Biochemical Characterization of the Digestive α- and β-glucosidase Enzymes in Larval Instars of Rose Minor Larvae, Allantus viennensis (Hym.: Tenthredinidae)

Document Type : Research Paper

Authors

1 Former MSc. Student, Department of Plant Protection, Faculty of Agriculture, University of Guilan, Rasht, Iran

2 Associate Professor, Department of Plant Protection, Faculty of Agriculture, University of Guilan, Rasht, Iran

3 Assistant Professor, Department of Biochemistry, Tarbiat Modarres University, Tehran, Iran

Abstract

Rose minor larva, Allantus viennensis (Schr.) is one of the serious pests of roses in Guilan province. The young larvae feed gregariously on the parenchyma of the youngest leaves as they grow, eventually eating the entire leaf parts except the main rib. Glucosidases α- and β- play important roles in the final stages of the insect's carbohydrate digestion. The effect of pH and temperature were investigated on α- and β-glucosidase activities. Results revealed high α- and β-glucosidase activities at pH 6. Also, optimum temperatures were recorded 40 and 50 °C for α- and β-glucosidase activity, respectively. The specific activity of α- and β-glucosidase in digestive system of the 2nd, 3rd, 4th, and 5th larval instars and in the foregut, midgut and hindguts were also determined. Results indicated that with an increase in the larval instar, the α- and β-glucosidase specific activities were also increased. The α- and β-glucosidase specific activities were higher in the midgut than those in the fore, and hindguts. The α- glucosidase specific activities in the digestive system of the 2nd, 3rd, 4th, and 5th larval instars, and as well in the foregut, midgut and hindguts were higher than those for β-glucosidse specific activities. KM values of α-glucosidase, and β-glucosidase were recorded as 2.72 and 2.02 mM, respectively. Zymogram analysis revealed the existence of one form of enzyme in each of the α- and β-glucosidases in the insect's alimentary canal.

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History

  • Receive Date: 09 October 2012
  • Revise Date: 25 November 2013
  • Accept Date: 24 September 2013

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