褪黑素介导的脂质重塑参与盐胁迫下甘薯幼苗离子平衡的调控

发布时间：2018-04-20 21:11

本文选题：褪黑素 + 甘薯　；参考：《江苏师范大学》2017年硕士论文

【摘要】：盐胁迫是影响农作物产量的主要非生物胁迫因子之一。甘薯(Ipomoea batatas[L.]Lam)是世界第七大农作物,也是我国第四大农作物,具有重要经济价值。全面了解不同栽培种甘薯对盐胁迫的响应机制,深入探究栽培种甘薯盐胁迫耐受性的分子生理机制,对培育甘薯耐盐品种以及寻找提高甘薯耐盐性的途径和方法均具有较为重大意义。植物在盐胁迫下的代谢响应与盐耐受性直接相关,很多主要和次生代谢物均参与植物耐盐性的调控过程。本实验室前期非靶标代谢组学研究结果显示褪黑素可能参与甘薯耐盐性的调控。本论文以相对耐盐甘薯品种徐薯22和盐敏感品种徐薯32作为实验材料,研究了褪黑素合成相关代谢物在两种甘薯幼苗盐胁迫响应过程中的动态变化;此外,还研究了外源褪黑素对盐敏感品种徐薯32在盐胁迫下离子平衡和脂质代谢的影响,并探讨了褪黑素调控的脂质代谢重塑与甘薯幼苗离子平衡调控的相关性。具体得到以下结果:(1)盐胁迫下(150 mM NaCl处理15天),两种甘薯幼苗根叶组织褪黑素合成相关中间代谢物以及褪黑素浓度变化具有较大差异。徐薯22根叶组织中色氨酸、色胺、血清素、N-乙酰血清素和褪黑素浓度均在盐胁迫下显著升高,而徐薯32根叶组织中这些代谢物浓度则变化较小,且褪黑素浓度在盐胁迫过程中均显著低于徐薯22。(2)外源褪黑素能够明显降低盐胁迫下徐薯32叶片伤害指标,如电解质外渗率、丙二醛含量等;同时,明显提高叶片的叶绿素含量和相对含水量。(3)外源褪黑素能够提高徐薯32在盐胁迫下的矿质营养(K,Ca,Mg,Mn,Fe,Cu,Se等)水平,并能够显著降低盐离子在叶片中的积累。外源褪黑素提高徐薯32盐胁迫下保K~+能力主要是因为改善了胞内能量水平并促进了质膜H~+-ATPase活性的提高,从而减少了盐胁迫诱导的K~+外流。(4)褪黑素处理明显改变徐薯32叶片脂质组,造成磷脂酸(PA)、磷脂酰胆碱(PC)、磷脂酰肌醇(PI)、二酰甘油(DAG)和单半乳糖二酰甘油(MGDG)丰度明显的增加,三酰甘油(TAG)丰度明显的降低。盐胁迫处理导致徐薯32叶片膜脂含量显著降低,包括PC、磷脂酰乙醇胺(PE)、磷脂酰甘油(PG)、磷脂酰丝氨酸(PS)等磷脂;而储存脂质TAG含量则在盐胁迫下极显著上升。外源褪黑素明显改变徐薯32在盐胁迫下叶片脂质组,这些改变包括完全抑制了盐诱导TAG的积累、增加了PS和PG丰度、降低了MGDG丰度。(5)荧光定量PCR实验结果显示外源褪黑素在盐胁迫下能够上调徐薯32叶片脂肪酶(SDP1)、脂肪酸β-氧化(LACS6/LACS6/ACX1/ACX2/ACX4)、异柠檬酸裂解酶(ICL)和柠檬酸合成酶(CSY2)等基因的表达。(6)脂肪酸β-氧化途径抑制剂DMP处理造成盐胁迫下或盐合并褪黑素处理下徐薯32根叶细胞脂滴大量积累,并降低了根叶组织K~+含量、质膜H~+-ATPase活性和ATP含量;同时根叶组织中Na~+含量显著增加。(7)利用p-CPA抑制内源褪黑素合成导致徐薯22在盐胁迫下根叶细胞中脂滴明显增加;p-CPA处理还导致盐胁迫诱导徐薯22根叶细胞K~+外流幅度明显增大,H~+外流幅度明显降低。综合以上实验证据,本论文发现褪黑素具有促进盐胁迫下甘薯幼苗营养组织TAG分解、脂肪酸β-氧化和能量转换的作用,因此在盐胁迫下内源合成的褪黑素或外源施加褪黑素均能够使根叶细胞维持较好的能量状态,从而驱动质膜H~+-ATPase活性以降低K~+流失并促进Na~+外排,最终实现胞内合适的K~+/Na~+平衡和耐盐性的提升。本论文揭示了褪黑素在植物耐盐性调控中的新作用,并为理解甘薯耐盐性差异的生理及分子机制提供了新思路,也为培育耐盐甘薯新品种奠定了一定的理论基础。
[Abstract]:Salt stress is one of the main abiotic stress factors that affect crop yield. Ipomoea batatas[L.]Lam (sweet potato) is the seventh largest crop in the world, and it is also the fourth largest crop in China. It has important economic value. It is a comprehensive understanding of the response mechanism of sweet potato to salt stress in different cultivated varieties and the deep exploration of the molecular tolerance of salt stress in cultivated sweet potato. Physiological mechanism is of great significance to cultivating salt tolerant varieties and ways and methods to improve salt tolerance of sweet potato. The metabolic response of plants under salt stress is directly related to salt tolerance. Many major and secondary metabolites all participate in the regulation of salt tolerance in plants. The results showed that melatonin may be involved in the regulation of salt tolerance of sweet potato. In this paper, the dynamic changes of melatonin synthesis related metabolites in the salt stress response of two kinds of sweet potato seedlings were studied with relative salt tolerant sweet potato variety Xu tuber 22 and salt sensitive variety Xu 32, and the salt sensitive varieties of melatonin were also studied. The effects of ion balance and lipid metabolism under salt stress, and the correlation between lipid metabolism remodeling and ion balance regulation of sweet potato seedlings under melatonin regulation were discussed. The following results were obtained as follows: (1) the intermediate metabolites and melatonin of melatonin synthesis in root and leaf tissues of two sweet potato seedlings under salt stress (150 mM NaCl treatment for 15 days) The concentrations of tryptophan, tryptamine, serotonin, N- acetyl serotonin and melatonin in the 22 leaf tissues of Xu tuber were significantly increased under salt stress, but the concentrations of these metabolites in the 32 leaf tissues of Xu tuber were smaller, and the