was biosynthesized. This was done by looking for possible fatty acid intermediates and by monitoring the incorporation of radiolabeled precursors into pheromone components. They showed that glands of the cabbage looper, Trichoplusia ni, utilize acetate to produce the common fatty acids octadecanoate and hexadecanoate which undergo All desaturation to produce Zll-18 acid and Zll-16 acid. But the main pheromone component was Z7-12 OAc, which presumably was made from Z7-12 acid. To demonstrate how the fatty acid precursor Z7-12 acid was produced, [3H-16]-Z1 l-16 acid was applied to glands and monitored for incorporation. It was incorporated into both Z7-... 

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