@article { ISI:000326615000007, title = {Molecular insights into resistance mechanisms of lepidopteran insect pests against toxicants}, journal = {Journal of Proteome Research}, volume = {12}, number = {11}, year = {2013}, month = {NOV}, pages = {4727-4737}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Insect pests remain a major reason for crop loss worldwide despite extensive use of chemical insecticides. More than B 50\% of all insecticides are organophosphates, followed by synthetic pyrethroids, organochlorines, carbamates, and biopesticides, and their continued use may have many environmental, agricultural, medical, and socioeconomic issues. Importantly, only a countable number of insects have acquired the status of crop pests, mostly due to monoculture of crop plants and polyphagous nature of the insects. We focus on A adaptations of Lepidopteran insects to phytochemicals and synthetic pesticides in native and modern agricultural systems. Because of heavy use of chemical insecticides, a strong selection pressure is imposed on insect populations, resulting in the emergence of resistance against candidate compound(s). Current knowledge suggests that insects generally implement a three-tier system to overcome the effect of toxic compounds at physiological, biochemical, and genetic levels. Furthermore, we have discussed whether the adaptation to phytochemicals provides an advantage to the insect while encountering synthetic insecticide molecules. Specific metabolic pathways employed by insects to convert deterrents into less toxic forms or their removal from the system are highlighted. Using the proteomics approach, insect proteins interacting with insecticides can be identified, and their modification in resistant insects can be characterized. Also, systems biology studies can offer useful cues to decipher the molecular networks participating in the metabolism of detrimental compounds.

}, keywords = {field crops, insect-pests, insecticide, Lepidoptera, proteomics, resistance mechanisms}, issn = {1535-3893}, doi = {10.1021/pr400642p}, author = {Dawkar, Vishal V. and Chikate, Yojana R. and Lomate, Purushottam R. and Dholakia, Bhushan B. and Gupta, Vidya S. and Giri, Ashok P.} } @article { ISI:000361402900006, title = {Cathepsins of lepidopteran insects: aspects and prospects}, journal = {Insect Biochemistry and Molecular Biology}, volume = {64}, year = {2015}, month = {SEP}, pages = {51-59}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Molecular understanding of lepidopteran physiology has revealed that proteases consist of one of the central regulatory/reacting system for insect growth and survival. Among the various proteases, cathepsins are the most crucial cellular proteases, which play vital roles during insect development. In the present review, we have discussed various aspects of the lepidopteran insect cathepsins, emphasizing their roles in processes like development, growth, metamorphosis, apoptosis and immunity. Cathepsins are categorized into different types on the basis of their sequence diversification, leading to variation in structure and catalytic function. Cathepsins exhibit tissue and stage specific expression pattern which is fine-tuned by a delicate balance of expression, compartmentalization, zymogen activation, inhibition by protein inhibitors and degradation. The indispensability of cathepsins as cellular proteases in the above mentioned processes proposes them as novel targets for designing effective and specific insect controlling strategies. (C) 2015 Elsevier Ltd. All rights reserved.

}, keywords = {Apoptosis, Cathepsin, Cysteine/aspartate protease, Development, Lepidoptera, Pest control, Stress response}, issn = {0965-1748}, doi = {10.1016/j.ibmb.2015.07.005}, author = {Saikhedkar, Nidhi and Summanwar, Aarohi and Joshi, Rakesh S. and Giri, Ashok P.} } @article {46049, title = {Phyto-inspired cyclic peptides derived from plant Pin-II type protease inhibitor reactive center loops for crop protection from insect pests}, journal = {Biochimica ET Biophysica Acta-General Subjects}, volume = {1863}, year = {2019}, month = {AUG}, pages = {1254-1262}, type = {Article}, abstract = {

Background: Natural defence of plants against insect pests involves protease inhibitors (PIs) that interfere with insect digestive proteases. Pin-II type plant PIs are wound inducible upon insect damage and possess multiple inhibitory repeat domains that can inhibit trypsin and chymotrypsin-like proteases in the insect midgut. Yet, their agricultural ex-vivo application is limited due to large molecular size and environmental instability, which could be overcome by small peptides. Methods: Bicyclic peptides were designed by grafting Pin-II PIs derived reactive center loop (RCL) on synthetic tris(bromomethyl)benzene scaffold. In vitro binding with trypsin-like proteases was evaluated by biochemical and biophysical assays, followed by molecular dynamics simulations. In vivo effects on two major lepidopteran insect pests, Helicoverpa armigera and Spodoptera litura were studied upon feeding with peptide treated leaves. Affinity based pull down assays were used to identify target proteins in insect gut. Results: Bicyclic RCLs showed ten-fold enhanced protease inhibition compared to their linear counterparts. They exhibited feeding deterrence and growth reduction of lepidopteran insects. Bicyclic peptides predominantly interact with midgut serine proteases. Possible binding modes involve simultaneous interaction with the active site and specificity-determining residues of insect gut trypsin. Conclusion: Bicyclic peptides are potent inhibitors of serine proteases in the insect midgut. They cause feeding aversion and larval growth retardation. Bi-domain cyclic peptides interact with two sites on trypsin, leading to enhanced efficacy over linear RCL peptides. General significance: Bicyclic peptides mimic natural PIs by inhibiting insect proteases leading to growth reduction, thus, could be used as pest control molecules in agriculture.

}, keywords = {Cyclic peptide, Lepidoptera, Pest control, protease inhibitor, Reactive loop}, issn = {0304-4165}, doi = {10.1016/j.bbagen.2019.05.003}, author = {Sailthedkar, Nidhi S. and Joshi, Rakesh S. and Yadav, Amit K. and Seal, Shubhendu and Fernandes, Moneesha and Giri, Ashok P.} } @article {48164, title = {Functional diversity of the lepidopteran ATP-binding cassette transporters}, journal = {Journal of Molecular Evolution}, volume = {90}, year = {2022}, month = {AUG}, pages = {258-270}, type = {Review}, abstract = {

The ATP-binding cassette (ABC) transporter gene family is ubiquitous in the living world. ABC proteins bind and hydrolyze ATP to transport a myriad of molecules across various lipid-containing membrane systems. They have been studied well in plants for transport of a variety of compounds and particularly, in vertebrates due to their direct involvement in resistance mechanisms against several toxic molecules/metabolites. ABC transporters in insects are found within large multigene families involved in the efflux of chemical insecticides and toxic/undesired metabolites originating from food and endogenous metabolism. This review deals with ABC transporter subfamilies of few agronomically important Lepidopteran pests. The transcriptional dynamics and regulation of ABC transporters during insect development emphasizes their functional diversity against insecticides, Cry toxins, and plant specialized metabolites. To generate insights about molecular function and physiological roles of ABCs, functional and structural characterization is necessary. Also, expansion and divergence of ABC transporter gene subfamilies in Lepidopteran insects needs more systematic investigation. We anticipate that newer methods of insect control in agriculture can benefit from an understanding of ABC transporter interactions with a vast range of natural specialized molecules and synthetic compounds.

}, keywords = {ABC transporters, Bt, insecticide resistance, Lepidoptera, Plant metabolites}, issn = {0022-2844}, doi = {10.1007/s00239-022-10056-2}, author = {Barve, Pranoti R. and Tellis, Meenakshi B. and Barvkar, Vitthal T. and Joshi, Rakesh S. and Giri, Ashok P. and Kotkar, Hemlata M.} }