Is the Diversity of Trypsins in the Insect Midgut a Determinative Factor in Host Plant Selection?

摘要9507361作为对食草性动物的一种防御，许多植物产生与昆虫食草性动物产生的消化酶相互作用的蛋白酶抑制剂。这些抑制剂降低了昆虫消化植物组织的能力。然而，一些昆虫对蛋白酶抑制剂的反应是通过产生不受抑制物影响的消化酶。这种能力可能允许一些昆虫成功取食，并在广泛的植物上快速生长，每种植物使用一套不同的消化酶。这项研究将通过比较两种昆虫来验证这一假设，一种是饮食专家(黑地老虎)，另一种是饮食通才(玉米耳虫)。将在每个物种中分离和鉴定编码被称为胰酶的消化酶的基因，并将确定每种形式的胰酶对抑制剂的敏感性。这些结果应该有助于深入了解以植物为食的昆虫消化酶的多样性和调节，植物蛋白酶抑制剂作为昆虫攻击防御的重要性，以及消化生理学在控制特定昆虫可以捕食的植物范围方面的重要性。最终，这项研究可能会通过控制农业和园艺植物中蛋白酶抑制剂的水平和多样性，和/或扰乱昆虫用来调节消化酶生产和分泌的机制，来开发有效的策略来控制草食性昆虫。

Lay Abstract 9507361 As one defense against herbivory, many plants produce proteinase inhibitors that interact with digestive enzymes produced by insect herbivores. The inhibitors reduce the insect's ability to digest plant tissue. Some insects, however, respond to proteinase inhibitors by producing forms of the digestive enzymes that are not susceptible to the inhibitor. This ability may permit some insects to feed successfully and grow rapidly on a wide range of plants, using a different suite of digestive enzymes for each. This research will test that hypothesis by comparing two insects, a dietary specialist (the black cutworm) and a dietary generalist (the corn earworm). The genes that code for the digestive enzymes called trypsins will be isolated and characterized in each species, and the susceptibility of each form of trypsin to inhibitors will be determined. The results should yield insight into the diversity and regulation of digestive enzymes in plant-eating insects, the importance of plant proteinase inhibitors as defenses against insect attack, and the importance of digestive physiology in controlling the range of plants on which a particular insect can feed. Ultimately, the research may lead to development of effective strategies for controlling herbivorous insects by manipulating the level and diversity of proteinase inhibitors in agricultural and horticultural plants, and/or disrupting the mechanisms that insects use to regulate digestive enzyme production and secretion.