Melatonin alleviates iron stress by improving iron homeostasis, antioxidant defense and secondary metabolism in cucumber
Melatonin alleviates iron stress by improving iron homeostasis, antioxidant defense and secondary metabolism in cucumber
复制标题
褪黑激素通过改善黄瓜中的铁稳态、抗氧化防御和次级代谢来缓解铁应激
DOI：
10.1016/j.scienta.2020.109205
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发表时间：
2020-04-30
影响因子：
4.3
通讯作者：
Chen, Shuangchen
中科院分区：
文献类型：
--
作者：
Ahammed, Golam Jalal;Wu, Meijuan;Chen, Shuangchen
铁是植物和动物的必需元素;然而，铁的缺乏或过量都会导致植物受到胁迫。本研究以黄瓜为材料，探讨了褪黑激素（N-acetyl-5-methoxytryptamine，N-acetyl-5-methoxytryptamine）诱导黄瓜地上部耐铁毒的机制。在水培条件下，低铁和高铁供应均降低了黄瓜的生长和生物量积累，导致黄瓜叶片失绿和氧化胁迫，降低了叶绿素含量、光合速率和蒸腾速率。值得注意的是，低铁处理的负面影响比高铁处理更深刻。而外源褪黑激素的应用则通过提高抗氧化酶和次级代谢相关酶的活性和转录水平，提高内源褪黑激素含量，减少电解质渗漏、活性氧积累和脂质过氧化，从而缓解了对生长、生化和生理参数的抑制，以及褪黑激素处理后低铁和高铁条件下酚类和类黄酮的浓度。对叶片和根中铁含量的分析表明，褪黑激素显著增加了低铁条件下的铁含量，但在高铁条件下，它降低了相同的。此外，褪黑激素在低铁条件下增加FRO 2和IRT 1的转录水平，但在高铁条件下降低这些转录水平，表明褪黑激素在低铁和高铁条件下的铁吸收中起双重作用。这项研究扩展了褪黑激素在植物中的胁迫改善作用，并可能对低铁和高铁土壤中作物的农艺管理产生潜在的影响。
Iron is an essential element for plants and animals; however, deficit or excess iron can result in stress on plants. In this study, we unveiled the mechanisms of shoot-based tolerance to iron toxicity by melatonin (N-acetyl-5-methoxytryptamine) in cucumber plants. Both low and high iron (Fe) supply in hydroponics decreased growth and biomass accumulation, induced chlorosis and oxidative stress, and reduced chlorophyll content, photosynthesis rate and transpiration rate in cucumber leaves. Notably, the negative effect of low-Fe was more profound than that of high-Fe treatment. However, exogenous melatonin application alleviated those inhibitions in growth, biochemical and physiological parameters, which entailed an elevation of endogenous melatonin content and a reduction of electrolyte leakage, reactive oxygen species accumulation and lipid peroxidation by improving the activity and transcripts of antioxidant enzymes and secondary metabolism-related enzymes, and concentrations of phenols and flavonoids under low and high iron conditions after melatonin treatment. Analysis of iron content in leaves and roots revealed that melatonin significantly increased the iron content under low-Fe conditions, but it decreased the same under high-Fe conditions. Moreover, melatonin increased the transcript levels of FRO2 and IRT1 under low-Fe, but it decreased those transcripts under high-Fe, suggesting that melatonin plays a dual role in iron uptake under low and high iron conditions. This study expands the stress ameliorative role of melatonin in plants and may have potential implications in agronomic management of crops in low and high iron prone soils.