本文關鍵詞：褪黑素處理對氯化鈉脅迫下黃瓜種子萌發(fā)的影響及其分子機制　出處：《中國農業(yè)大學》2016年博士論文　論文類型：學位論文

  更多相關文章： 黃瓜 種子萌發(fā) 氯化鈉脅迫 褪黑素 植物激素 能量代謝

【摘要】：種子萌發(fā)是高等植物生命周期中一個非常復雜和關鍵的生物學過程,它影響植物的形態(tài)建成和生長發(fā)育。種子萌發(fā)起始于水分吸收,終止于胚根突破種皮露白。當種子吸水后,種子內部開始發(fā)生相應的生理生化反應打破休眠,啟動萌發(fā)。種子萌發(fā)過程中包含蛋白質的合成,轉錄翻譯后修飾,激素的合成與代謝等許多生理生化過程。褪黑素,化學名稱為N-乙�；�-5-甲氧基色胺。褪黑素在植物中也是普遍存在的,但其在植物中的功能研究尚在起步階段。植物除了從環(huán)境中吸收褪黑素以外還可以自身合成褪黑素。外源褪黑素處理能夠提高植物對逆境脅迫的抵御能力。本論文探索了氯化鈉脅迫下外源褪黑素處理對促進黃瓜種子萌發(fā)生理生化變化的影響,同時結合label-free技術從蛋白質組學的調控角度研究了褪黑素調控種子萌發(fā)的分子機制,使褪黑素在種子萌發(fā)過程中的作用更加清晰。主要結果如下：(1)外源褪黑素(1μmol/L)處理能夠明顯促進氯化鈉脅迫下黃瓜種子萌發(fā)。氯化鈉脅迫(150mmol/L)下,黃瓜種子中產生大量活性氧(ROS),羥自由基和過氧化氫都處于較高水平。褪黑素本身是一種抗氧化劑,因此,褪黑素處理能夠清除氯化鈉脅迫產生的多余活性氧,使羥自由基和過氧化氫的含量處于較低水平,膜脂過氧化程度下降,從而保護細胞免于氧化傷害。同時作為一種調控因子,褪黑素通過促進種子內抗氧化酶合成基因CsCu-ZnSOD, CsFe-ZnSOD, CsCAT和CsPOD的表達來提高超氧化物歧化酶(SOD)、過氧化氫酶(CAT)和過氧化物酶(POD)的活性,促進多余活性氧的清除,從而保持體內活性氧平衡。(2)ABA和GA的合成代謝對種子萌發(fā)的影響非常重要。外源褪黑素能夠促進氯化鈉脅迫下黃瓜種子萌發(fā)過程中ABA的分解代謝和GA的合成。在氯化鈉脅迫下,一方面褪黑素通過上調ABA代謝基因CsCYP707A1和CsCYP707A2的表達加速ABA的代謝分解；同時下調ABA的合成基因CsNECD2的表達阻礙ABA的生物合成,使得種子萌發(fā)過程中ABA含量迅速下降,解除ABA對種子萌發(fā)的抑制作用。另一方面,褪黑素還能上調GA合成基因CsGA20ox和CsGA3ox的表達,使種子內GA尤其是HA4的合成增加,緩解氯化鈉脅迫對種子萌發(fā)的抑制作用。(3)氯化鈉脅迫下,褪黑素顯著促進了種子內貯藏物質(球蛋白)代謝和細胞骨架(微管和微絲蛋白)的生成,促進細胞分裂和伸長,進而促進種子萌發(fā)。褪黑素還調控眾多與信號傳導和逆境脅迫相關蛋白,包括14-3-3蛋白,HSP,抗氧化系統酶,泛醌溶酶體蛋白等。以上結果說明,褪黑素能夠調控萌發(fā)過程中種子對氯化鈉脅迫下信號的感知,多余活性氧的清除,脅迫的耐受性和受損蛋白的重新折疊及降解等過程。(4)蛋白質組學數據表明,外源褪黑素能夠參與種子萌發(fā)過程中能量的代謝調控。氯化鈉脅迫下,褪黑素處理加速種子中油脂的降解,降解產物脂肪酸進入乙醛酸循環(huán)。褪黑素顯著上調乙醛酸循環(huán)中關鍵酶異檸檬酸裂解酶和蘋果酸合酶的活性,從而調控乙醛酸循環(huán)。褪黑素還能夠提高α,β-淀粉酶的活性來加速淀粉的降解。褪黑素還調控產生大量ATP的糖酵解和三羧酸循環(huán)通路。結果表明,褪黑素上調代謝通路上9個相關酶的表達來調節(jié)能量的代謝,最終為種子萌發(fā)提供能量支持。以上研究結果表明,褪黑素能夠通過促進氯化鈉脅迫下黃瓜種子中能量的合成來促進種子萌發(fā)。
[Abstract]:Seed germination is a very complex and critical biological processes in the life cycle of higher plants, it affects the completion and plant growth form. Seed germination starting on moisture absorption, terminating in the seed coat. When white radicle seeds after absorbing water, seed physiological and biochemical reaction within the corresponding break dormancy and germination. Contains a start protein synthesis during seed germination, transcription and post-translational modification, many physiological and biochemical processes of hormone synthesis and metabolism. Melatonin, the chemical name is N- acetyl -5- methoxytryptamine. Melatonin is widespread in plants, but their functions in plants research is still in the initial stage. In addition to the absorption of melatonin in plants from the outside environment can also synthesize melatonin. Exogenous melatonin treatment can improve the resistance of plants to adversity stress. This paper explores the NaCl stress. Under the influence of exogenous melatonin treatment on physiological and biochemical changes to promote germination of cucumber seeds, combined with label-free technology from the perspective of the regulation of proteomics to study the molecular mechanisms of melatonin in the regulation of seed germination, the melatonin during seed germination is more clear. The main results are as follows: (1) exogenous melatonin (1 mol/L) treatment stress could promote the germination of Cucumber Seeds under NaCl stress. Sodium chloride (150mmol/L), ROS in cucumber seeds (ROS), hydroxyl radicals and hydrogen peroxide are at a high level. Melatonin