Effect of α-amylase inhibitor from Withania somnifera on growth and development of Callosobruchus chinensis and in silico studies on its interactions with insect amylase

Abstract

Pulse beetle (Callosobruchus chinensis) is a cosmopolitan stored grain pest of legumes responsible for significant losses in them during storage. A proteinaceous α-amylase inhibitor, isolated and purified from Withania somnifera (WSAI), affected various growth and developmental parameters of Callosobruchus chinensis. Whereas female fecundity, adult emergence and % seed damaged were found to be reduced, mean development period and feeding deterrence index increased as a function of WSAI treatment. Almost 59% relative amylase activity was observed at 50 µg/mL of WSAI and confirmed by starch activity gel assay. Longevity of survived insects of treated sets was reduced by 2 days compared to control sets. Possible homology modelled structures for WSAI and C. chinensis proteins were proposed. The In-silico protein-protein docking studies revealed the hydrogen bonding network, binding energy (−16.5 Kcal) and amino acids involved in forming interactions which will be helpful in understanding the mechanism of inhibition in future.

Graphical Abstract

Keywords:

• α-amylase inhibitor
• adzuki weevil
• grain legumes
• homology modelling
• protein-protein docking

Disclosure statement

The authors report no conflict of interests.

Authors contributions

S.S.K carried out the experiments and wrote the manuscript with support from P.K.P and V.L.M. V.B.S. helped in bioinformatics study and R.A.S. helped in the insect bioassay. P.K.P. and V.L.M. verified the analytical methods and supervised the findings of this work. All authors discussed the results and contributed to the final manuscript.

Additional information

Funding

This work was supported by the Department of Science and Technology, New Delhi under its DST-INSPIRE scheme (grant number IF150342 to SSK); UGC-SAP–DRS grant [F.4-23/2015/DRS-II (SAPII)]) and DST-FISTgrant [SR/FST/LSI-433/2010) to School of Life Sciences, K.B.C. North Maharashtra University, Jalgaon, M.S., India.