Effect of four different nutrition regimes on the alpha-amylase gene expression in the Indian moth,Plodia interpunctella

Plodia interpunctella (Hübner 1813) (Lepidoptera: Pyralidae) is a cosmopolitan species known to infest a wide range of dried plant materials, including legumes and cereals. In this study, enzyme activity and expression of alpha-amylase gene in larval P. interpunctella grown on four different nutrition regimes was studied. The different nutrition regimes caused differential change in expression of alpha-amylase gene. Compared with the control (artificial diet), the walnut regime caused a 10.8% increase in expression of the alpha-amylase gene, whereas 79.3, 52.5, and 7.5% decreases were observed in the larvae grown on dates, raisins and oleaster respectively. The results also showed that glucose repression varied among larvae feeding on different food diets. The results revealed that expression of the alpha-amylase coding gene was significantly reduced in the larvae grown on date and raisin containing high amounts of glucose. A biochemical assay indicated overlapping of alpha-amylase activity and expression. Complexity in expression of amylase genes suggests the existence of a negative feedback mechanism in the insect larvae. Different parameters can affect gene expression and activation, which may explain the results presented here.