Midgut tissue of male pine engraver, Ips pini, synthesizes monoterpenoid pheromone component ipsdienol de novo.
For over three decades the site and pathways of bark beetle aggregation pheromone production have remained elusive. Studies on pheromone production in Ips spp. bark beetles have recently shown de novo biosynthesis of pheromone components via the mevalonate pathway. The gene encoding a key regulated enzyme in this pathway, 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-R), showed high transcript levels in the anterior midgut of male pine engravers, Ips pini (Say) (Coleoptera:Scolytidae). HMG-R expression in the midgut was sex, juvenile hormone, and feeding dependent, providing strong evidence that this is the site of acyclic monoterpenoid (ipsdienol) pheromone production in male beetles. Additionally, isolated midgut tissue from fed or juvenile hormone III (JH III)-treated males converted radiolabeled acetate to ipsdienol, as assayed by radio-HPLC. These data support the de novo production of this frass-associated aggregation pheromone component by the mevalonate pathway. The induction of a metazoan HMG-R in this process does not support the postulated role of microorganisms in ipsdienol production.
Hall
Gregory M
GM
Department of Biochemistry, University of Nevada, Reno 89557-0014, USA.
Tittiger
Claus
C
Andrews
Gracie L
GL
Mastick
Grant S
GS
Kuenzli
Marilyn
M
Luo
Xin
X
Seybold
Steven J
SJ
Blomquist
Gary J
GJ
D000818:Animals; D001517:Coleoptera / Q000502:physiology*; D004064:Digestive System / Q000201:enzymology*; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics; D008297:Male; D010675:Pheromones / Q000096:biosynthesis*; D028201:Pinaceae / Q000469:parasitology; D013729:Terpenes / Q000378:metabolism; D014158:Transcription, Genetic; D014197:Trees / Q000469:parasitology
D010675:Pheromones; D013729:Terpenes; D006903:Hydroxymethylglutaryl CoA Reductases