Characterization of gene expression patterns during the initiation and maintenance phases of diapause in the Colorado potato beetle, Leptinotarsa decemlineata

Abstract

Using differential display, 55 differentially regulated transcripts were isolated from the Colorado potato beetle, Leptinotarsa decemlineata (Say). The insert sizes of the clones ranged from 114 to 795 bp. Fourteen of the transcripts were confirmed by northern blot analysis to be differentially regulated transcripts with respect to the diapause initiation and maintenance phases. Based on Blast search results, these 14 transcripts were assigned putative identities and placed into four broad categories of proteins: unknown function, defensive, structural/glycine-rich, and digestive. The transcripts were highly expressed for the first 13–15 days postemergence during the diapause initiation and early diapause maintenance phases and were then substantially down-regulated. These down-regulated transcripts were also highly expressed for the first seven days postemergence in nondiapausing adults and their expression became more variable on day 9 or 11 in most individuals examined. The glycine-rich protein transcripts were all down-regulated by day 11 in the nondiapausing adults. A comparison of the transcript expression patterns between diapause initiation phase and nondiapausing adults showed that elevated levels of expression of the glycine-rich transcripts and two transcripts with unknown functions persisted for approximately four days longer in the diapause-programmed beetles.