Plant Biology Department, Faculty of Science, Shahrekord University, Shahrekord, Iran.
Plant Biology Department, Faculty of Science, Shahrekord University, Shahrekord, Iran; Biotechnology Research Institute, Shahrekord University, Shahrekord, Iran.
Phytochemistry. 2020 Sep;177:112422. doi: 10.1016/j.phytochem.2020.112422. Epub 2020 Jun 25.
Melatonin (Mel) and calcium (Ca) have a regulatory role in the induction of specialized metabolites production and defensive responses against stresses. Therefore, in this study, the effects of Mel and Ca and the possible relationship between them in the increase of the production of phenolic compounds in Dracocephalum kotschyi Boiss. under both control and salinity stress conditions were investigated. The results showed that 75 mM NaCl reduced shoot dry biomass but elevated HO content, electrolyte leakage (EL) level, total phenolic and flavonoid contents (TPC and TFC), and DPPH scavenging capacity. Salinity stress also upregulated gene expression of phenylalanine ammonia-lyase (PAL) and rosmarinic acid synthase (RAS), as well as the activities of PAL and tyrosine ammonia-lyase (TAL) enzymes. Pre-treatment of the plants with CaCl and Mel affected these attributes in a dose-dependent manner. Application of 5 mM Ca and 100 μM Mel improved shoot dry biomass and reduced the level of EL and HO content but enhanced TPC and TFC, DPPH scavenging capacity, PAL and TAL activities, PAL and RAS transcripts, and content of rosmarinic acid (RA), luteolin flavone (LF) and apigenin flavone (AF) under salinity stress. Pre-treatment of D. kotschyi with lanthanum chloride (LaCl) as a plasma membrane channel blocker, ethylene glycol tetra-acetic acid (EGTA) as a Ca chelator and trifluoperazine (TFP) as a calmodulin (CaM) antagonist, impaired Mel effects on the above attributes under salinity stress. In contrast, pre-treatment with p-chlorophenylalanine (p-CPA), as an inhibitor of Mel biosynthesis, did not impair the impacts of Ca on the production of phenolic compounds in salt-exposed plants. These results suggested that the effect of Mel on the induction of phenolic compounds production requires the influx of extracellular Ca into the cells and is dependent on Ca/CaM signaling.
褪黑素 (Mel) 和钙 (Ca) 在诱导特殊代谢产物的产生和对胁迫的防御反应中具有调节作用。因此，在这项研究中，研究了 Mel 和 Ca 的作用及其在控制和盐胁迫条件下增加Dracocephalum kotschyi Boiss.酚类化合物产量方面的可能关系。结果表明，75 mM NaCl 降低了地上部干生物量，但提高了 HO 含量、电解质渗透率 (EL) 水平、总酚和类黄酮含量 (TPC 和 TFC) 以及 DPPH 清除能力。盐胁迫还上调了苯丙氨酸解氨酶 (PAL) 和迷迭香酸合酶 (RAS) 的基因表达，以及 PAL 和酪氨酸解氨酶 (TAL) 酶的活性。植物用 CaCl 和 Mel 预处理以剂量依赖的方式影响这些特性。应用 5 mM Ca 和 100 μM Mel 提高了地上部干生物量，降低了 EL 水平和 HO 含量，但增强了 TPC 和 TFC、DPPH 清除能力、PAL 和 TAL 活性、PAL 和 RAS 转录物以及迷迭香酸 (RA)、木犀草素黄酮 (LF) 和芹菜素黄酮 (AF) 的含量在盐胁迫下。作为质膜通道阻断剂的氯化镧 (LaCl)、作为 Ca 螯合剂的乙二醇四乙酸 (EGTA) 和作为钙调蛋白 (CaM) 拮抗剂的三氟拉嗪 (TFP) 预处理，破坏了 Mel 对盐胁迫下上述特性的影响。相比之下，用对氯苯丙氨酸 (p-CPA)预处理，作为 Mel 生物合成的抑制剂，并没有损害 Ca 对盐暴露植物中酚类化合物产生的影响。这些结果表明，Mel 对诱导酚类化合物产生的影响需要细胞外 Ca 流入细胞，并依赖于 Ca/CaM 信号。
