The Entomocidal Crystal Proteins Cry1Ac and Cry2Ab and Their Relationship to Physiological Responses in Egyptian Cotton Leafworm, Spodoptera littoralis (Boisd.)

Document Type : Original Article

Authors

1 Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, Egypt

2 Plant Protection Department, Faculty of Agriculture, Sohag University, Egypt

Abstract

The current work was carried out to evaluate the biochemical effects of LC50 of the Bacillus thuringiensis as spores against Spodoptera littoralis 2nd and 4th instars and Cry1Ac and Cry2Ab against newly hatched larvae to determine the effects of these compounds on total carbohydrates, proteins,lipids, acetylcholinesterase, chitinase, phenoloxidase, carbohydrates hydrolyzing enzymes, nonspecific esterases, phosphatases and transaminase enzymes.   The obtained results indicated that total proteins and lipids content were highly significantly decreased and a highly significantly increased in total carbohydrates with B. thuringiensis spores for both instars. A highly significant decrease in total carbohydrates with Cry1Ac and increased with Cry2Ab. While total protein was highly significantly increased with Cry1Ac and decreased with Cry2Ab. The activity of invertase and trehalase were highly significantly decreased with B. thuringiensis spores for both instars. On the other side, A highly significantly increased in amylase and invertase enzyme activity with Cry1Ac and decreased with Cry2Ab. In contrast, Cry1Ac and Cry2Ab caused a highly significant decrease in trehalase activity. It is clearly noticed that B. thuringiensis spores significantly increased GOT for both instarslarvae,in contrast, GPT was highly significantly increased in 2nd instar larvae only. While GOT activates were a highly significant dropped with Cry1Ac and Cry2Ab. Alpha esterase was highly significantly activated with B. thuringiensis spores in 2nd instar larvae and inhibition in 4th instar larvae while Beta esterase and Acetylcholinesterase enzymes activities were a highly significant increase in both instars larvae. On the other side, Alfa, beta esterase and acetylcholinesterase were highly significantly decreased with Cry1Ac and increased with Cry2Ab.

Keywords