Effect of Four Different Nutrition Regimes on the Alpha-Amylase Gene Expression in Plodia interpunctella Hubner (Lepidoptera: Pyralidae)

Plodia interpunctella Hubner (Lepidoptera: Pyralidae) is a cosmopolitan species known to infest a wide range of dried plant materials, including legumes and cereals. In this study, after confirmation of the presence of alpha-amylase gene in samples using gene specific primers, total RNA was extracted from fifth instar larvae of P. interpunctella, grown on the five different nutrition regimes including pistachio, white mulatto, plum, wheat and artificial diet (as control). After synthesis of cDNA, change in gene expression was studied with Real-time PCR assay. PCR performance test indicates 99 and 98% amplification efficiency for SiAmy and SiAmyC primers, respectively. Different nutrition regimes caused differential change in the expression of the gene. In comparison with the control, pistachio regime caused 5% increase in the expression of the alpha-amylase gene, wherease 10%, 27% and 60% decreases were observed in the larva grown on plum, wheat and mulatto respectively. Maximum variation in expression of alpha-amylase gene was observed in the larvae fed on mulatto. The results showed that the inhibition of alpha-amylase gene expression varied in the different sources of glucose in larvae fed on different diets and there was a negative correlation between the amount of sugar in the diet and alpha-amylase gene expression.