Melatonin and calcium function synergistically to promote the resilience through ROS metabolism under arsenic-induced stress
Melatonin and calcium function synergistically to promote the resilience through ROS metabolism under arsenic-induced stress
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DOI：
10.1016/j.jhazmat.2020.122882
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发表时间：
2020-11-05
影响因子：
13.6
通讯作者：
Ahmad, Parvaiz
中科院分区：
文献类型：
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作者：
Siddiqui, Manzer H.;Alamri, Saud;Ahmad, Parvaiz
褪黑激素(Mel)和钙离子(Ca~(2+))在提高对类金属毒性耐受性方面的相互作用及其潜在的生理生化机制仍不清楚。本研究表明，信号分子MEL和/或Ca~(2+)提高了蚕豆的耐性。Tara)植物对类金属砷(As)的毒性。然而，MEL和Ca~(2+)的组合比单独使用更有效。在砷胁迫下生长的植物表现出过氧化氢、超氧阴离子、电解质渗漏、脂质过氧化以及产生活性氧自由基(ROS)的酶，如NADPH氧化酶和乙醇酸氧化酶(GOx)的增加。相反，叶绿素(Chl)的生物合成和气体交换参数(净光合速率、气孔导度、胞间二氧化碳浓度)则受到抑制。在AS毒害条件下，MEL和Ca~(2+)协同抑制植物气孔保卫细胞的程序性死亡特征(核凝聚和核碎裂)、DNA损伤以及保卫细胞、叶片和根中ROS的形成。此外，在AS毒害条件下，提高了光合作用过程中的气体交换参数和参与光合作用过程的酶(碳酸氢酶和Rubisco)、Chl生物合成酶(β-氨基酚-草酸脱水酶)的活性，降低了Chl降解酶(叶绿素酶)的活性。我们的研究表明，在MEL+Ca~(2+)处理的植株中，ATP合成酶、Ca~(2+)-ATPase、Ca~(2+)-DPKase、Hsp17.6和Hsp40的表达最高，从而提高了植物对As胁迫的耐受性。此外，随着Pro合成酶(Delta(1)-吡咯啉-5-羧酸合成酶(P5CS)的增加和Pro降解酶(Pro脱氢酶)的降低，Mel+Ca~(2+)处理植株的总可溶性碳水化合物、半胱氨酸和Pro的积累增加，被认为是耐毒的。这些结果表明，MEL和钙离子联合应用通过上调质膜H+-ATPase、抗氧化系统相关酶和抗坏血酸-谷胱甘肽途径的活性来增强对AS毒性的抵抗力。
The interplay between melatonin (Mel) and calcium (Ca2+) in enhancing tolerance to metalloid toxicity and underlying physiological and biochemical mechanisms of this relationship still remains unknown. The present study reveals that the signaling molecules Mel and/or Ca2+ enhanced tolerance of Vicia faba (cv. Tara) plant to metalloid arsenic (As) toxicity. However, a combination of Mel and Ca2+ was more efficient than alone. Plants grew with As exhibited enhanced hydrogen peroxide, superoxide anion, electrolyte leakage, lipid peroxidation together with increased reactive oxygen species (ROS) producing enzymes, such as NADPH oxidase and glycolate oxidase (GOX). On the contrary, an inhibition in chlorophyll (Chl) biosynthesis and gas exchange parameters (net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration) was observed. Under As toxicity conditions, the application of Mel and Ca2+ synergistically suppressed the plants program cell death features (nucleus condensation and nucleus fragmentation) in guard cells of stomata, DNA damage, and formation of ROS in guard cells, leaves and roots. Moreover, it enhanced gas exchange parameters and activity of enzymes involved in photosynthesis process (carbonic anhydrase and RuBisco), Chl biosynthesis (delta-aminole-vulinic acid dehydratase), and decreased activity of Chl degrading enzyme (chlorophyllase) under As toxicity conditions. Our investigation evidently established that expression of ATP synthase, Ca2+-ATPase, Ca2+-DPKase, Hsp17.6 and Hsp40 was found maximum in the plants treated with Mel + Ca2+, resulting in higher tolerance of plants to As stress. Also, increased total soluble carbohydrates, cysteine, and Pro accumulation with increased Pro synthesizing enzyme (Delta(1)-pyrroline-5-carboxylate synthetase (P5CS) and decreased Pro degrading enzyme (proline dehydrogenase) in Mel + Ca2+ treated plants conferred As toxicity tolerance. The obtained results postulate strong evidence that the application of Mel along with Ca2+ enhances resilience against As toxicity by upregulating the activity of plasma membrane H+-ATPase, enzymes involved in antioxidant system, and ascorbate-glutathione pathway.