Genetic resources for arcelin,a stored product insect antimetabolic protein from various accessions of pulses of Leguminosae

Pulses, the most important source of high-quality dietary proteins are prone to serious damage due to insect pests, of which 20–25% damage was inflicted by stored product bruchid pest, Callosobruchus maculatus (F.). An alternative approach to control these insect pests apart from fumigation is the use of primary metabolites involved in plant defense mechanism. In the present study, one of such molecule, an insect anti-metabolic protein, arcelin was screened from nine different wild and cultivated varieties of pulses. Insect feeding bioassay with C. maculatus revealed that seven of these seed varieties were not infested by the bruchid insect pest. Additionally, the presence of arcelin polypeptide subunits (27–42 kDa) was demonstrated in the seeds of Phaseolus limensis L. and Phaseolus lunatus L. whereas, an insignificant amount was observed in Lablab purpureus L. Besides, seed kernel extract of P. lunatus registered a highest HA activity against native human-A erythrocytes and this activity was increased to several fold when the erythrocytes were treated with proteolytic enzymes revealing the characteristic feature of arcelin. Similarly, HA activity was observed when rat and mouse erythrocyte was treated with pronase, whereas, no titer value was observed upon treatment with its native erythrocytes. Of the 24 carbohydrates tested, only acetylated amino sugar, N-acetyl-d-galactosamine inhibited the agglutinating activity of crude seed extract against human-A RBC. Among the three glycoproteins tested, none were found potential to competitively inhibit the agglutination activity against human-A erythrocytes. Overall, this study reveals the presence of arcelin, an anti-metabolic insecticidal protein in seeds of P. lunatus.