单一乙酰度壳寡糖单体的构建及诱导植物抗盐研究

Chitosan can be obtained from wastes of aquatic product such as shells of crab and shrimp. Chitooligosaccharides, the degraded product of chitsan, is a safe natural amino oligosaccharides of abundant resources. Recently, chitooligosaccharides has attracted wide attention as exogenous activator in inducing plant salt resistance. However, previous studies on inducing plant salt resistance activities of chitooligosaccharides were mostly performed using oligomers mixtures with different molecular weights and various degrees of acetyltion. Which chitooligosaccharides molecule is the function unit playing a leading role in inducing plant salt resistance? And what is the structure-activity relationship? These problems remain unknown. Based on our previous work, this project will prepare single chitooligosaccharides series with identical degree of acetylation by large-scale chromatographic separation and selective N-acetylation reaction. Subsequently, the induction of plant salt resistance by chitooligosaccharides will be performed in the model plant, Arabidopsis thaliana. The physiological effect of single chitooligossacchrides on Arabidopsis thaliana under salt stress will be investigated, including the indexes related to membrane protection, osmoregulation, antioxidant enzymes and photosynthesis, which will clarify the key structural characteristics of chitooligosaccharides inducing plant salt resistance. Furthermore, the regulation of SOS1and rd29A genes expression related to salt resistance in Arabidopsis thaliana induced by single chitooligosaccharides will also be discussed to preliminarily reveal the molecular mode of action in eliciting plant salt resistance. This project is expected to provide theoretical basis for the development of high-efficient plant salt-resistance inducer of chitooligosaccharides. It has important significance in achieving high-valued utilization of wastes of aquatic product and promoting the potential of crop production in saline-alkali soil.

壳聚糖可由虾、蟹壳等水产品废弃物加工获得，其降解产物壳寡糖是一种安全无毒、含量丰富的天然氨基寡糖。近年来壳寡糖作为外源诱导剂在缓解植物盐害方面引起关注。然而，目前用于诱导活性实验的壳寡糖供试样品，均是一种含有各个分子量和乙酰度寡糖的混合物，壳寡糖诱导植物抗盐的功能单元是几糖？构效关系如何？尚不明确。本课题在前期工作基础上，通过规模化色谱分离和选择性N-乙酰化反应，构建单一乙酰度壳寡糖单体系列；以模式植物拟南芥为研究对象，从质膜保护、渗透调节、抗氧化保护酶系和光合作用评价单一壳寡糖对提高拟南芥抗盐性的生理响应，明确壳寡搪诱导植物抗盐所必需的分子结构特征；研究单一聚合度和乙酰度壳寡糖对拟南芥抗盐基因SOS1和rd29A的调控作用，初步揭露壳寡糖诱导植物抗盐胁迫的分子机制。本项目的实施将为高效壳寡糖植物抗盐诱导剂的研制提供理论依据，对于水产品废弃物的高值化利用和促进盐碱地作物的生产意义重大。

壳聚糖可由虾、蟹壳等水产品废弃物加工获得，其降解产物壳寡糖是一种安全无毒、含量丰富的天然氨基寡糖。近年来壳寡糖作为植物生理调节物质在缓解植物盐害、促进植物生长等方面引起广泛关注。然而，以往用于诱导活性实验的壳寡糖供试样品，均是一种含有各个分子量和乙酰度寡糖的混合物，壳寡糖农用生物活性的功能单元是几糖？构效关系如何？尚不明确。本项目按照计划书的要求，本项目顺利完成了全N-脱乙酰化壳寡糖单体的规模化色谱分离工艺路线，实现了全N-脱乙酰化壳寡糖单体简便快速的规模化色谱制备；同时也建立了单一乙酰度壳寡糖的制备工艺，构建了具有不同N-乙酰基数量的单一聚合度壳六糖系列；并进一步完成了特定乙酰度、单一聚合度壳寡糖在诱导植物抗盐胁迫、调控植物生长、缓解植物受镉离子毒害的活性评价，揭露了壳寡糖在多种农用生物活性的构效关系及相关作用机制；这些研究成果为壳寡糖类物质在生物农肥农药的研发与应用推广提供了重要的理论依据，对于推动水产品高值化利用、加快蓝色经济发展意义重大；本项目实施过程中，已发表SCI 文章9 篇，申请国家发明专利3 项，协助培养博士研究生2名。项目主持人获得2015年山东省技术发明奖二等奖（排名第4）1 项和2016年青岛市科技进步一等奖（排名第7）1 项。