Salt Stress Affects the Redox Status of Arabidopsis Root Meristems

Abstract In the last decade contradictory results have been published as to whether exogenous salicylic acid (SA) can increase salt stress tolerance in cultivated plants by inducing an antioxidant response. Salt stress injury in tomato was mitigated only in cases when the plant was hardened with a high concentration of SA (~10−4 M), low concentrations were ineffective. An efficient accumulation of Na+ in older leaves is a well-known response to salt stress in tomato plants (Solanum lycopersicum cv. Rio fuego) but it remains largely unexplored whether young and old leaves or root tissues have a distinct antioxidant status during salt stress after hardening with 10−7 M or 10−4 M SA. The determination of superoxide dismutase (SOD) and catalase (CAT) activity revealed that the SA-induced transient increases in these enzyme activities in young leaf and/or root tissues did not correlate with the salt tolerance of plants. Salt stress resulted in a tenfold increase in ascorbate peroxidase (APX) activities of young leaves and significant increases in APX and glutathione reductase (GR) activities of the roots hardened with 10−4 M SA. Both total ascorbate (AsA) and glutathione pools reached their highest levels in leaves after 10−7 M SA pre-treatment. However, in contrast to the leaves, the total pool of AsA decreased in the roots under salt stress and thus, due to low APX activity, active oxygen species were scavenged by ascorbate non-enzymatically in these tissues. The increased GR activities in the roots after treatment with 10−4 M SA enabled plants to enhance the reduced glutathione (GSH) pool and maintain the redox status of AsA under high salinity, which led to increased salt tolerance.

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Plastid-Localized Glutathione Reductase2-Regulated Glutathione Redox Status Is Essential for Arabidopsis Root Apical Meristem Maintenance

The Plant Cell ◽

10.1105/tpc.113.117028 ◽

2013 ◽

Vol 25 (11) ◽

pp. 4451-4468 ◽

Cited By ~ 60

Author(s):

X. Yu ◽

T. Pasternak ◽

M. Eiblmeier ◽

F. Ditengou ◽

P. Kochersperger ◽

...

Keyword(s):

Apical Meristem ◽

Redox Status ◽

Root Apical Meristem ◽

Arabidopsis Root ◽

Meristem Maintenance ◽

Glutathione Redox

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A Signaling Module Controlling the Stem Cell Niche in Arabidopsis Root Meristems

Current Biology ◽

10.1016/j.cub.2009.03.060 ◽

2009 ◽

Vol 19 (11) ◽

pp. 909-914 ◽

Cited By ~ 283

Author(s):

Yvonne Stahl ◽

René H. Wink ◽

Gwyneth C. Ingram ◽

Rüdiger Simon

Keyword(s):

Stem Cell ◽

Stem Cell Niche ◽

Arabidopsis Root ◽

Root Meristems ◽

Cell Niche

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Metabolic Adjustment of Arabidopsis Root Suspension Cells During Adaptation to Salt Stress and Mitotic Stress Memory

Plant and Cell Physiology ◽

10.1093/pcp/pcy231 ◽

2018 ◽

Vol 60 (3) ◽

pp. 612-625 ◽

Cited By ~ 4

Author(s):

Hyun Jin Chun ◽

Dongwon Baek ◽

Hyun Min Cho ◽

Hyun Suk Jung ◽

Myeong Seon Jeong ◽

...

Keyword(s):

Salt Stress ◽

Suspension Cells ◽

Arabidopsis Root ◽

Stress Memory ◽

Mitotic Stress ◽

Metabolic Adjustment

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Compensation of Mutation in Arabidopsis glutathione transferase (AtGSTU) Genes under Control or Salt Stress Conditions

International Journal of Molecular Sciences ◽

10.3390/ijms21072349 ◽

2020 ◽

Vol 21 (7) ◽

pp. 2349 ◽

Cited By ~ 1

Author(s):

Edit Horváth ◽

Krisztina Bela ◽

Ágnes Gallé ◽

Riyazuddin Riyazuddin ◽

Gábor Csomor ◽

...

Keyword(s):

Salt Stress ◽

Glutathione Transferase ◽

Redox Homeostasis ◽

Redox Status ◽

Glutathione Transferases ◽

Wild Type ◽

General Role ◽

First Time ◽

Gst Activity

Glutathione transferases (GSTs) play a crucial role in detoxification processes due to the fact of their glutathione (GSH) conjugating activity, and through glutathione peroxidase or dehydroascorbate reductase (DHAR) activities, they influence the redox state of GSH and ascorbate (AsA). The plant-specific tau (GSTU) group is the largest class of Arabidopsis GSTs, and their members are involved in responses to different abiotic stresses. We investigated the effect of salt stress on two-week-old Arabidopsis thaliana wild-type (Col-0), Atgstu19 and Atgstu24 mutant plants after applying 150 mM NaCl for two days. The Atgstu19 seedlings had lower GST activity and vitality both under control conditions and after salt stress than the wild-type, but the level of total ROS was similar to the Col-0 plants. The GST activity of the knockout Atgstu24 mutant was even higher under control conditions compared to the Col-0 plants, while the ROS level and its vitality did not differ significantly from the wild-type. Analysis of the AtGSTU expression pattern revealed that the mutation in a single AtGSTU gene was accompanied by the up- and downregulation of several other AtGSTUs. Moreover, elevated AsA and GSH levels, an altered GSH redox potential and increased DHAR and glutathione reductase activities could help to compensate for the mutation of AtGSTU genes. The observed changes in the mutants suggest that the investigated isoenzymes influence the redox homeostasis under control conditions and after NaCl treatment in Arabidopsis seedlings. These data indicate for the first time the more general role of a temporary shift of redox status as part of GST mechanisms and regulation.

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