Effects of Selenium on Serotonin Synthesis and the Glutathione Redox Cycle in Plum Leaves

Abstract

Selenium (Se), an essential micronutrient for humans, is also a beneficial nutrient for growth and development of many plants. The aim of the present study was to determine whether low-dose Se application could increase plum growth and serotonin synthesis, as well as upregulate the glutathione redox cycle. Two-year-old plum trees were treated with Se 6+ (Na 2 SeO 4) and Se 2− (SeMet). Growth parameters, levels of serotonin synthesis precursors, compounds and enzymes of the glutathione (GSH) redox cycle, and the antioxidant capacity were analyzed. Results showed that plant height and stem diameter were increased by Se treatment. The leaf Se content was significantly increased; tryptophan was not affected by Se treatment, while the 5hydroxytryptophan content was significantly higher than control. Although serotonin levels were also increased, the effect was not significant, and no tryptamine was detected in our study. On the 30th day, the MDA content in Se 2− was highest followed by the control and Se 6+ treatment, and the activities of T-AOT and CAT were increased, while GST was reduced by Se treatment. The two forms of Se treatments increased the activity of GPX and GR, and the total content of GSH + glutathione disulfide (GSSG) at the end of treatment. Furthermore, the level of GSH and GSH/GSSG was instable changed. GSSG content was similar during the treatment time except on the 20 days. Conclusively, the pathway of plum serotonin was clear, both Se 6+ and Se 2− could influence the serotonin synthesis. Additionally, the GSH redox cycle was sensitive to the Se application. Moreover, Se 6+ performed better than Se 2− on leaf Se content, plant growth parameters, and antioxidant capacity.

Seed Priming with the Selenium Nanoparticles Maintains the Redox Status in the Water Stressed Tomato Plants by Modulating the Antioxidant Defense Enzymes

“…As a result, the increase in tocopherols observed in our study could be attributed to increased DHAR activity [ 57 ]. Sun et al [ 58 ] previously demonstrated that Se increases the activities of ascorbate-glutathione cycle enzymes. The nanoparticles-mediated increased activities of these enzymes have been documented by the previous researchers [ 59 , 60 ].…”

Effects of heat shock on energy metabolism and antioxidant defence in a tropical fish speciesPsalidodon bifasciatus

“…Enzymes: GP, glycogen phosphorylase; G6Pase, glucose-6-phosphatase; HK, hexokinase; PFK, phosphofructokinase; PK, pyruvate kinase; G6PDH, glugose-6-phosphate dehydrogenase; LDH, lactate dehydrogenase; CS, citrate synthase; MDH, malate dehydrogenase regeneration of GSH from GSSG using NADPH (nicotinamide adenine dinucleotide phosphate) as an electron donor (Lushchak & Bagnyukova, 2006a;McCarthy, 2014). This de novo synthesis was likely activated by the increase in GST at the same exposure time in P. bifasciatus (Sun et al, 2020). Nonetheless, there was a reduction in GSH after 24 h of exposure, which could be explained by the liver being the main source of glutathione in vertebrates (Hermes-Lima, 2004;Nakano et al, 2014) that could have acted as a source of GSH to other organs.…”

Reactive Oxygen, Nitrogen, and Sulfur Species (RONSS) as a Metabolic Cluster for Signaling and Biostimulation of Plants: An Overview

“…Se has also been related to the increase in the activity of other non-catalytic proteins, such as thioredoxin (TrxR) and protein P [ 114 ]. The impact of Se on antioxidant metabolites is associated with sulfur metabolism since both elements share uptake and assimilation pathways; the effects on the concentration of GSH and GSSH have been described in Allium [ 115 ] and Prunus domestica [ 116 ]. In species that can reach high concentrations of S, such as broccoli, the accumulation of glucosinolates is increased [ 117 ].…”