Improvement of cold stress resistance via free radical scavenging ability and promoted water status and photosynthetic capacity of gallic acid in soybean leaves

Abstract

Plant polyphenols exhibit a wide variety of biological activities such as antimutagenicity, anticarcinogenicity and antioxidative activity. There is no report whether gallic acid (GLA), a naturally occurring plant phenol, is able to activate the plant defense system under cold stress. For this purpose, after soybean (Glycine max) was hydroponically grown for 3 weeks, seedlings were treated with gallic acid (GLA; 1 and 2 mM) and cold stress (5 o C and 10 o C) and GLA and stress combination for 72 h. The inhibition in growth, water content (RWC), osmotic potential (Ψп) and photosynthetic activity observed under stress and was more at the lowest temperature. Stress also elicited the accumulation of proline (Pro) only at 5 o C. While the capacity to maintain high growth, RWC, Ψп and photosynthetic efficiency was observed in GLA-treated plants under stress, Pro accumulation could not achieve with GLA plus stress. Any increase in total activities of superoxide dismutase (SOD) and catalase (CAT) induced by stress treatments determined. The lower cold stress caused an increase in the activities of ascorbate peroxidase (APX), glutathione reductase (GR) and NADPH oxidase (NOX). GLA treatment under stress (especially at 5 o C) could supply the increased activities of SOD, CAT, APX and GR. Also, exogenous GLA application to stress-treated plants increased the enzyme activities in ascorbate-glutathione cycle such as monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) and, contents of ascorbate (AsA) and glutathione. After GLA application under stress, it is observed reduction in hydrogen peroxide (H 2 O 2 ) and the levels of lipid peroxidation (TBARS), and induction of hydroxyl radical (OH • ) scavenging. Our results suggest that GLA is a potent inducer for induction of the scavenging activity of radicals as well as effectively usage of water status and photosynthetic capacity.

Cold stress in soybean (Glycine max L.) roots: Exogenous gallic acid promotes water status and increases antioxidant activities

“…Interestingly, in a study on soybean leaves (Yildiztugay et al 2017) , the same result was observed, namely that there was no increase of SOD activity in stress-treated soybean leaves, although an increase of H 2 O 2 content was induced. As detected by Yildiztugay et al (2017), enhancement of H 2 O 2 content in stress-treated roots of soybean plants was related to increased NOX activity in their leaves. On the other hand, GLA application prevented the decline of SOD activity induced by stress.…”

“…However, in the present study, GLA did not contribute to elimination of the damage caused by cold stress through alteration of the reduced/oxidised GSH ratio under stress conditions. On the other hand, GLA application in soybean leaves treated with stress (5°C) activated the ascorbate-glutathione cycle (Yildiztugay et al 2017). These results suggest no apparent role for the ascorbate-glutathione cycle in damage alleviation by GLA in soybean roots under cold stress.…”

“…This result could be linked with a repressed capacity of scavenging systems for H 2 O 2 under stress or another source of H 2 O 2 such as glycolate oxidases, glucose oxidases, sulphite oxidases and plasma membrane NADPH oxidases (NOX) (Slesak et al 2007;Keunen et al 2013). Interestingly, in a study on soybean leaves (Yildiztugay et al 2017) , the same result was observed, namely that there was no increase of SOD activity in stress-treated soybean leaves, although an increase of H 2 O 2 content was induced. As detected by Yildiztugay et al (2017), enhancement of H 2 O 2 content in stress-treated roots of soybean plants was related to increased NOX activity in their leaves.…”

Does Exogenously Applied Gallic Acid Regulate the Enzymatic and Non-Enzymatic Antioxidants in Wheat Roots Exposed to Cadmium Stress?

“…The level of lipid peroxidation called as thiobarbituric acid reactive substances (TBARS) was detected according to Yildiztugay et al [9].…”

“…For determination of SOD isoforms and total SOD activity, the procedure was completed [8]. Analysis of CAT isozymes/activities was performed the procedure given by Yildiztugay et al [9]. POX isozymes, total POX activity, NOX isozyme and its activity were done [8,9].…”