EUROPEAN JOURNAL OF ENTOMOLOGY

Eur. J. Entomol. 100 (2): 245-250, 2003 | DOI: 10.14411/eje.2003.039

Enhanced expression of genes in the brains of larvae of Mamestra brassicae (Lepidoptera: Noctuidae) exposed to short daylength or fed Dopa

Masahide URYU, Yohsuke NINOMIYA, Takeshi YOKOI, Seiji TSUZUKI, Yoichi HAYAKAWA^*

Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan

The cabbage armyworm, Mamestra brassicae, enters diapause in the early pupal stage. Pupal diapause is induced by rearing the larvae under short day lengths. We previously demonstrated that feeding Dopa during last larval instar induces pupal diapause even under long day lengths. In order to elucidate the mechanism by which pupal diapause is induced after experiencing short day lengths or fed Dopa under long day lengths, we analyzed gene expression in the brain of M. brassicae larvae under both of these conditions using a subtractive hybridization technique. After the secondary screen, 49 clones and 28 clones were identified as short day length or Dopa-feeding specific clones, respectively. All of these genes were sequenced and, using the base sequences of these clones, primers were synthesized. To confirm the genes enhanced specifically by these conditions, quantitative real-time PCR was carried out. This quantitative PCR analysis identified 15 and 1 clone whose expression was enhanced by the short day length conditions or Dopa-feeding, respectively. Among these clones, the gene with a high level of identity to receptor for activated protein kinase C (RACK) from Heliothis virescens is the most dramatically up-regulated under both conditions.

Keywords: Diapause, Mamestra brassicae, cabbage armyworm, brain, short day, Dopa, dopamine, gene expression, receptor for activated C-kinase

Received: August 21, 2002; Revised: February 3, 2003; Accepted: March 17, 2003; Published: June 25, 2003  Show citation