Carlini Célia R, Grossi-de-Sá Maria Fátima
Department of Biophysics, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, 91.501-970 Porto Alegre, RS, Brazil.
Toxicon. 2002 Nov;40(11):1515-39. doi: 10.1016/s0041-0101(02)00240-4.
To meet the demands for food of the expanding world population, there is need of new ways for protecting plant crops against predators and pathogens while avoiding the use of environmentally aggressive chemicals. A milestone in this field was the introduction into crop plants of genes expressing Bacillus thuringiensis entomotoxic proteins. In spite of the success of this new technology, however, there are difficulties for acceptance of these 'anti-natural' products by the consumers and some concerns about its biosafety in mammals. An alternative could be exploring the plant's own defense mechanisms, by manipulating the expression of their endogenous defense proteins, or introducing an insect control gene derived from another plant. This review deals with the biochemical features and mechanisms of actions of plant proteins supposedly involved in defense mechanisms against insects, including lectins, ribosome-inactivating proteins, enzymes inhibitors, arcelins, chitinases, ureases, and modified storage proteins. The potentialities of genetic engineering of plants with increased resistance to insect predation relying on the repertoire of genes found in plants are also discussed. Several different genes encoding plant entomotoxic proteins have been introduced into crop genomes and many of these insect resistant plants are now being tested in field conditions or awaiting commercialization.
为满足不断增长的世界人口对食物的需求，需要新的方法来保护农作物免受捕食者和病原体侵害，同时避免使用对环境有危害的化学物质。该领域的一个里程碑是将表达苏云金芽孢杆菌昆虫毒性蛋白的基因导入农作物。然而，尽管这项新技术取得了成功，但消费者对这些“反自然”产品的接受存在困难，并且对其在哺乳动物中的生物安全性也存在一些担忧。一种替代方法可能是通过操纵植物内源性防御蛋白的表达，或引入源自另一种植物的昆虫控制基因，来探索植物自身的防御机制。这篇综述探讨了可能参与植物抗虫防御机制的蛋白质的生化特性和作用机制，包括凝集素、核糖体失活蛋白、酶抑制剂、菜豆球蛋白、几丁质酶、脲酶和修饰的贮藏蛋白。还讨论了利用植物中发现的基因库对植物进行基因工程改造以增强抗虫能力的潜力。几种不同的编码植物昆虫毒性蛋白的基因已被导入作物基因组，许多这些抗虫植物目前正在田间条件下进行测试或等待商业化。
