Research progress on the impacts of transgenic resistant plants on pollinating bees
转基因植物对传粉蜂类影响的研究进展

With the commercial planting of transgenic plants on a large scale, their impacts on non-target organisms have become an important part of risk assessment of transgenic organisms. The flowers of many transgenic plants are phanerogams that require bees for pollination. Some transgenic plants do not need bee pollination but are important food sources for bees. Transgenic plants with resistance traits may have direct or indirect effects on bees. Direct effects may arise upon ingestion of transgene products (proteins) if they are expressed in pollen or nectar. Methodologies to test chemical pesticides are used to evaluate the direct effects. Many studies have been conducted on the impacts of purified transgene product ingestion on honey bees (Apis mellifera) and bumblebees (Bombus terrestris). The action mechanisms of several transgene products, such as Bt, protease inhibitor, chitinase and glucanase, are discussed. Indirect effects may occur if plant transformation results in unexpected changes in the plant's phenotype, especially the changes in flower phenotype. Tests with whole transgenic plants have been conducted to assess the indirect effects. The indices measured include bee gut physiology, food consumption, olfactory learning behavior, oral toxicity and longevity. Most tests have been conducted in the laboratory with individual larvae or adult bees. There have also been some tests with colonies under containment and observations of bee foraging on transgenic plants and these are summarised. The results so far suggest that whether transgenic plants would have impacts on pollinating bees and the extent of the impacts depend largely on the biological characteristics of the transgenic plants, the traits of transgene proteins expressed, and the expression of transgene proteins in the parts of the transgenic plants ingested by bees. Generally, proteins such as lepidopteran-specific Bt toxins and glucan-degrading enzymes have no effects on bees. Proteins that target more general aspects of insect biology, such as protease inhibitors (PI) or chitinases, have been demonstrated to have some adverse impacts on bees. The dosage of transgene products ingested by the bee will determine the extent of such effects. However, it has been difficult to analyze and compare different results and to reach a definite conclusion, because different methods were adopted in these studies. Technical standards for evaluating the impacts of transgenic plants on bees need to be developed and refined.