Melatonin enhances astaxanthin accumulation in the green microalga Haematococcus pluvialis by mechanisms possibly related to abiotic stress tolerance
Melatonin enhances astaxanthin accumulation in the green microalga Haematococcus pluvialis by mechanisms possibly related to abiotic stress tolerance
复制标题
褪黑激素通过可能与非生物胁迫耐受性相关的机制增强绿色微藻雨生红球藻中虾青素的积累
DOI：
10.1016/j.algal.2018.05.021
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发表时间：
2018-07-01
影响因子：
5.1
通讯作者：
Yu, Xuya
中科院分区：
文献类型：
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作者：
Ding, Wei;Zhao, Peng;Yu, Xuya
褪黑激素（N-乙酰基-5-甲氧基色胺）被广泛认为是高等植物和哺乳动物抵抗各种生物和非生物胁迫的重要信使。然而，褪黑激素在微藻中的作用却很少被研究。本研究首次利用褪黑激素在有限氮和强光条件下促进虾青素的生物合成。研究了应激反应过程中褪黑素与第二信使一氧化氮（NO）和水杨酸（SA）的相互作用。此外，还对脂肪酸的生物合成进行了探索。最后，通过实时荧光定量PCR同时监测添加褪黑激素的雨生红球藻LUGU中虾青素生物合成基因的表达水平。用10 μ M褪黑激素处理后，微藻的虾青素含量增加了2.36倍。最大虾青素含量为31.32 mg g（-1）。褪黑激素引起的NO和SA产生的增加与虾青素合成基因表达的上调和虾青素生物合成的增强平行发生。雨生花脂肪酸组成的分析表明，褪黑激素刺激C16：0（棕榈酸）的生产，因此，虾青素酯的百分比高于对照藻类中观察到的。此外，抑制剂，即羧基PTIO，多效唑，N-乙酰-L-半胱氨酸，显着抑制二级信使的水平。同时，褪黑激素介导的作用，在虾青素含量的上升被阻止时，SA和NO依赖的途径被抑制。这些结果表明，褪黑激素在H.雨生植物
Melatonin (N-acetyl-5-methoxytryptamine) is widely regarded as an important messenger in higher plants and mammals in their resistance to various biotic and abiotic stresses. However, the role of melatonin in microalgae has been rarely investigated. In this study, melatonin was first used to promote astaxanthin biosynthesis under limited nitrogen and high light conditions. The interactions between melatonin and the secondary messengers, namely, nitric oxide (NO) and salicylic acid (SA), during the stress response were also investigated. Moreover, fatty acid biosynthesis was explored. Finally, the expression levels of astaxanthin biosynthesis genes in Haematococcus pluvialis LUGU supplemented with melatonin were simultaneously monitored through quantitative real-time PCR. The astaxanthin content of the microalgae increased 2.36-fold after treatment with 10 mu M of melatonin. The maximal astaxanthin content achieved was 31.32 mg g(-1). The increased NO and SA production caused by melatonin occurred in parallel with the up-regulation of the expression of astaxanthin biosynthesis genes and the enhancement in astaxanthin biosynthesis in H. pluvialis LUGU. The analysis of fatty acid composition showed that melatonin stimulated the production of C16:0 (palmitic acid); thus, the percentage of astaxanthin esters was higher than that observed in the control algae. Furthermore, the inhibitors, namely, carboxy-PTIO, paclobutrazol, and N-acetyl-L-cysteine, significantly suppressed the levels of secondary messengers. Meanwhile, the role of melatonin in mediating the rise in astaxanthin content was prevented when the SA- and NO-dependent pathways were inhibited. These findings indicate that melatonin plays a physiological role in direct and indirect responses to abiotic stresses in H. pluvialis.