Using a single transgenic event to infer fitness effects in crop-weed hybrids: a reply to the Letter by Grunewald & Bury (2014)
Using a single transgenic event to infer fitness effects in crop-weed hybrids: a reply to the Letter by Grunewald & Bury (2014)
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DOI：
10.1111/nph.12748
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发表时间：
2014-04-01
期刊：
影响因子：
9.4
通讯作者：
Wang, Wei
中科院分区：
文献类型：
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作者：
Lu, Bao-Rong;Snow, Allison A.;Wang, Wei
Grunewald&Bury(2014；在本期《新植物学家》杂志中，第367-369页)批评了我们最近发表的同行评议论文(Wang等人，2014；在这一期《新植物学家》，第679-683页)，称我们“不必要地伤害了关于转基因作物的敏感辩论”。我们不会在这里集中讨论这个充满政治色彩的话题，但我们确实想要解决我们对转基因作物杂草(水稻和野生稻)杂交的研究中的科学问题。Grunewald和Bury提出，在这些杂交种的EP3作物亲本中，刺激分蘖形成的插入效应比转基因过表达5-烯醇丙酮基莽草酸-3-磷酸合成酶(EPSP)(我们的中心假设)的直接效应更能令人信服地解释我们的结果。在我们的研究中，正如预期的那样，基因工程(GE)分离物比非GE分离物有显著更多的EPSP表达，并产生显著更多的EPSPS酶(Wang等人，2014)。正如后面讨论的那样，我们怀疑插入效应能否解释我们的转基因株系在提高繁殖力、叶片中更大的色氨酸浓度以及其他性状方面明显和显著的增加，这些特征可以用转基因Esps的过度表达及其在莽草酸途径中的关键作用来更简明地解释(Wang等人，2014)。色氨酸是通过这一途径产生的，是生长激素(生长素)和次生代谢产物的前体，在植物防御中发挥作用(例如Maeda&Dudareva，2012)。色氨酸只是莽草酸途径的众多产物之一，它可以占植物生物量的35%(例如Franz等人，1997)。回顾一下，我们的两个作物亲本水稻系(图1)是自交系明恢86和一个转基因水稻品系(EP3)，后者是通过转化明恢86获得的(Su等人，2008；Lu等人，2014(本期《新植物学家》，第363-366页)；Wang等人，2014)。因此，这些品系的不同之处仅在于没有或存在单拷贝插入的转基因构建体，以及可能的未知转化副作用。Su等人(2008)和我们的支持信息表S1(Wang等人，2014)表明，EP3的每株分蘖和穗数显著高于明辉-86。这表明在EP3中转基因对植物的生长和繁殖有直接的影响。我们不明白为什么Grunewald和Bury甚至不承认他们在信中的选项(2)中的这一解释。相反，他们假设EP3的优越性能是由于一个链接的序列
Grunewald & Bury (2014; in this issue ofNew Phytologist, pp. 367–369) criticize our recent peer-reviewed paper (Wang et al., 2014; in this issue of New Phytologist, pp. 679–683), stating that we ‘unnecessarily harm the sensitive debate on GM crops.’We will not focus on this politically charged topic here, but we do want to address scientific questions about our study of transgenic crop–weed (Oryza sativa and O. sativa f. spontanea) hybrids of rice. Grunewald and Bury propose that an insertion effect that stimulated tiller formation in the EP3 crop parent of these hybrids offers a more convincing explanation of our results than direct effects of a transgene for over-expressing 5-enolpyruvoylshikimate-3-phosphate synthase (epsps)(our central hypothesis). In our study, the genetically engineered (GE) segregants had significantly greater expression of epsps and produced significantly greater amounts of the enzyme of EPSPS than the non-GE segregants, as expected (Wang et al., 2014). As discussed later, we doubt that an insertion effect could account for the clear and significant increases in our transgenic lines in terms of enhanced fecundity, greater tryptophan concentrations in leaves, and other traits, which are more parsimoniously explained by transgenic over-expression of epsps and its key role in the shikimic acid pathway (Wang et al., 2014). Tryptophan is produced by this pathway and is a precursor of growth hormones (auxin) and secondary metabolites that play a role in plant defense (eg Maeda & Dudareva, 2012). Tryptophan is just one of many products of the shikimic acid pathway, which can account for as much as 35% of a plant’s biomass (eg Franz et al., 1997).To review, our two crop parental rice lines (Fig. 1) were the inbred line Minghui-86 and a transgenic rice line (EP3), which was obtained by transforming Minghui-86 (Su et al., 2008; Lu et al., 2014 (this issue of New Phytologist, pp. 363–366); Wang et al., 2014). Thus, these lines differed only in the absence or presence of a single-copy insertion of the transgenic construct and possible unknown side-effects of transformation. Su et al.(2008) and our Supporting Information Table S1 (Wang et al., 2014) showed that EP3 produced significantly more tillers and panicles per plant than Minghui-86. This suggests a direct effect of the transgene on plant growth and reproduction in EP3. We do not understand why Grunewald and Bury do not even acknowledge this explanation under ‘option (2)’of their letter. Instead, they assume that the superior performance of EP3 was due to a linked sequence that