Effect of different soybean varieties on proteolytic activities of digestive enzymes of Spodoptera exigua (Lepidoptera: Noctuidae)

The beet armyworm, Spodoptera exigua (Lep.: Noctuidae) is an important and polyphagous pest inIran. Effect of nine soybean cultivars (033, Hill, L17, BP and Zane) on proteolytic activities of digestiveenzymes of the beet armyworm was determined at 25 ± 1°C, 60 ± 5% RH and a photoperiod of 16:8(L:D) hours. For sample preparation, the midgut of about 2-day-old fifth instar larvae of S. exigua, wereused. Midgut extracts from larvae showed an optimum activity for proteolysis against azocasein atalkaline pH (10). Casein zymogram analysis revealed 4-7 proteinase bands in the larval midgut extractand strongly showed the presence of trypsin-like serine proteinases. Although the highest total proteolyticactivity was on larvae fed on Zane and Bp varieties, the lowest tryptic activity was observed also on Zaneand BP, which could be due to the presence of serine protease inhibitors (TLCK) in these two varieties,resulting in hyper production of chymotrypsin in response to the inhibition of the serine protease.

کلیدواژه ها:

Beet armyworm ، Soybean cultivars ، Digesive enzymes ، Proteolytic