concentration of melatonin was significantly lower than that of melatonin in the process of salt stress. The concentration of melatonin was significantly lower than that of 22. (2) melatonin. In addition, the chlorophyll content and the relative water content of the leaves were obviously improved. (3) exogenous melatonin could improve the level of mineral nutrition (K, Ca, Mg, Mn, Fe, Cu, Se, etc.) under salt stress, and could significantly reduce the salt ions in the leaves. The ability of exogenous melatonin to improve the K~+ ability of K~+ under salt stress was mainly due to the improvement of the intracellular energy level and the enhancement of the H~+-ATPase activity of the plasma membrane, thus reducing the K~+ Exodus induced by salt stress. (4) melatonin treatment significantly changed the lipid group of Xu tuber 32 leaves, resulting in phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylcholine muscle. The abundance of alcohol (PI), two acylglycerol (DAG) and monalacose two glycerol (MGDG) was obviously increased, and the abundance of three glycerol (TAG) decreased significantly. Salt stress treatment resulted in a significant decrease in the membrane lipid content of the leaves of the sweet potato 32, including PC, phosphatidyl ethanolamine (PE), phosphatidylglycerol (PG), phosphatidylserine (PS) and other phospholipids, while the storage lipid TAG content was under salt stress. Exogenous melatonin significantly changed the lipid groups of leaves of Xu tuber 32 under salt stress. These changes included completely inhibiting the accumulation of salt induced TAG, increasing the abundance of PS and PG, and reducing the abundance of MGDG. (5) the fluorescence quantitative PCR experiment showed that exogenous melatonin could increase the lipase (SDP1) of vane 32 leaves under salt stress (SDP1). The expression of fatty acid beta oxidation (LACS6/LACS6/ACX1/ACX2/ACX4), ISO citrate lyase (ICL) and citrate synthetase (CSY2). (6) the fatty acid beta oxidation pathway inhibitor DMP treatment resulted in a large accumulation of lipid droplets in 32 leaf cells under salt stress or salt combined with melatonin, and reduced the K~+ content of root leaves and plasma membrane H~+-ATPase. Activity and ATP content, and the content of Na~+ in root leaf tissues increased significantly. (7) the use of p-CPA to inhibit endogenous melatonin synthesis resulted in a significant increase in lipid droplets in root leaf cells under salt stress, and p-CPA treatment also led to salt stress induced K~+ Exodus in 22 leaf cells of tuber significantly, and the amplitude of H~+ Exodus decreased significantly. Comprehensive above experimental evidence It is found that melatonin has the effect of promoting TAG decomposition, fatty acid beta oxidation and energy conversion under salt stress. Therefore, melatonin or exogenous melatonin can maintain a good energy state in root leaf cells under salt stress, thus driving the H~+-ATPase activity of the plasma membrane to reduce the K~+ flow. In this paper, the new role of melatonin in the regulation of salt tolerance in plants has been revealed. This paper provides new ideas for understanding the physiological and molecular mechanisms of salt tolerance differences in sweet potato, and also lays a theoretical foundation for the cultivation of new varieties of salt tolerant sweet potato varieties, and also provides a theoretical basis for the cultivation of salt tolerant sweet potato varieties.

【学位授予单位】：江苏师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S531

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