مطالعه ارتباط بین فعالیت آنزیم‌های گوارشی کرم برگ‌خوار مصری پنبه،Spodoptera littoralis (Boisd) (Lepidoptera: Noctuidae)، با متابولیت‌های بیوشیمیایی سبزیجات مختلف

The Egyptian cotton leafworm, Spodoptera littoralis (Boisd) (Lepidoptera: Noctuidae), is the most important and effective factor in decreasing quality and quantity of various leafy vegetables in Iran and many parts of the world, and damaging of economic in the throughout world. In current research, the effects of seven different leafy vegetables, including Perpin, Chives, Parsley, Basil, Dill, Coriander and Mint hosts assessed on proteolytic and amylolytic digestive enzymes activities of S. littoralis in a growth chamber at 25 ± 1°C, 60 ± 5% RH, and a photoperiod of 16:8 (L:D) hours. Furthermore, in this study, some secondary metabolites of different vegetable hosts, including phenolic, flavonoid and anthocyanin content were estimated to correlations between these biochemical compounds with digestive properties of pest were determined. The results showed that significant differences were observed in the activities of digestive proteases and amylases in larval of S. littoralis fed on the different hosts. The larvae fed on coriander host (0.734 mU/mg) showed the highest levels of general amylolytic activity, and lowest activity was recorded on the Perpin vegetable (0.136 mU/mg) using starch the substrate. The highest general proteolytic activity was obtained in the larvae fed on Dill vegetable (2.394 U/mg) and lowest on Perpin host (0.829 U/mg) using azocasein as the substrate. The optimal pH of amylolytic and proteolytic digestive enzymes activities in the larvae fed on various vegetables were obtained a pH range of 9-12. Significant differences were observed in metabolites of phenolic, flavonoid and anthocyanin content among the various hosts. The highest total phenolic value was in the coriander vegetable (129.68 mg/ml) while the lowest value was in the Perpin host (14.12 mg/ml). The highest flavonoid content value was obtained for the Perpin host (331.22 mg/ml) and the lowest value was the Chives vegetable (119 mg/ml). Furthermore, the highest value of anthocyanin was observed in Parsley host (0.5 mg/ml) and the lowest value was in Chives vegetable (0.05 mg/ml). In this study, all biochemical characteristics of tested vegetable hosts were significant differences and significant positive or negative correlations were observed between secondary plant metabolites with digestive enzymes of insect pests. The cluster results based on digestive and biochemical properties showed that Dill and Coriander vegetables were relatively susceptible (suitable) hosts and Perpin vegetable was the relatively resistant (least appropriate) hosts for S. littoralis. Regarding the results, Dill and Coriander were found to be the most suitable hosts in the plant-herbivore interaction.