Tea Science Research Institute, College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
Int J Biol Macromol. 2021 May 15;179:485-499. doi: 10.1016/j.ijbiomac.2021.03.025. Epub 2021 Mar 5.
Melatonin (MT) is a bioactive molecule that can regulate various developmental processes. Changes in lignin content play important roles in plant growth and development. Herein, quantitative analysis and histochemical staining showed that lignin content significantly increased over time, and melatonin treatment triggered the lignification at 8 and 16 d in tea leaves. The POD activity participated in lignin formation had also been significantly improved. The effect of melatonin on the increase of lignin content was attenuation over time. Sequencing results based on transcriptome at 8 and 16 d showed that 5273 and 3019 differentially expressed genes (DEGs) were identified in CK1 vs. MT1 and CK2 vs. MT2, respectively. A total of 67 DEGs were annotated to lignin biosynthesis, and 38 and 9 genes were significantly up-regulated under melatonin treatment, respectively. Some transcription factor genes such as MYB were also identified among the two pairwise comparisons, which might relate to lignin metabolism. Melatonin increased the degree of lignification in tea leaves by modifying the enzyme genes expression involved in lignin synthesis pathway. These results provide a reference for further study on the molecular mechanism of the dynamic changes of lignin content induced by melatonin treatment in tea plants.
褪黑素（MT）是一种具有生物活性的分子，可调节各种发育过程。木质素含量的变化在植物生长和发育中起着重要作用。本文通过定量分析和组织化学染色表明，木质素含量随时间显著增加，褪黑素处理在 8 和 16 d 时触发了茶树的木质化。参与木质素形成的过氧化物酶（POD）活性也显著提高。褪黑素对木质素含量增加的影响随时间的推移而减弱。基于 8 和 16 d 的转录组测序结果显示，在 CK1 与 MT1 和 CK2 与 MT2 之间分别鉴定出 5273 和 3019 个差异表达基因（DEGs）。共有 67 个 DEGs 被注释为木质素生物合成，分别有 38 个和 9 个基因在褪黑素处理下显著上调。在这两个两两比较中还鉴定到了一些转录因子基因，如 MYB，它们可能与木质素代谢有关。褪黑素通过修饰参与木质素合成途径的酶基因表达来增加茶树叶片的木质化程度。这些结果为进一步研究褪黑素处理诱导茶树木质素含量动态变化的分子机制提供了参考。
