工业大麻适应盐、碱胁迫的分子机制比较研究

Industrial hemp is developing vigorously worldwide for its non-substitutable qualities in environmental protection, health care, multi-uses and great economic benefits. China is the largest producer of industrial hemp, with half of the world production area. There is as much as about 100 million hectares of salinized soil and fast increasing amount of secondary salinized soil in China, salt and alkali therefor have become the most important damage to the crop production. To avoid competition for farmland of the food crops, bast fiber crops are expanding to the non-grain lands such as the salinized land, the mechanisms of salt and alkali tolerance of the crops therefore desperately need much more efforts than ever to study and clarify. Our previous research results suggested that hemp cultivars showed great diversity of tolerance to salt and alkali stresses, and more sensitive to alkali stress, but what and how one cultivar responds to salt and alkali stresses are not yet understood. Consequently, we in the proposal project would like to impose salinity and alkalinity to the cultivar ‘Yunma 1’, the most important industrial hemp cultivar in China bred in Yunnan Province, by using the optimized stress treatment protocols, investigate the parameters of growth nature, morphology and physio-biochemistry, carry out the joint analysis of proteomics, transcriptomics and miRNA scanning data. By which, we could comparatively study the data collected from levels of the plant appearance, gene expression and regulation, as well as the expression products, and preliminarily contemplate the molecular mechanisms and their diversity of the industrial hemp cultivar responding to the salt and alkali stresses, understand the biological reasons why hemp is more sensitive to alkali and hunt the possible genes for stress tolerance. The study results would set up the groundwork for breeding and cultivation of industrial hemp tolerant to abiotic stresses, and provide critical experimental data and basic knowledge for systematically understanding the biological conundrums of plant tolerance to abiotic stresses, which would play an outstanding role in theory and for future application.

工业大麻有不可替代的环保健康、多用途和高效益优势，发展势头日盛。中国的工业大麻面积约占全球的一半。中国有上亿公顷盐碱地，还有大量的次生盐碱化土地，盐碱害已成为作物最主要的非生物逆境。为避免经、粮作物争地，麻类作物向盐碱地等非粮耕地发展，其耐盐、碱机理的研究因此迫在眉睫。我们前期研究的结果提示，大麻品种的耐盐、碱性差异明显且对碱胁迫更敏感，但尚不清楚大麻应对盐、碱胁迫机制的差异性怎样。项目用云南培育国内首推的工业大麻品种‘云麻1号’为材料，使用规范技术进行盐、碱胁迫处理，观测形态和生理差异，应用转录组、蛋白组和miRNA联合分析，从表观、基因表达与调控及表达产物等多层次上比较研究，初步阐释工业大麻应对盐、碱胁迫的适应机制及其差异性，解析大麻对碱性盐更敏感的生物学原因，发掘潜在的耐逆基因，为系统认识植物耐逆性的生物学机理积累重要的试验数据和基本知识，预期成果在理论上和未来应用上均有重要意义。

工业大麻因适应性强、环保健康且用途多样，其产业发展势头旺盛。中国的工业大麻种植面积世界居首，为避免与粮食作物争地并保持优势地位，工业大麻向盐碱地等非耕地转移是其可持续发展之路，因此耐盐、碱机理研究迫在眉睫。也已探知大麻品种对盐、碱害的敏感性不同，但分子机制尚不明确，为此本项目开展了相关研究。为了保证研究结果的可靠性，利用扦插技术繁殖的‘云麻7号’遗传同质性麻苗为供试材料，使用经优化和规范的方法进行盐、碱胁迫处理，在观测麻苗形态特征和理化特性差异基础上，利用小RNA和转录组测序获得了盐、碱胁迫响应的差异表达miRNA和差异表达基因，通过miRNA、转录组和降解组整合分析鉴定到了盐、碱胁迫相关的显著差异表达的靶基因对分别有33和88个，初步构建了工业大麻响应盐、碱胁迫的转录调控网络，筛选出7个候选基因，并利用定量分析确认了它们的表达特征，其中参与植物激素乙烯和生长素介导的信号通路的PCF5和TIR1与盐、碱胁迫共同相关，参与渗透调节的水通道蛋白基因PIP1和MAPK信号转导通路MAPKK1与盐胁迫特异相关，参与细胞氧化还原稳态调控的CSD1、IDS1和GSTU1与碱胁迫特异相关。应用非靶向代谢组和定量蛋白质组技术对应激代谢产物和功能蛋白进行分析，发现麻叶中响应盐、碱胁迫的代谢产物分别有60和221种、功能蛋白35和36个；响应盐胁迫的主要通路除与淀粉和蔗糖代谢有关还涉及了苯丙烷类的生物合成，而与碱胁迫相关的核心通路是异黄酮类化合物的生物合成。综之，本项目从基因转录调控、表达翻译和代谢产物多层面比较分析，发现渗透调节和活性氧清除分别是大麻适应盐、碱逆境的主要机制，且碱引起的氧化损伤可能是大麻对其更为敏感的关键生物学原因。研究结果为大麻乃至其它植物的耐盐、碱遗传改良和种质创新提供了有益信息，亦为系统认识植物适应逆境的生物学机制积累了试验数据，具有重要的理论意义。