Comparison of salt stress resistance genes in transgenic Arabidopsis thaliana indicates that extent of transcriptomic change may not predict secondary phenotypic or fitness effects
Comparison of salt stress resistance genes in transgenic Arabidopsis thaliana indicates that extent of transcriptomic change may not predict secondary phenotypic or fitness effects
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DOI：
10.1111/j.1467-7652.2011.00661.x
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发表时间：
2012-04-01
影响因子：
13.8
通讯作者：
Grumet, Rebecca
中科院分区：
文献类型：
--
作者：
Chan, Zhulong;Bigelow, Patrick J.;Grumet, Rebecca
工程非生物抗逆性是提高农业生产力的重要目标。然而，人们对转基因作物可能产生的生态影响感到担忧。与第一波转基因作物不同，许多非生物抗逆基因可以引发复杂的下游变化。转录组分析已经被建议作为一种全面的、非靶向的方法来检查次要影响。我们通过三种不同的机制比较了基因结构性表达的表型和转录效应：转录因子CBF3/DREB1a；代谢基因M6PR，用于甘露醇生物合成；以及Na+/H+逆向转运蛋白SOS1。将转CBF3、M6PR和SOS1基因的拟南芥分别在生长箱、温室和大田中种植。在无盐条件下，M6PR和SOS1品系表现与野生型相当；CBF3品系表现出先前报道的矮化。当在生长室中受到100 mM的氯化钠时，所有这三种转基因都具有适应性优势。通过Affymetrix微阵列分析，CBF3和M6PR影响了许多非生物胁迫相关基因的转录。M6PR还修饰了生物应激和氧化应激基因的表达。SOS1在无盐条件下的转录效应较小，主要局限于氧化还原相关基因。然而，转录组变化的程度与对生长和生殖的影响无关。因此，全球转录组差异的大小可能不能预测环境和选择影响适合性的表型差异。这些观察结果对在风险评估的背景下解释转录组分析有意义，并强调了在表型背景下进行评估的重要性。
Engineered abiotic stress resistance is an important target for increasing agricultural productivity. There are concerns, however, regarding possible ecological impacts of transgenic crops. In contrast to the first wave of transgenic crops, many abiotic stress resistance genes can initiate complex downstream changes. Transcriptome profiling has been suggested as a comprehensive non-targeted approach to examine the secondary effects. We compared phenotypic and transcriptomic effects of constitutive expression of genes intended to confer salt stress tolerance by three different mechanisms: a transcription factor, CBF3/DREB1a; a metabolic gene, M6PR, for mannitol biosynthesis; and the Na+/H+ antiporter, SOS1. Transgenic CBF3, M6PR and SOS1 Arabidopsis thaliana were grown together in the growth chamber, greenhouse and field. In the absence of salt, M6PR and SOS1 lines performed comparably with wild type; CBF3 lines exhibited dwarfing as reported previously. All three transgenes conferred fitness advantage when subjected to 100 mm NaCl in the growth chamber. CBF3 and M6PR affected transcription of numerous abiotic stress-related genes as measured by Affymetrix microarray analysis. M6PR additionally modified expression of biotic stress and oxidative stress genes. Transcriptional effects of SOS1 in the absence of salt were smaller and primarily limited to redox-related genes. The extent of transcriptome change, however, did not correlate with the effects on growth and reproduction. Thus, the magnitude of global transcriptome differences may not predict phenotypic differences upon which environment and selection act to influence fitness. These observations have implications for interpretation of transcriptome analyses in the context of risk assessment and emphasize the importance of evaluation within a phenotypic context.