Functional Constraints of Enzymatic activity of Tobacco Cutworm in Response to endophytic Aspergillus terreus

Author: Surbjit Singh, Amarjeet Kaur and Sanehdeep Kaur

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Abstract

Endophytic fungi which live within the plant tissues asymptomatically are important mediators of plant-herbivore interactions. Secondary metabolites produced by the fungi or by plants as a result of interactions with fungi have been related to the anti-herbivore properties of fungal endophytes. To cope up from the harmful effects of these mycotoxins, insects have evolved a number of defense mechanisms, such as the production of digestive and detoxifying enzymes. These enzymes help in the detoxification of harmful plant metabolites and have positive effects on insects by breaking down complex compounds into simpler forms. Keeping in view the insecticidal potential of endophytic fungi, the present investigation has been undertaken to analyze the effect of ethyl acetate extract of endophytic Aspergillus terreus on the digestive and detoxifying enzymes of Spodoptera litura (Fabricius). After feeding the larvae on a diet containing fungal extract (LC50 = 2.31 mg/ml), the enzyme activity was assessed after 48 and 96 hours. The findings showed that when the larvae were fed supplemented diet, the activity of digestive enzymes such as α-amylase, α and β-glucosidases, and α and β-galactosidases reduced. Similarly detoxifying enzymes i.e. phosphatases, esterases, and GSTs have also been shown to be inhibited. It was also determined how endophyte infected cauliflower plants influence the digestive and detoxifying enzymes of S. litura. The results revealed that the larvae consuming endophyte-infected plants had reduced levels of activity in their detoxifying and digestive enzymes. In conclusion, the endophytic A. terreus exhibits enzyme inhibitory activity against S. litura.

Keywords

Aspergillus terreus, Spodoptera litura, secondary metabolites, digestive and detoxifying enzymes

Conclusion

It is evident from this work that S. litura's digestive and detoxifying enzyme activity was significantly affected by the diet supplemented with ethyl acetate extract and endophyte-infected plants. The intestinal epithelium's ability to absorb nutrients can also be hindered by suppressed levels of digestive enzymes. The induction of digestive enzymes depends on feeding. As a result, a recent study by Singh et al., (2021) suggests that reduction of the activity of several digestive enzymes may be correlated with decreased consumption rate. Similarly, reduced detoxification enzyme activity is associated with the toxic effects of secondary metabolites produced by endophytic fungi on S. litura midgut epithelial cells, as secondary metabolites are known to induce cytotoxic effect (Edriss et al., 2012; Wink 2018; Mousavi and Karami 2022). Secondary metabolites of entomopathogenic fungi cause death by interfering with the insect host’s defense mechanisms (Gillespie and Claydon 1989, Zibaee et al., 2011). Thus this study shows secondary metabolites produced by endophytic A. terreus act as enzyme inhibitors.

References

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How to cite this article

Surbjit Singh, Amarjeet Kaur and Sanehdeep Kaur (2023). Functional Constraints of Enzymatic activity of Tobacco Cutworm in Response to endophytic Aspergillus terreus. Biological Forum – An International Journal, 15(5): 1567-1575.