Girard C, Le Métayer M, Bonadé-Bottino M, Pham-Delègue M H, Jouanin L
Laboratoire de Biologie Cellulaire, INRA de Versailles, France.
Insect Biochem Mol Biol. 1998 Apr;28(4):229-37. doi: 10.1016/s0965-1748(98)00027-7.
Incorporation of genes encoding proteinase inhibitors into oilseed rape genome could confer resistance to Coleoptera, which are the major pests on rape in Europe. A detailed study of the digestive proteinase of a model cruciferous-feeding Coleoptera, Phaedon cochleariae, showed that this insect relies on a complex proteolytic system including serine, cysteine, aspartyl proteinases, and leucine aminopeptidases. The inhibition of general and specific activities by a range of proteinase inhibitors in vitro suggested that oryzacystatin I (OCI) and Bowman-Birk inhibitor (BBI) would have adverse effects when ingested by the larvae. However, the growth and the feeding of larvae reared on oilseed rape leaf discs treated with a high dose of OCI and/or BBI were not affected. Moreover, the levels and patterns of proteolytic activities were not modified in these larvae. The study of the interactions between P. cochleariae larval proteinases and OCI and BBI revealed that both inhibitors were rapidly cleaved by serine proteinases in association with leucine aminopeptidases, and consequently lost their inhibitory capacity. This mechanism of resistance is very efficient, and may be widespread among Coleoptera. The major implications for insect control using proteinase inhibitor-based strategies are discussed.
将编码蛋白酶抑制剂的基因整合到油菜基因组中，可以使油菜获得对鞘翅目昆虫的抗性，鞘翅目昆虫是欧洲油菜的主要害虫。对一种以十字花科植物为食的典型鞘翅目昆虫——菜蓝叶甲的消化蛋白酶进行的详细研究表明，这种昆虫依赖于一个复杂的蛋白水解系统，该系统包括丝氨酸蛋白酶、半胱氨酸蛋白酶、天冬氨酸蛋白酶和亮氨酸氨肽酶。一系列蛋白酶抑制剂在体外对一般活性和特定活性的抑制作用表明，水稻巯基蛋白酶抑制剂I（OCI）和鲍曼-伯克抑制剂（BBI）被幼虫摄入后会产生不利影响。然而，用高剂量的OCI和/或BBI处理过的油菜叶片圆盘饲养的幼虫的生长和取食并未受到影响。此外，这些幼虫体内蛋白水解活性的水平和模式也没有改变。对菜蓝叶甲幼虫蛋白酶与OCI和BBI之间相互作用的研究表明，这两种抑制剂都能与亮氨酸氨肽酶一起被丝氨酸蛋白酶迅速裂解，因此失去了它们的抑制能力。这种抗性机制非常有效，可能在鞘翅目昆虫中广泛存在。本文还讨论了使用基于蛋白酶抑制剂的策略进行昆虫防治的主要意义。
