Institute of Biology, Leiden University, P.O. Box 9505, 2300 RA, Leiden, The Netherlands.
Institute of Biochemistry and Biotechnology, University of the Punjab, Quaid-e-Azam campus, P.O Box 54590, Lahore, Pakistan.
Metabolomics. 2018 Jan 31;14(3):25. doi: 10.1007/s11306-018-1317-0.
WRKY proteins belong to a plant-specific class of transcription factors. Seventy-four WKRY genes have been identified in Arabidopsis and many WRKY proteins are known to be involved in responses to stress, especially to biotic stress. They may act either as transcriptional activators or as repressors of genes that play roles in the stress response. A number of studies have proposed the connection of Arabidopsis WRKY transcription factors in induced pathogenesis-related (PR) gene expression, although no direct evidence has been presented for specific WRKY-PR promoter interactions.
We previously identified AtWRKY50 as a transcriptional activator of SAR gene PR1. Although PR1 accumulates to high levels in plants after attack by pathogens, its function is still elusive. Here we investigated the effects of overexpression of several WRKY proteins, including AtWRKY50, on the metabolome of Arabidopsis thaliana.
The influence of overexpression of WRKY proteins on the metabolites of Arabidopsis was investigated by using an NMR spectroscopy-based metabolomic approach. The H NMR data was analysed using the multivariate data analysis methods, such as principal component analysis, hierarchical cluster analysis and partial least square-discriminant analysis.
The results showed that the metabolome of transgenic Arabidopsis seedlings overexpressing AtWRKY50 was different from wild type Arabidopsis and transgenic Arabidopsis overexpressing other WRKY genes. Amongst other metabolites, sinapic acid and 1-O-sinapoyl-β-D-glucose especially appeared to be the most prominent discriminating metabolites, accumulating to levels 2 to 3 times higher in the AtWRKY50 overexpressor lines.
Our results indicate a possible involvement of AtWRKY50 in secondary metabolite production in Arabidopsis, in particular of hydroxycinnamates such as sinapic acid and 1-O-sinapoyl-β-D-glucose.
WRKY 蛋白属于植物特有的一类转录因子。在拟南芥中已鉴定出 74 个 WRKY 基因，许多 WRKY 蛋白被认为参与了应激反应，特别是生物胁迫反应。它们可能作为转录激活因子或基因的抑制剂发挥作用，这些基因在应激反应中发挥作用。许多研究提出了拟南芥 WRKY 转录因子与诱导的病程相关（PR）基因表达的联系，尽管尚未提出特定 WRKY-PR 启动子相互作用的直接证据。
我们之前鉴定出 AtWRKY50 是 SAR 基因 PR1 的转录激活因子。尽管 PR1 在植物受到病原体攻击后会大量积累，但它的功能仍不清楚。在这里，我们研究了过表达几种 WRKY 蛋白，包括 AtWRKY50，对拟南芥代谢组的影响。
采用基于 NMR 光谱的代谢组学方法研究 WRKY 蛋白过表达对拟南芥代谢物的影响。使用主成分分析、层次聚类分析和偏最小二乘判别分析等多元数据分析方法对 H NMR 数据进行分析。
结果表明，过表达 AtWRKY50 的转基因拟南芥幼苗的代谢组与野生型拟南芥和过表达其他 WRKY 基因的转基因拟南芥不同。在其他代谢物中，芥子酸和 1-O-芥子酰基-β-D-葡萄糖尤其似乎是最显著的区分代谢物，在 AtWRKY50 过表达系中积累水平高出 2 到 3 倍。
我们的结果表明，AtWRKY50 可能参与了拟南芥次生代谢产物的产生，特别是芥子酸和 1-O-芥子酰基-β-D-葡萄糖等羟基肉桂酸的产生。
