Shi Yunsu, Wang Tianyu, Li Yu, Darmency Henri
Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Genetics. 2008 Oct;180(2):969-75. doi: 10.1534/genetics.108.092809. Epub 2008 Sep 9.
Developing genetically modified crop plants that are biologically contained could reduce significantly the potential spread of transgenes to conventional and organic crop plants and to wild or weedy relatives. Among several strategies, the hereditary mode of transmission of transgenes, whether dominant, recessive, or maternal, could play a major role in interspecific gene flow. Here we report on the gene flow between foxtail millet (Setaria italica), an autogamous crop, and its weedy relative, S. viridis, growing within or beside fields containing the three kinds of inherited herbicide resistance. Over the 6-year study, in the absence of herbicide selection, the maternal chloroplast-inherited resistance was observed at a 2 x 10(-6) frequency in the weed populations. Resistant weed plants were observed 60 times as often, at 1.2 x 10(-4) in the case of the nuclear recessive resistance, and 190 times as often, at 3.9 x 10(-4) in the case of the dominant resistance. Because the recessive gene was not expressed in the first-generation hybrids, it should be more effective than dominant genes in reducing gene flow under normal agricultural conditions where herbicides are sprayed because interspecific hybrids cannot gain from beneficial genes.
培育具有生物遏制特性的转基因作物能够显著降低转基因向常规作物、有机作物以及野生或杂草近缘种扩散的可能性。在多种策略中，转基因的遗传传递模式，无论是显性、隐性还是母系遗传，都可能在种间基因流动中发挥主要作用。在此，我们报告了自花授粉作物谷子（Setaria italica）与其杂草近缘种绿色狗尾草（S. viridis）之间的基因流动情况，绿色狗尾草生长在含有三种遗传除草剂抗性的农田内部或周边。在为期6年的研究中，在没有除草剂选择的情况下，杂草种群中母系叶绿体遗传抗性的出现频率为2×10⁻⁶。抗性杂草植株出现的频率在核隐性抗性情况下为1.2×10⁻⁴，是前者的60倍，在显性抗性情况下为3.9×10⁻⁴，是前者的190倍。由于隐性基因在第一代杂种中不表达，在正常喷施除草剂的农业条件下，它在减少基因流动方面应该比显性基因更有效，因为种间杂种无法从有益基因中获益。