is an antioxidant, therefore, melatonin treatment can excess reactive oxygen scavenging sodium chloride stress generated by the the content of hydroxyl radicals and hydrogen peroxide in the low level, the degree of membrane lipid peroxidation decreased, thereby protecting cells from oxidative damage. At the same time as a control factor, fade Melanin by promoting seed antioxidant enzyme synthesis genes CsCu-ZnSOD, CsFe-ZnSOD, CsCAT and CsPOD to improve the expression of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity, promote the removal of excess reactive oxygen species, so as to maintain the balance of active oxygen in the body. (2) synthesis and metabolism ABA and GA are very important effects on seed germination. Exogenous melatonin can promote metabolism and GA synthesis and decomposition of sodium chloride stress on cucumber seed germination process in ABA. Under NaCl stress, on the one hand, melatonin through upregulation of ABA metabolism genes CsCYP707A1 and CsCYP707A2 accelerate the metabolism of ABA decomposition; biosynthesis of synthetic gene expression CsNECD2 at the same time, the down-regulation of ABA block ABA, ABA content decreased rapidly the seed germination process, relieve the inhibition of ABA on seed germination. On the other hand, melatonin can up regulate GA synthesis The expression of CsGA20ox and CsGA3ox, the seed of GA especially the increased synthesis of HA4, ease of NaCl stress on seed germination. (3) under NaCl stress, melatonin significantly promoted the substance in seeds (globulin) metabolism and cytoskeleton (microtubule and microfilament formation, promote cell protein) division and elongation, and promote seed germination. Melatonin also regulates many related proteins and signal transduction and stress, including 14-3-3 protein, HSP, antioxidant enzyme system, ubiquinone lysosomal protein. These results indicated that the seed germination process in the regulation of melatonin to stress signal perception of sodium chloride, remove excess reactive oxygen species. Stress tolerance and impaired protein refolding and degradation process. (4) proteomics data show that exogenous melatonin can participate in energy metabolism during seed germination of sodium chloride. Under the stress of accelerated degradation in the seed oil of melatonin treatment, the degradation products of fatty acids into the glyoxylate cycle. Melatonin significantly increased ethylene acid cycle enzymes isocitrate lyase and malate synthase activity, thereby regulating the glyoxylate cycle. Melatonin can improve the degradation of alpha, beta amylase activity to accelerate starch the regulation of melatonin. Also produced a large number of ATP of glycolysis and the tricarboxylic acid cycle three pathway. The results showed that the expression of the 9 enzymes related to the metabolism of melatonin increases metabolic pathways to regulate energy, to provide energy support for the final germination of seeds. The above results showed that melatonin could promote the synthesis of Cucumber Seeds under NaCl stress in energy to promote the seed germination.

【學位授予單位】：中國農業(yè)大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：S642.2
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本文編號：1399443