Ghassemian Majid, Lutes Jason, Chang Hur-Song, Lange Iris, Chen Wenqiong, Zhu Tong, Wang Xun, Lange B Markus
Torrey Mesa Research Institute, San Diego, CA 92121, USA.
Phytochemistry. 2008 Dec;69(17):2899-911. doi: 10.1016/j.phytochem.2008.09.020. Epub 2008 Nov 12.
Abscisic acid (ABA) has been implicated as a mediator in plant responses to various environmental stresses. To evaluate the transcriptional and metabolic events downstream of ABA perception, Arabidopsis thaliana seedlings were analyzed by transcript and metabolite profiling, and results were integrated, using the recently developed BioPathAt tool, in the context of the biochemical pathways affected by this treatment. Besides the up-regulation of pathways related to the biosynthesis of compatible solutes (raffinose family oligosaccharides and certain amino acids) as a response to ABA treatment, we also observed a down-regulation of numerous genes putatively localized to and possibly involved in the reorganization of cell walls, an association that had not been recognized previously. Metabolite profiling indicated that specific antioxidants, particularly alpha-tocopherol and L-ascorbic acid, were accumulated at higher levels in ABA-treated seedlings compared to appropriate controls. The transcription of genes involved in alpha-tocopherol biosynthesis were coordinately up-regulated and appeared to be integrated into a network of reactions controlling the levels of reactive oxygen species. Based upon the observed gene expression patterns, these redox control mechanisms might involve an ABA-mediated transition of mitochondrial respiration to the alternative, non-phosphorylating respiratory chain mode. The presented data herein provide indirect evidence for crosstalk between metabolic pathways and pathways regulating redox homeostasis as a response to ABA treatment, and allowed us to identify candidate genes for follow-up studies to dissect this interaction at the biochemical and molecular level. Our results also indicate an intricate relationship, at the transcriptional and possibly post-transcriptional levels, between ABA biosynthesis, the xanthophyll cycle, and ascorbic acid recycling.
脱落酸（ABA）被认为是植物对各种环境胁迫作出反应的一种介质。为了评估ABA感知下游的转录和代谢事件，通过转录本和代谢物谱分析对拟南芥幼苗进行了分析，并使用最近开发的BioPathAt工具，在受该处理影响的生化途径背景下整合了结果。除了作为对ABA处理的反应，与相容性溶质（棉子糖家族寡糖和某些氨基酸）生物合成相关的途径上调外，我们还观察到许多可能定位于细胞壁并可能参与细胞壁重组的基因下调，这种关联以前未被认识到。代谢物谱分析表明，与适当的对照相比，特定的抗氧化剂，特别是α-生育酚和L-抗坏血酸，在ABA处理的幼苗中积累水平更高。参与α-生育酚生物合成的基因转录协同上调，似乎整合到一个控制活性氧水平的反应网络中。基于观察到的基因表达模式，这些氧化还原控制机制可能涉及ABA介导的线粒体呼吸向替代的、非磷酸化呼吸链模式的转变。本文提供的数据为代谢途径与调节氧化还原稳态的途径之间的串扰提供了间接证据，作为对ABA处理的反应，并使我们能够识别候选基因，以便后续研究在生化和分子水平上剖析这种相互作用。我们的结果还表明，在转录水平以及可能的转录后水平上，ABA生物合成、叶黄素循环和抗坏血酸循环之间存在复杂的关系。
