Liu Sijun, Li Huarong, Sivakumar S, Bonning Bryony C
Department of Entomology, Iowa State University, Ames, Iowa 50011, USA.
Adv Virus Res. 2006;68:427-57. doi: 10.1016/S0065-3527(06)68012-3.
Insect viruses have evolved to counter physiological barriers to infection presented by the host insect. For the Lepidoptera (butterflies and moths), these barriers include (1) the peritrophic membrane (PM) lining the gut, which presents a physical barrier to virus infection of the midgut epithelial cells, (2) the basement membrane (BM) that overlies the gut thereby restricting secondary infection of other tissues, and (3) the immune system of the host insect. Hence, insect viruses provide a resource for genes that disrupt host physiology in a specific manner, and these genes in turn serve as a resource both for the study of physiological processes, and for disruption of these processes for pest management purposes. There are several examples of the application of genes used by an insect virus to overcome the PM barrier for production of insect-resistant transgenic plants. There are other examples of intrahemocoelic effectors, such as BM-degrading proteases that can only be used with an appropriate system for delivery of the agent from the gut into the hemocoel (body cavity) of the insect pest. In this chapter, we describe (1) baculovirus- and entomopoxvirus-derived genes that alter the physiology of the host insect, (2) use of these and homologous genes for production of insect-resistant transgenic plants, (3) other viral genes that have potential for use in development of insect-resistant transgenic plants, and (4) the use of plant lectins for delivery of intrahemocoelic toxins from transgenic plants. Plant expression of polydnavirus-derived genes is described by Gill et al. (this volume, pp. 393-426).
昆虫病毒已经进化出应对宿主昆虫所呈现的感染生理屏障的能力。对于鳞翅目昆虫（蝴蝶和蛾类）而言，这些屏障包括：（1）肠道内衬的围食膜（PM），它对中肠上皮细胞的病毒感染构成物理屏障；（2）覆盖在肠道上方的基膜（BM），从而限制其他组织的二次感染；以及（3）宿主昆虫的免疫系统。因此，昆虫病毒为以特定方式破坏宿主生理机能的基因提供了资源，而这些基因反过来又为生理过程的研究以及为害虫治理目的而破坏这些过程提供了资源。有几个利用昆虫病毒所使用的基因来克服围食膜屏障以培育抗虫转基因植物的例子。还有其他血腔效应子的例子，比如能够降解基膜的蛋白酶，但只有在合适的系统中将该因子从肠道递送至害虫血腔（体腔）时才能使用。在本章中，我们描述了：（1）杆状病毒和昆虫痘病毒衍生的改变宿主昆虫生理机能的基因；（2）利用这些基因和同源基因培育抗虫转基因植物；（3）其他有潜力用于培育抗虫转基因植物的病毒基因；以及（4）利用植物凝集素来从转基因植物中递送血腔毒素。Gill等人（本卷，第393 - 426页）描述了多DNA病毒衍生基因在植物中的表达。
