Huang Shuai, Kang Xiaoru, Fu Rumeng, Zheng Longyan, Li Peijun, Tang Fengjuan, Chao Nan, Liu Li
Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212100, China.
Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212100, China.
Plants (Basel). 2024 Dec 16;13(24):3512. doi: 10.3390/plants13243512.
Mulberry ( L.) is a significant economic tree species in China. The lignin component serves as a critical limiting factor that impacts both the forage quality and the conversion efficiency of mulberry biomass into biofuel. Cinnamoyl CoA reductase (CCR; EC 1.21.1.44) and cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.95) are the key enzymes that catalyze the final two reductive steps in the biosynthesis of monolignols. In this study, we conducted a comprehensive functional analysis to validate the predominant genes involved in monolignol biosynthesis. In this study, we initially validated the predominant genes implicated in monolignol biosynthesis through an extensive functional analysis. Phylogenetic analysis, tissue-specific expression profiling and enzymatic assays indicated that is the authentic CCR involved in lignin biosynthesis. Furthermore, the expression level of exhibited a significant positive correlation with lignin content, and the down-regulation of via virus-induced gene silencing resulted in altered lignin content in mulberry. The down-regulation of and both individually and concurrently, exhibited markedly different effects on lignin content and mulberry growth. Specifically, the simultaneous down-regulation of and significantly altered lignin content in mulberry, resulting in dwarfism of the plants. Conversely, the down-regulation of alone not only decreased lignin content but also led to an increase in biomass. These findings offer compelling evidence elucidating the roles of in mulberry and identify specific target genes, thereby providing a crucial foundation for the genetic modification of lignin biosynthesis.
桑（L.）是中国重要的经济树种。木质素成分是影响桑饲料质量和桑生物质转化为生物燃料效率的关键限制因素。肉桂酰辅酶A还原酶（CCR；EC 1.21.1.44）和肉桂醇脱氢酶（CAD；EC 1.1.1.95）是催化单木质醇生物合成中最后两个还原步骤的关键酶。在本研究中，我们进行了全面的功能分析，以验证参与单木质醇生物合成的主要基因。在本研究中，我们最初通过广泛的功能分析验证了参与单木质醇生物合成的主要基因。系统发育分析、组织特异性表达谱分析和酶活性测定表明，[此处原文缺失具体基因名称]是参与木质素生物合成的确切CCR。此外，[此处原文缺失具体基因名称]的表达水平与木质素含量呈显著正相关，通过病毒诱导基因沉默下调[此处原文缺失具体基因名称]导致桑中木质素含量改变。单独或同时下调[此处原文缺失具体基因名称]和[此处原文缺失具体基因名称]对木质素含量和桑生长表现出明显不同的影响。具体而言，同时下调[此处原文缺失具体基因名称]和[此处原文缺失具体基因名称]显著改变了桑中的木质素含量，导致植株矮化。相反，单独下调[此处原文缺失具体基因名称]不仅降低了木质素含量，还导致生物量增加。这些发现为阐明[此处原文缺失具体基因名称]在桑中的作用提供了有力证据，并鉴定了特定的靶基因，从而为木质素生物合成的遗传修饰提供了关键基础。
