Table_1_The Cell Wall Polysaccharides Biosynthesis in Seaweeds: A Molecular Perspective.XLSX

Cell wall polysaccharides (CWPS) of seaweeds play crucial roles in mechanical shear resistance, cell-cell adhesion and the interactions with changeable marine environments. They have diverse applications in food, cosmetics, agriculture, pharmaceuticals and therapeutics. The recent boost of multi-omics sequence analysis has rapidly progressed the mining of presumed genes encoding enzymes involved in CWPS biosynthesis pathways. In this review, we summarize the biosynthetic pathways of alginate, fucoidan, agar, carrageenan and ulvan in seaweeds referred to the literatures on published genomes and biochemical characterization of encoded enzymes. Some transcriptomic data were briefly reported to discuss the correlation between gene expression levels and CWPS contents. Mannuronan C-5 epimerase (MC5E) and carbohydrate sulfotransferase (CST) are crucial enzymes for alginate and sulfated CWPS, respectively. Nonetheless, most CWPS-relevant genes were merely investigated by gene mining and phylogenetic analysis. We offer an integrative view of CWPS biosynthesis from a molecular perspective and discuss about the underlying regulation mechanism. However, a clear understanding of the relationship between chemical structure and bioactivities of CWPS is limited, and reverse genetic manipulation and effective gene editing tools need to be developed in future.

海藻细胞壁多糖（CWPS）在海藻的机械剪切阻力、细胞间粘附以及与变化多端的海洋环境相互作用中扮演着至关重要的角色。它们在食品、化妆品、农业、制药和治疗等领域具有广泛的应用。随着多组学序列分析的蓬勃发展，近期对编码参与CWPS生物合成途径的酶的基因的挖掘取得了迅速进展。在本综述中，我们根据已发表的基因组文献和编码酶的生化特征，总结了海藻中褐藻酸、岩藻糖、琼脂、角叉菜胶和马尾藻多糖的生物合成途径。为了探讨基因表达水平与CWPS含量之间的相关性，简要报道了一些转录组数据。岩藻糖C-5异构酶（MC5E）和碳水化合物磺基转移酶（CST）分别是褐藻酸和硫酸化CWPS的关键酶。尽管如此，大多数与CWPS相关的基因仅通过基因挖掘和系统发育分析进行了研究。我们提供了一个从分子角度对CWPS生物合成进行综合的观点，并讨论了其潜在的调控机制。然而，对CWPS的化学结构与生物活性之间关系的清晰理解仍然有限，未来需要开发反向遗传操作和有效的基因编辑工具。