Yang Jing, Song Jiaxing, Feng Yueyan, Cao Yuman, Fu Bingzhe, Zhang Zhiqiang, Ma Nan, Li Qian, Hu Tianming, Wang Yafang, Yang Peizhi
College of Grassland Agriculture, Northwest A&F University, Yangling 712100, China.
College of Agriculture, Ningxia University, Yinchuan 750021, China.
Int J Biol Macromol. 2023 Aug 15;246:125501. doi: 10.1016/j.ijbiomac.2023.125501. Epub 2023 Jun 20.
Alfalfa is an important forage crop. Yield and quality are frequently threatened by extreme environments such as drought and salt stress. As a component of the cell wall, lignin plays an important role in the abiotic stress response, the mechanisms of which have not been well clarified. In this study, we combined physiological, transcriptional, and metabolic analyses to reveal the changes in lignin content in alfalfa under mannitol-induced osmotic stress. Osmotic stress enhanced lignin accumulation by increasing G and S units, which was associated with increases in enzyme activities and decreases in 8 intermediate metabolites. Upon combined analysis of the transcriptome and metabolome, we identified five key structural genes and several coexpressed transcription factors, such as MYB and WRKY, which may play a core role in regulating lignin content and composition under osmotic stress. In addition, lignin synthesis was positively regulated by ABA but negatively regulated by ethylene under osmotic stress. These results provide new insight into the regulatory mechanism of lignin synthesis under abiotic stress.
紫花苜蓿是一种重要的饲料作物。产量和品质经常受到干旱和盐胁迫等极端环境的威胁。作为细胞壁的组成部分，木质素在非生物胁迫响应中发挥着重要作用，但其机制尚未得到充分阐明。在本研究中，我们结合生理、转录和代谢分析，揭示了甘露醇诱导的渗透胁迫下紫花苜蓿木质素含量的变化。渗透胁迫通过增加G和S单元来增强木质素积累，这与酶活性的增加和8种中间代谢产物的减少有关。通过对转录组和代谢组的联合分析，我们鉴定出5个关键结构基因和几个共表达的转录因子，如MYB和WRKY，它们可能在渗透胁迫下调节木质素含量和组成中起核心作用。此外，在渗透胁迫下，木质素合成受到脱落酸的正调控，但受到乙烯的负调控。这些结果为非生物胁迫下木质素合成的调控机制提供了新的见解。
