Genome wide microarray based expression profiles during early embryogenesis in diapause induced and non-diapause eggs of polyvoltine silkworm Bombyx mori

• 638 and 1136 genes were found to be up- and down-regulated at 18 h after oviposition.
• 675 And 595 genes were found to be up- and down-regulated at 30 h after oviposition.
• qPCR confirmed the expression of 20 genes either up- or down-regulated.
• Aquaporin, SDH-2, cytochrome b5 gene expressions were higher in diapause eggs.
• Kr-h1, period and Relish gene expressions were higher in non-diapause eggs.

Diapause was induced in polyvoltine silkworm B. mori eggs and the molecular mechanism involved in diapause was investigated using a genome wide microarray. In diapause eggs, 638 and 675 genes were upregulated, while, in non-diapause eggs 1136 and 595 genes were upregulated at 18 h and 30 h, respectively after oviposition. Real-time qPCR analysis confirmed the expression of 20 genes, and the relative expression levels of the Aquaporin gene was highest among the 20 genes, followed by Sorbitol dehydrogenase-2 and Cytochrome b5 in diapause eggs, while, Kruppel homolog, Period and Relish were higher in non-diapause eggs. The upregulation of SDH-2 and cytochrome b5 indicates increased metabolic rate in diapause-destined embryos prior to the onset of diapause within 36 h as a preparatory phase. This study provides an insight into the early molecular events for the induction and maintenance of diapause in B. mori.