Metabolomic analysis with GC-MS to reveal potential metabolites and biological pathways involved in Pb &Cd stress response of radish roots.

Yan Wang,Liwang Liu,Xiaochuan Sun,Xianwen Zhu,Hong Shen,Juanjuan Wang,Liang Xu,Ronghua Wang,Wei Liu

doi:10.1038/srep18296

Abstract

The radish (Raphanus sativus L.) is an important root vegetable crop. In this study, the metabolite profiling analysis of radish roots exposed to lead (Pb) and cadmium (Cd) stresses has been performed using gas chromatography-mass spectrometry (GC-MS). The score plots of principal component analysis (PCA) and partial least squares-discriminate analysis (PLS-DA) showed clear discrimination between control and Pb- or Cd-treated samples. The metabolic profiling indicated Pb or Cd stress could cause large metabolite alteration mainly on sugars, amino acids and organic acids. Furthermore, an integrated analysis of the effects of Pb or Cd stress was performed on the levels of metabolites and gene transcripts from our previous transcriptome work in radish roots. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of integration data demonstrated that exposure of radish to Pb stress resulted in profound biochemical changes including carbohydrate metabolism, energy metabolism and glutathione metabolism, while the treatment of Cd stress caused significant variations in energy production, amino acid metabolism and oxidative phosphorylation-related pathways. These results would facilitate further dissection of the mechanisms of heavy metal (HM) accumulation/tolerance in plants and the effective management of HM contamination in vegetable crops by genetic manipulation.

Highlights

The arrival of ‘omics’ approaches have been widely used in modern biology aimed at massively characterising the molecular mechanisms of living systems at different levels, which can give a system-wide view of understanding the various layers of the cellular architecture underlying function of biological networks[10,11,12]
There are no reports to investigate the metabolite changes of radish under the heavy metal (HM) exposure using metabolomics technology, which has been regarded as an important research field in the post-genomic area, especially for plant physiological responses to various stresses[34,35,36]
We report a comprehensive analysis of metabolic changes in radish responding to heavy metal (Pb or Cd) stress using a gas chromatography-mass spectrometry (GC-mass spectrometry (MS))-based metabolomics approach

Summary

Introduction

The arrival of ‘omics’ approaches have been widely used in modern biology aimed at massively characterising the molecular mechanisms of living systems at different levels, which can give a system-wide view of understanding the various layers of the cellular architecture underlying function of biological networks[10,11,12]. There has been no report on investigating the metabolite changes in response to HM stress by employing metabolomics technology in radish. To reveal the integrative biochemical networks of the radish in response to Pb or Cd stress, the metabolomic data were integrated with our previous transcriptomic data, which provided a more global view of the molecular and cellular changes elicited by Pb and Cd exposure in radish. This work comprehensively provides the framework for a better understanding of the mechanisms that govern plant cell response to HM-induced stress in radish at a molecular level, and the resulting information would facilitate the effective management of HM contamination in vegetable crops by genetic manipulation

Methods

Results

Conclusion