Bio-potency of a 21 kDa Kunitz-type trypsin inhibitor from Tamarindus indica seeds on the developmental physiology of H. armigera Prabhash K. Pandey, Farrukh Jamal * Department of Biochemistry [DST-FIST UGC-SAP Supported], Dr. Ram Manohar Lohia Avadh University, Faizabad, Uttar Pradesh 224001, India ARTICLE INFO Article history: Received 1 June 2014 Accepted 3 October 2014 Available online 13 October 2014 Keywords: Trypsin inhibitor H. armigera Larvicidal Fecundity Developmental physiology Toxicity A B ST R AC T A trypsin inhibitor purified from the seeds of Tamarindus indica by Sephadex G-75, DEAE-Sepharose and Trypsin-Sepharose CL-4B columns was studied for its antifeedant, larvicidal, pupicidal and growth in- hibitory activities against Helicoverpa armigera larvae. Tamarindus trypsin inhibitor (TTI) exhibited inhibitory activity towards total gut proteolytic enzymes of H. armigera (~87%) and bovine trypsin (~84%). Lethal doses which caused mortality and weight reduction by 50% were 1% w/w and 0.50% w/w, respectively. IC50 of TTI against Helicoverpa midgut proteases and bovine trypsin were ~2.10 μg/ml and 1.68 μg/ml re- spectively. In larval feeding studies the 21 kDa Kunitz-type protein was found to retard growth and development, prolonged the larval–pupal development durations along with adversely affecting the fer- tility and fecundity of H. armigera. In artificial diet at 0.5% w/w TTI, the efficiency of conversion of ingested food as well as of digested food, relative growth rate, growth index declined whereas approximate di- gestibility, metabolic cost, relative consumption rate, consumption index and total developmental period enhanced for H. armigera larvae. These results suggest that TTI has toxic and adverse effect on the de- velopmental physiology of H. armigera and could be useful in controlling the pest H. armigera. © 2014 Elsevier Inc. All rights reserved. 1. Introduction The development of resistance to inhibitors in insects in the near future has necessitated the search for newer and more effective bi- ological means of controlling insects. Inhibitors from diverse sources are being explored for understanding their inhibitory potential. Among several alternatives, protease inhibitors (PIs) represent an attractive class of biopesticides with several important features. Such protease inhibitors are environmentally friendly and can work as defence molecules against plant pests and pathogens [1,2]. Helicoverpa armigera is one of the key devastating pests. It infests several nutritionally and economically valuable crops thereby causing severe loss in yield. The factors contributing to its severity in dif- ferent situations are multi-voltinism, high fecundity and ability to migrate long distances and diapauses [3,4]. Further, the intrinsic abundance of different proteases in its midgut that are differen- tially regulated poses an enormous challenge to counter inhibition using a single plant’s PI(s) [5]. Therefore, orchestrating the expression of different and novel inhibitors in a concerted manner would be a wise and sustainable approach in effective pest control strategy. Moreover, host–pest interactions culminates to co- evolution of host resistance and pest adaptation which demands not only identifying novel bioactive molecules but also the devel- opment of better and unique strategies for both plants and pests to overcome each other’s defence capabilities. The lepidopteran larvae are ‘eating machines’, and with a strong metabolic processes they exhibit much faster growth and devel- opment [6]. The selection of target molecules, such as digestive enzymes and/or the chitin present in the peritrophic membrane, a film-like structure that separates food from the gut tissue of many insect pests is gaining emphasis in alternative pest control strate- gies [7]. Thus, novel gene pools from wild varieties of plants with more important and versatile properties must be explored so that these genes/gene product(s) can be exploited for developing crops that can be efficiently managed and the use of dangerous pesti- cides can be restricted. Interestingly, in a coevolving plant–insect interaction choosing non-host plant represents one of the best sources of identifying effective PIs [8,9]. Tamarindus indica (Indian Date, kilytree) belongs to the family Leguminosae and has been used in traditional Ayurvedic herbal med- icine. Its fruit pulp is an important food ingredient, an emulsifier and used as a stabilizer in the food industry [10]. The present article explores the effectiveness of a purified non-host trypsin inhibitor from Tamarindus indica seeds on the developmental physiology of H. armigera. * Corresponding author. Department of Biochemistry [DST-FIST & UGC-SAP Supported], Dr. Ram Manohar Lohia Avadh University, Faizabad, Uttar Pradesh 224001, India. Fax: +91 05278 246330. E-mail addresses: farrukhrmlau@gmail.com; journal.farrukh@gmail.com (F. Jamal). http://dx.doi.org/10.1016/j.pestbp.2014.10.001 0048-3575/© 2014 Elsevier Inc. All rights reserved. Pesticide Biochemistry and Physiology 116 (2014) 94–102 Contents lists available at ScienceDirect Pesticide Biochemistry and Physiology journal homepage: www.elsevier.com/locate/pest