Main content area

Purification of a trypsin inhibitor from Psoralea corylifolia seeds and its influence on developmental physiology of Bactrocera cucurbitae

Samiksha,, Singh, Drishtant, Kesavan, Anup Kumar, Sohal, Satwinder Kaur
International journal of biological macromolecules 2019 v.139 pp. 1141-1150
Cullen corylifolium, Zeugodacus cucurbitae, affinity chromatography, artificial diets, biological control agents, catalase, chymotrypsin, elastase, fruit flies, gene expression regulation, genes, high performance liquid chromatography, ion exchange, larvae, larval development, melons, molecular weight, mortality, nutrition assessment, pH, pests, polyacrylamide gel electrophoresis, pupae, quantitative polymerase chain reaction, reverse transcriptase polymerase chain reaction, seeds, superoxide dismutase, temperature, trypsin, trypsin inhibitors
A trypsin inhibitor was purified from the seeds of Psoralea corylifolia by ion-exchange and affinity chromatography. The purified fractions were subjected to RP- HPLC which resolved into a single peak. SDS-PAGE analysis gave an apparent molecular weight of 18 kDa. P. corylifolia trypsin inhibitor (PCTI) was found to be a competitive inhibitor and was active over a broad temperature (10–100 °C) and pH (6–11) range. It was shown to have a deleterious effect on growth and development of larvae of the melon fruit fly, Bactrocera cucurbitae, when incorporated in artificial diet using various concentrations. The larval, pupal, total development period and larval mortality significantly increased during the treatment. Inhibitory effects were also observed on percentage emergence which was significantly reduced. Nutritional indices namely food assimilated (FA) and mean relative growth rate (MRGR) also decreased significantly with increase in concentration of PCTI. qRT-PCR results indicated that the expression of trypsin and chymotrypsin genes were down-regulated while elastase, catalase, GST, SOD and AP were up-regulated. PCTI was also effective against certain bacterial strains. These results indicated that the peptidase inhibitor from P. corylifolia may be a potential bio-control agent which can decrease the damage caused by B. cucurbitae and other related destructive pests.