A Joint Transcriptomic and Metabolomic Analysis Reveals the Regulation of Shading on Lignin Biosynthesis in Asparagus

Asparagus belongs to the Liliaceae family and has important economic and pharmacological value. Lignin plays a crucial role in cell wall structural integrity, stem strength, water transport, mechanical support and plant resistance to pathogens. In this study, various biological methods were used to...

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Bibliographic Details
Main Authors: Junying Ma, Xiaoyan Li, Maolin He, Yanwen Li, Wei Lu, Mengyao Li, Bo Sun, Yangxia Zheng
Format: Article
Language:English
Published: MDPI AG 2023-01-01
Series:International Journal of Molecular Sciences
Subjects:
Online Access:https://www.mdpi.com/1422-0067/24/2/1539
Description
Summary:Asparagus belongs to the Liliaceae family and has important economic and pharmacological value. Lignin plays a crucial role in cell wall structural integrity, stem strength, water transport, mechanical support and plant resistance to pathogens. In this study, various biological methods were used to study the mechanism of shading on the asparagus lignin accumulation pathway. The physiological results showed that shading significantly reduced stem diameter and cell wall lignin content. Microstructure observation showed that shading reduced the number of vascular bundles and xylem area, resulting in decreased lignin content, and thus reducing the lignification of asparagus. Cinnamic acid, caffeic acid, ferulic acid and sinapyl alcohol are crucial intermediate metabolites in the process of lignin synthesis. Metabolomic profiling showed that shading significantly reduced the contents of cinnamic acid, caffeic acid, ferulic acid and sinapyl alcohol. Transcriptome profiling identified 37 differentially expressed genes related to lignin, including <i>PAL</i>, <i>C4H</i>, <i>4CL</i>, <i>CAD</i>, <i>CCR</i>, <i>POD</i>, <i>CCoAOMT</i>, and <i>F5H</i> related enzyme activity regulation genes. The expression levels of <i>POD</i>, <i>CCoAOMT</i>, and <i>CCR</i> genes were significantly decreased under shading treatment, while the expression levels of <i>CAD</i> and <i>F5H</i> genes exhibited no significant difference with increased shading. The downregulation of <i>POD</i>, <i>CCoAOMT</i> genes and the decrease in <i>CCR</i> gene expression levels inhibited the activities of the corresponding enzymes under shading treatment, resulting in decreased downstream content of caffeic acid, ferulic acid, sinaperol, chlorogenic acid and coniferin. A significant decrease in upstream cinnamic acid content was observed with shading, which also led to decreased downstream metabolites and reduced asparagus lignin content. In this study, transcriptomic and metabolomic analysis revealed the key regulatory genes and metabolites of asparagus lignin under shading treatment. This study provides a reference for further understanding the mechanism of lignin biosynthesis and the interaction of related genes.
ISSN:1661-6596
1422-0067