Key Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo and Rattan Science and Technology, Institute of Gene Science and Industrialization for Bamboo and Rattan Resources, International Center for Bamboo and Rattan, Beijing 100102, China.
Jiangxi Academy of Forestry, Jiangxi Provincial Key Laboratory of Plant Biotechnology, Nanchang 330013, China.
Plant Physiol. 2021 Oct 5;187(2):900-916. doi: 10.1093/plphys/kiab289.
Woody bamboo is environmentally friendly, abundant, and an alternative to conventional timber. Degree of lignification and lignin content and deposition affect timber properties. However, the lignification regulatory network in monocots is poorly understood. To elucidate the regulatory mechanism of lignification in moso bamboo (Phyllostachys edulis), we conducted integrated analyses using transcriptome, small RNA, and degradome sequencing followed by experimental verification. The lignification degree and lignin content increased with increased bamboo shoot height, whereas phenylalanine ammonia-lyase and Laccase activities first increased and then decreased with shoot growth. Moreover, we identified 11,504 differentially expressed genes (DEGs) in different portions of the 13th internodes of different height shoots; most DEGs associated with cell wall and lignin biosynthesis were upregulated, whereas some DEGs related to cell growth were downregulated. We identified a total of 1,502 miRNAs, of which 687 were differentially expressed. Additionally, in silico and degradome analyses indicated that 5,756 genes were targeted by 691 miRNAs. We constructed a regulatory network of lignification, including 11 miRNAs, 22 transcription factors, and 36 enzyme genes, in moso bamboo. Furthermore, PeLAC20 overexpression increased lignin content in transgenic Arabidopsis (Arabidopsis thaliana) plants. Finally, we proposed a reliable miRNA-mediated "MYB-PeLAC20" module for lignin monomer polymerization. Our findings provide definite insights into the genetic regulation of bamboo lignification. In addition to providing a platform for understanding related mechanisms in other monocots, these insights could be used to develop strategies to improve bamboo timber properties.
竹木是一种环保、丰富的材料，可替代传统木材。木质化程度和木质素含量及沉积会影响木材的性质。然而，单子叶植物木质化的调控网络还知之甚少。为了阐明毛竹（Phyllostachys edulis）木质化的调控机制，我们采用转录组、小 RNA 和降解组测序进行了综合分析，并进行了实验验证。木质化程度和木质素含量随竹笋高度的增加而增加，而苯丙氨酸解氨酶和漆酶活性随笋生长先增加后降低。此外，我们在不同高度笋的第 13 节间不同部位鉴定到 11504 个差异表达基因（DEGs）；与细胞壁和木质素生物合成相关的大多数 DEGs 上调，而一些与细胞生长相关的 DEGs 下调。我们共鉴定到 1502 个 miRNA，其中 687 个差异表达。此外，计算机分析和降解组分析表明，5756 个基因被 691 个 miRNA 靶向。我们构建了毛竹木质化的调控网络，包括 11 个 miRNA、22 个转录因子和 36 个酶基因。此外，PeLAC20 的过表达增加了转基因拟南芥（Arabidopsis thaliana）植物的木质素含量。最后，我们提出了一个可靠的 miRNA 介导的“MYB-PeLAC20”模块，用于木质素单体聚合。我们的研究结果为竹木质化的遗传调控提供了明确的见解。除了为理解其他单子叶植物的相关机制提供平台外，这些见解还可以用于开发策略来改善竹材的性质。
