학술논문
A 13C isotope labeling method for the measurement of lignin metabolic flux in Arabidopsis stems
Document Type
Report
Author
Source
Plant Methods. June 23, 2018, Vol. 14 Issue 1
Subject
Language
English
ISSN
1746-4811
Abstract
Author(s): Peng Wang[sup.1] , Longyun Guo[sup.1] , Rohit Jaini[sup.2] , Antje Klempien[sup.1] , Rachel M. McCoy[sup.3] , John A. Morgan[sup.1,2] , Natalia Dudareva[sup.1,4] and Clint Chapple[sup.1,4] Background Metabolic fluxes quantify [...]
Background Metabolic fluxes represent the functional phenotypes of biochemical pathways and are essential to reveal the distribution of precursors among metabolic networks. Although analysis of metabolic fluxes, facilitated by stable isotope labeling and mass spectrometry detection, has been applied in the studies of plant metabolism, we lack experimental measurements for carbon flux towards lignin, one of the most abundant polymers in nature. Results We developed a feeding strategy of excised Arabidopsis stems with .sup.13C labeled phenylalanine (Phe) for the analysis of lignin biosynthetic flux. We optimized the feeding methods and found the stems continued to grow and lignify. Consistent with lignification profiles along the stems, higher levels of phenylpropanoids and activities of lignin biosynthetic enzymes were detected in the base of the stem. In the feeding experiments, .sup.13C labeled Phe was quickly accumulated and used for the synthesis of phenylpropanoid intermediates and lignin. The intermediates displayed two different patterns of labeling kinetics during the feeding period. Analysis of lignin showed rapid incorporation of label into all three subunits in the polymers. Conclusions Our feeding results demonstrate the effectiveness of the stem feeding system and suggest a potential application for the investigations of other aspects in plant metabolism. The supply of exogenous Phe leading to a higher lignin deposition rate indicates the availability of Phe is a determining factor for lignification rates. Keywords: Stable isotope labeling, Stem feeding, Lignin, Phenylpropanoids
Background Metabolic fluxes represent the functional phenotypes of biochemical pathways and are essential to reveal the distribution of precursors among metabolic networks. Although analysis of metabolic fluxes, facilitated by stable isotope labeling and mass spectrometry detection, has been applied in the studies of plant metabolism, we lack experimental measurements for carbon flux towards lignin, one of the most abundant polymers in nature. Results We developed a feeding strategy of excised Arabidopsis stems with .sup.13C labeled phenylalanine (Phe) for the analysis of lignin biosynthetic flux. We optimized the feeding methods and found the stems continued to grow and lignify. Consistent with lignification profiles along the stems, higher levels of phenylpropanoids and activities of lignin biosynthetic enzymes were detected in the base of the stem. In the feeding experiments, .sup.13C labeled Phe was quickly accumulated and used for the synthesis of phenylpropanoid intermediates and lignin. The intermediates displayed two different patterns of labeling kinetics during the feeding period. Analysis of lignin showed rapid incorporation of label into all three subunits in the polymers. Conclusions Our feeding results demonstrate the effectiveness of the stem feeding system and suggest a potential application for the investigations of other aspects in plant metabolism. The supply of exogenous Phe leading to a higher lignin deposition rate indicates the availability of Phe is a determining factor for lignification rates. Keywords: Stable isotope labeling, Stem feeding, Lignin, Phenylpropanoids