Kramer K J, Muthukrishnan S
Grain Marketing and Production Research Center, Agricultural Research Service, U.S. Department of Agriculture, Manhattan, KS 66502-2736, USA.
Insect Biochem Mol Biol. 1997 Nov;27(11):887-900. doi: 10.1016/s0965-1748(97)00078-7.
Chitin, an insoluble structural polysaccharide that occurs in the exoskeletal and gut linings of insects, is a metabolic target of selective pest control agents. One potential biopesticide is the insect molting enzyme, chitinase, which degrades chitin to low molecular weight, soluble and insoluble oligosaccharides. For several years, our laboratories have been characterizing this enzyme and its gene. Most recently, we have been developing chitinase for use as a biopesticide to control insect and also fungal pests. Chitinases have been isolated from the tobacco hornworm, Manduca sexta, and several other insect species, and some of their chemical, physical, and kinetic properties have been determined. Also, cDNA and genomic clones for the chitinase from the hornworm have been isolated and characterized. Transgenic plants that express hornworm chitinase constitutively have been generated and found to exhibit host plant resistance. A transformed entomopathogenic virus that produces the enzyme displayed enhanced insecticidal activity. Chitinase also potentiated the efficacy of the toxin from the microbial insecticide, Bacillus thuringiensis. Insect chitinase and its gene are now available for biopesticidal applications in integrated pest management programs. Current knowledge regarding the molecular biology and biopesticidal action of insect and several other types of chitinases is described in this mini-review.
几丁质是一种不溶性结构多糖，存在于昆虫的外骨骼和肠道内膜中，是选择性害虫防治剂的代谢靶点。一种潜在的生物农药是昆虫蜕皮酶——几丁质酶，它能将几丁质降解为低分子量的可溶性和不溶性寡糖。多年来，我们实验室一直在对这种酶及其基因进行表征。最近，我们一直在开发将几丁质酶用作生物农药来防治昆虫和真菌害虫。几丁质酶已从烟草天蛾（Manduca sexta）和其他几种昆虫物种中分离出来，并且已经确定了它们的一些化学、物理和动力学特性。此外，已分离并表征了来自烟草天蛾的几丁质酶的cDNA和基因组克隆。已培育出组成型表达烟草天蛾几丁质酶的转基因植物，并发现其具有宿主植物抗性。一种产生该酶的转化昆虫病原病毒表现出增强的杀虫活性。几丁质酶还增强了微生物杀虫剂苏云金芽孢杆菌毒素的功效。昆虫几丁质酶及其基因现在可用于综合害虫管理计划中的生物农药应用。本综述简述了有关昆虫及其他几种几丁质酶的分子生物学和生物农药作用的当前知识。
