铝胁迫对人参根系酚类物质代谢途径的调控机理研究

Obstacles of continuous cropping have been proved to be one of the most important limitations of ginseng cultivation. The increase of aluminum (Al) content on acid soils and allelopathy caused by phenolic compounds in ginseng are two of the main factors that cause obstacles of continuous cropping. The crop yield and growth on acid soils is mainly limited by aluminum toxicity. As one of the most important components of allelopathy, phenolic compounds play an important role on aluminum tolerance in some plants. However, it is still unclear about the relationships between aluminum toxicity and the metabolic mechanism of phenolic compounds produced by ginseng on acid soils. In our project, the metabolic profiles combined with liquid chromatography and mass spectrometry are used to study the different metabolites changes in ginseng roots under Al stress, thereby building the metabolic network diagram. By bioinformatic analysis, we want to find aluminum stress-related phenolic compounds. Combined with the content of these phenolic compounds, synthetic pathways related enzyme activity and gene expression, we will clarify the regulatory mechanism of aluminum stress on phenolic metabolism of ginseng roots, and further to provide the new information on aluminum tolerance mechanisms in ginseng. Meanwhile it plays an important role to reveal the cause of continuous cropping obstacle .The results in this study showed important scientific significance and economic value, could provide the soil amelioration of ginseng and also would enrich the theoretical understanding of continuous cropping obstacles in ginseng (Panax ginseng C.A. Meye). .

人参连作障碍严重制约了人参产业的可持续发展，连作障碍机理研究已成为该领域的热点。参地土壤酸化和人参化感作用是连作障碍问题的重要影响因子，铝毒是酸性土壤中限制植物生长的主要因素之一。酚类物质既是化感作用的重要成分，同时在植物耐铝性上也具有关键作用。然而参地土壤酸化人参受铝毒害与其酚类物质代谢的关系尚不清楚。项目组通过代谢组学中液相色谱、质谱（LC-MS/MS）联用的技术手段，研究铝胁迫下人参根系差异代谢物的变化，构建代谢网络图。通过生物信息学分析，探究与铝胁迫相关的主要酚类物质，进一步结合主要酚类物质含量、代谢途径关键酶的活性、基因表达水平，阐明响应铝胁迫的酚类物质代谢的调控机制。进而为研究人参耐铝机制提供新的依据，同时对于揭示连作障碍的成因具有重要作用。该项目不仅可为参地土壤改良提供理论依据，还可丰富对人参连作障碍的理论认识，具有重要的科学意义和经济价值。

铝毒是酸性土壤上限制植物生长的主要因子之一，酚类物质的合成与分泌在植物耐铝性中起着重要的作用。人参为我国名贵的中药材，它含有的次生代谢物如酚酸和皂苷类物质等不仅是重要的营养物质，而且作为化感物质是导致药用植物连作障碍形成的主要原因之一。本项目以东北地区多年生药用植物-人参为研究对象，利用水培试验，通过测定一系列生理生化指标，研究酸性条件下铝胁迫对人参生物量、矿质营养元素吸收和根系活力等的影响，阐明了人参对铝胁迫的生理响应。进一步利用高通量测序 (llumina HiSeq)和代谢组学(LC-MS/MS)技术分析了铝胁迫下人参根系转录和代谢的变化。本项目研究表明铝胁迫下人参根系酚类物质尤其是香豆酸含量显著增加，同时筛选出铝胁迫24h前后表达差异在2倍以上的转录本1255个，上调648个和下调607个差异基因。初生代谢物(葡萄糖-6-磷酸、肌醇-磷酸)显著减少，而人参根系中酚类物质包括肉桂酸、香豆酸、苯甲酸等含量显著增加。本项目明确了铝胁迫诱导人参根系酚类物质代谢的生理与分子机制，为选育适应酸性土壤上生长的人参新品种提供科学理论依据。