|Proveaux, Adron - RETIRED, ARS|
Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 2, 2005
Publication Date: February 1, 2006
Citation: Teal, P.E., Proveaux, A.T. 2006. Identification of methyl farnesoate from in vitro culture of the retrocerebral complex of adult females of the moth, Heliothis virescens (Lepidoptera: Noctuidae) and its conversion to juvenile hormone III. Archives of Insect Biochemistry and Physiology. 61:98-105 Interpretive Summary: Sexual maturity in female moths is regulated by juvenile hormone. For females to become sexually mature and ready to mate a specific level of this hormone must be produced. Juvenile hormone production is high during the larval stages but is reduced to negligible levels in pupae. For most moths production of juvenile hormone begins again just before the moth emerges as an adult. The fact that juvenile hormone regulates many aspects of moth physiology makes this hormone a key component for insect life. Scientists at the Center for Medical, Agricultural and Veterinary Entomology, USDA-ARS, Gainesville Florida have been studying how juvenile hormone is made by adult females of the tobacco budworm, a very important pest of cotton in the United States. They have discovered that juvenile hormone III, the major juvenile hormone produced by females is produced from methyl farnesoate. Previously, it had been thought that methyl farnesoate was not a precursor for this hormone in moths. This discovery clarified numerous questions regarding the production of juvenile hormone by moths and could lead the way to development of alternative methods for pest control based on inhibition of production of methyl farnesoate.
Technical Abstract: Gas chromatographic-mass spectral analysis of extracts obtained from in vitro culture of isolated retrocerebral complexes obtained from adult females of the moth Heliothis virescens resulted in identification of methyl farnesoate as well as, juvenile hormone III (JH III) but not JH III acid. Inhibition of JH biosynthesis by incubation of tissue in synthetic Manduca sexta allatostatin (Manse-AST, pGlu-Val-Arg-Phe-Arg-Gln-Cys-Tyr-Phe-Asn-Pro-Ile-Ser-Cys-Phe-COOH) reduced production of these chemicals to negligible levels. However, incubation of tissue in the presence of Manse-AST plus farnesol resulted in production of significant amounts of both methyl farnesoate and JH III. Tissue incubated in the presence of Manse-AST plus methyl farnesoate produced only JH III. The results indicated that methyl farnesoate is naturally produced by the corpora allata of adult females of Heliothis virescens. However, tissue incubated in the presence of Manse-AST plus JH III acid also produced JH III in amounts equivalent to that produced by tissue incubated with methyl farnesoate. Thus, both methyl farnesoate and JH III acid could serve as a precursor for biosynthesis of JH III.