转基因植物中外源基因及其表达产物转移的途径

随着转基因植物商品化应用的增多，全面了解转基因植物潜在的生态风险性尤为重要。国内外对“转基因植物中外源基因向野生亲缘物种漂移的可能性”、“昆虫对抗虫转基因植物的耐受性”以及“转基因植物对生物多样性的潜在影响”等问题已进行了广泛研究。对转基因植物中外源基因及其表达产物的几种可能转移途径作了概述。着重介绍了“经花粉散布或与野生亲缘物种杂交等途径引起的外源基因转移”以及“转基因植物对土壤生态系统的影响”等方面的研究情况。此外，还对“鉴定外源基因及其表达产物存在的方法”进行了简要探讨。

The Transfer of Foreign Genes and Its Expression Products in Genetically Modified Crops

It has been very important to understand thoroughly potential ecological risk of genetically modified crops (GMCs) with the recent increase of commercial use of GMCs. The likelihood of transgenes dispersal from GMCs to the related wild species, the tolerance of insect to insect\|resistant GMCs and the potential impacts of GMCs on biodiversity had been extensively investigated. This article summarized several possible characteristics of the transfer of foreign genes and their expression products in GMCs: (i) Gene flow from GMCs via pollen dispersal. The distance of pollen flow is determined not only by the biological properties of pollen of different species, but also by natural surroundings; (ii) Spontaneous hybridizations between GMCs and other closely related wild species, which may result in creating super\|weeds; (iii) The fate and consequences of foreign genes and proteins of GMCs in soil micro\|ecosystem. It has been demonstrated that foreign genes or proteins of GMCs can survive for a long time in soils. It has also been shown that Bt plants can secrete Bt toxin from root throughout the entire growth stages, and these toxins can be released from residual materials of GMCs and can be deposited into soils after harvesting. It was suggested that Bt plants may impact the environment, for example, producing toxins to non\|target microorganisms in soils and forcing the evolution of toxin\|resistant target species; (iv) Gene flow via food chains that may influence the biodiversity of nature, such as the effect of GM Bt crops on predators or parasites. Finally, the identification methods of the existence of transgenes and their expressing products were also briefly discussed.