College of Horticulture, Sichuan Agricultural University, Chengdu 611130, China.
Int J Mol Sci. 2023 Jan 12;24(2):1539. doi: 10.3390/ijms24021539.
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 , , , , , , , and related enzyme activity regulation genes. The expression levels of , , and genes were significantly decreased under shading treatment, while the expression levels of and genes exhibited no significant difference with increased shading. The downregulation of , genes and the decrease in 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.
芦笋属于百合科，具有重要的经济和药用价值。木质素在细胞壁结构完整性、茎强度、水分运输、机械支撑和植物抵御病原体方面起着至关重要的作用。在这项研究中，使用了各种生物方法来研究遮荫对芦笋木质素积累途径的作用机制。生理结果表明，遮荫显著降低了茎直径和细胞壁木质素含量。微观结构观察表明，遮荫减少了维管束和木质部面积，导致木质素含量降低，从而降低了芦笋的木质化程度。肉桂酸、咖啡酸、阿魏酸和丁香醇是木质素合成过程中的关键中间代谢物。代谢组学分析表明，遮荫显著降低了肉桂酸、咖啡酸、阿魏酸和丁香醇的含量。转录组分析确定了 37 个与木质素相关的差异表达基因，包括、、、、、、和相关酶活性调节基因。在遮荫处理下，基因的表达水平显著降低，而基因的表达水平则没有明显差异，随着遮荫程度的增加而增加。基因的下调和基因表达水平的降低抑制了遮荫处理下相应酶的活性，导致下游咖啡酸、阿魏酸、丁香醇、绿原酸和松柏醇含量降低。遮荫导致上游肉桂酸含量显著下降，也导致下游代谢物减少，芦笋木质素含量降低。本研究通过转录组和代谢组分析揭示了遮荫处理下芦笋木质素的关键调控基因和代谢物。本研究为进一步了解木质素生物合成和相关基因的相互作用机制提供了参考。
