植物对多重非生物胁迫的代谢应答及交谈机制研究

Both growth and productivity of plants are adversely affected by various abiotic stress factors, such as drought, salt and high temperature. Abiotic stress in fact is the principal cause of crop reduction world wide. Such changes in growth condition require an adjustment of metabolic pathways and metabolic network in plant, aimed at achieving a new state of homeostasis, in a process that is usually referred to as acclimation. Researches focusing on responses of plants to various abiotic stresses are very important for understanding the resistance genesis. Recently, the high-throughput metabolomics provides a reliable technological platform for clarification of the key component for achieving the state of homeostasis and the metabolic network involving in those abiotic stresses. In this research, we will apply an unprecedented range of complementary metabolomic analytical platforms including quantitative proton NMR spectroscopy (1H-NMR), gas time-of-flight tandem mass spectrometry (GC-TOF-MS), liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC-QTOF-MS), inductively coupled plasma mass spectrometry (ICP-MS) and liquid chromatography coupled to photodiode array detection (HPLC-PDA) to study the metabolic response of plants to different abiotic stresses, such as single stress and multi-stress of drought, salt and high temperature. Especially, we will pay much attention on the potential metabolic cross-talk in the response of plants to different combination stresses that have received almost no attention by now. To gain a deeper insight into the mechanisms involved in metabolic changes, we will analyze our data using different multivariate visual approaches including principal component analysis, clustering, heat map and correlation network. Understanding the mechanism of stress tolerance along with the potential cross-talk involved in multi-stress is important for the studies of ecological response of plants to stress and crop improvement in multi-stress tolerance.

干旱、高盐、高温等非生物胁迫因子严重影响植物的生长繁育过程，是导致全球农业减产的重要因素。在逆境条件下，植物可通过代谢路径调整，重新组织代谢网络而达到新的代谢稳态并获得对逆境的耐受性。研究植物逆境代谢应答机制对于揭示其抗性稳态建成是至关重要的。但传统的研究方法难以澄清植物逆境代谢稳态网络及关键因子，近年来代谢组学的发展为本领域的研究提供了可靠的技术平台。本研究拟采用核磁共振、气相色谱飞行时间质谱、液相色谱串联四极杆飞行时间质谱以及电感耦合等离子体质谱等多种互补的代谢组学分析技术平台，并结合多维可视化的数据深度挖掘策略，对植物在干旱、高盐及高温单一胁迫及相关的双重、三重胁迫等不同方式的非生物胁迫下的代谢应答机制进行整合研究，尤其关注尚鲜有报道的植物响应多重非生物胁迫的可能的代谢交谈机制。这不仅为获取逆境生态学新知识提供了全新思路，而且为未来抗多逆境植物品种的选育提供可能的靶标具有重要意义。

干旱、高盐、高温、低温及阵发性干旱等非生物胁迫因子严重影响作物的生长繁育过程，是导致全球作物减产的重要因素。研究植物逆境代谢应答机制对于揭示植物抗性稳态建成至关重要。本项目通过盆栽实验研究了玉米在不同非生物胁迫方式下的代谢响应特征，相似及相异性；并且筛选出涉及相似相异性的关键代谢物；研究了代谢物全局关联概况及局部代谢网络组分；描述了玉米应答多重非生物胁迫的代谢交谈网络及可能的交谈机制。. 研究结果表明：玉米对干旱和高盐胁迫的代谢响应存在广泛的共同之处，如渗透调节保护剂类物质胆碱等的显著上调。同时，玉米对两种单一胁迫的响应也存在明显的特异性，如苹果酸在干旱胁迫下显著上调而在盐胁迫下则显著下调。胆碱是在干旱、高盐及双重胁迫下均响应明显的代谢物，是可能的干旱与高盐胁迫下代谢交谈的中心代谢物之一，其在双重胁迫下的代谢相关网络中具有27个连接点，与TCA循环、糖代谢和脂肪酸代谢产物广泛相关。高温、干旱双重胁迫与两种单一胁迫下发生明显响应的代谢物存在交叠和特异性。基于糖代谢、氨基酸代谢、脂质代谢3个代谢路径及生理功能方面的分析表明高温干旱双重胁迫是一种不同于单一高温和干旱胁迫的新的胁迫类型。玉米响应高温和低温胁迫的代谢物及代谢路径的变化存在广泛的共性和特异性。这种共性涉及到氨基酸的增加及糖类物质的协同下降，而在不同条件下三羧酸循环、脂肪酸代谢及与莽草酸路径相关的次生代谢则明显不同。玉米可以通过复杂的生长及代谢调节过程来应答连续的周期性水分胁迫。为响应两个循环的周期性水分胁迫，代谢物主要呈现出四种不同的协同变化方式。糖类代谢物及肌醇在二次复水后仍然保持在较高水平，说明在二次复水后玉米叶片仍然需要高水平渗透调节物质来维持细胞的功能。. 上述研究结果将为在日益变化的环境下进行作物高产栽培和育种提供重要依据。其次，依托本项目资助已发表的论文4篇，再投稿件2篇；培养研究生3名，本项目顺利获得了预期研究结果。