Peptidase inhibitors (PIs) are plant proteins that are found to be effective against various digestive peptidases of insects. The present study isolated and characterized a trypsin inhibitor from mature dry seeds of Mucuna pruriens and investigated its effect against Bactrocera cucurbitae larvae, a major pest of cucurbitaceae crops, for its inhibitory activity. The purified trypsin inhibitor from M. pruriens seeds gave a molecular weight of ~11 kDa on SDS-PAGE. M. pruriens trypsin inhibitor (MPTI) exhibited inhibitory effect on growth of melon fruit fly larvae (64-72 h old) as it resulted in prolongation of larval, pupal and total development period. There was a significant increase in larval mortality with increase in concentration of MPTI. Nutritional indices decreased significantly at all the concentrations of MPTI. Quantitative RT- PCR revealed that the mRNA expression level of trypsin and chymotrypsin genes was reduced while that of GST, esterases, AP, SOD and catalase were enhanced. It can therefore be inferred that MPTI can serve as a promising agent for biocontrol that can reduce the problems caused by fruit fly and other similar catastrophic pests. This study provides the fundamental information for future successful strategies for pest management.

中文翻译：

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从黧豆种子中纯化的胰蛋白酶抑制剂对葫芦巴果蝇幼虫消化生理的恶化

肽酶抑制剂 (PI) 是一种植物蛋白，被发现可有效对抗昆虫的各种消化肽酶。本研究从 Mucuna pruriens 的成熟干燥种子中分离并表征了一种胰蛋白酶抑制剂，并研究了其对葫芦科作物主要害虫葫芦科实蝇幼虫的抑制活性。来自 M. pruriens 种子的纯化胰蛋白酶抑制剂在 SDS-PAGE 上的分子量约为 11 kDa。M. pruriens 胰蛋白酶抑制剂 (MPTI) 对瓜果蝇幼虫（64-72 小时龄）的生长具有抑制作用，因为它导致幼虫、蛹和总发育期的延长。随着 MPTI 浓度的增加，幼虫死亡率显着增加。营养指数在所有 MPTI 浓度下均显着下降。定量RT-PCR显示胰蛋白酶和胰凝乳蛋白酶基因的mRNA表达水平降低，而GST、酯酶、AP、SOD和过氧化氢酶的mRNA表达水平增强。因此可以推断，MPTI 可以作为一种有前途的生物防治剂，可以减少由果蝇和其他类似灾难性害虫引起的问题。这项研究为未来有害生物管理的成功策略提供了基本信息。