Peptide AEDL and Glutathione Stimulates Root Development Nicotiana tabacum

Abstract

Reactive oxygen species (ROS) are essential molecules involved in intercellular communication, signal transduction, and metabolic processes. Abiotic stresses cause the accumulation of excess ROS in plant cells. The issue of regulating the antioxidant protection of plants using natural and synthetic compounds with antioxidant activity still remains one of the most important and relevant areas of fundamental and applied research. Glutathione (GSH) plays an important role in the stress resistance and redox homeostasis of plant cells and effectively protects the cell from the stress-induced generation of ROS. An increase in the GSH content in plant cells can contribute to an increase in plant resistance to various types of stressors. We have shown that growing Nicotiana tabacum in the presence of tetrapeptide AEDL (AlaGluAspLeu) contributes to an increase in the GSH content by 3.24 times. At the same time, the tobacco plant was more developed, especially its root system. A scheme of the mechanism behind the regulation of the redox balance in the stem cell niche and the participation of the AEDL and GSH peptides in the regulation of the fate of stem cells was proposed.

Keywords: GSH; ROS; peptide AEDL; stem cells.

Figure 1

Nicotiana tabacum, grown in different conditions. Data were expressed as mean ± standard deviation (SD; n = 30).

Figure 2

Expression RGF1 gene in root Nicotiana tabacum. Data are expressed as mean ± standard deviation (n = 3); a–d—indicate significant difference using Student’s t-test (p < 0.05).

Figure 3

(A) Distribution of ROS+ and ROS− cells in the root zones N. tabacum. Control—(a,a’); 150 mM NaCl—(b,b’); AEDL—(c,c’); AEDF + 150 mM NaCl—(d,d’). DZ—differentiation zone; EZ—elongation zone; MZ—meristem zone; QC—quiescent center. Bar 400 µm. (B) The intensity of ROS fluorescence in N. tabacum, grown in different conditions. (C) Distribution of fluorescence intensity in the root zones. (D) Distribution of fluorescence intensity in the root tissues. Data are expressed as mean ± standard deviation (n = 3); a–c—indicate significant difference using Student’s t-test (p < 0.05).

Figure 3

(A) Distribution of ROS+ and ROS− cells in the root zones N. tabacum. Control—(a,a’); 150 mM NaCl—(b,b’); AEDL—(c,c’); AEDF + 150 mM NaCl—(d,d’). DZ—differentiation zone; EZ—elongation zone; MZ—meristem zone; QC—quiescent center. Bar 400 µm. (B) The intensity of ROS fluorescence in N. tabacum, grown in different conditions. (C) Distribution of fluorescence intensity in the root zones. (D) Distribution of fluorescence intensity in the root tissues. Data are expressed as mean ± standard deviation (n = 3); a–c—indicate significant difference using Student’s t-test (p < 0.05).

Figure 4

Expression of MnSOD and Cu/ZnSOD genes in N. tabacum in roots (1) and leaves (2), grown in different conditions: (A,C) control; (B,D) 150 mM NaCl. Data are expressed as mean ± standard deviation (n = 3); a,b—indicate significant difference using Student’s t-test (p < 0.05).

Figure 5

Distribution of SOD activity (nM/mg protein/min) in root zones of Nicotiana tabacum. MZ—meristem zone; EZ—elongation zone; DZ—differentiation zone. Data are expressed as mean ± standard deviation (n = 3); a–o—indicate a significant difference using Student’s t-test (p < 0.05).

Figure 6

Expression of the GSH1 and GSH2 genes in N. tabacum in roots (1) and leaves (2), grown in different conditions: (A,C) control; (B,D) 150 mM NaCl. Data are expressed as mean ± standard deviation (n = 3); a,b—indicate significant difference using Student’s t-test (p < 0.05).

Figure 7

Expression of the GR and GST genes in N. tabacum in roots (1) and leaves (2), grown in different conditions: (A,C) control; (B,D) 150 mM NaCl. Data are expressed as mean ± standard deviation (n = 3); a,b—indicate significant difference using Student’s t-test (p < 0.05).

Figure 8

RGF1 peptide and GSH form a positive feedback loop that activates stem cell proliferation. AEDL peptide and WUS form a negative feedback loop that activates stem cell differentiation.