Salt stress in Arabidopsis thaliana seedlings: Role of indoleamines in stress alleviation

Salinity is a major environmental stress in agriculture with significantly detrimental effects on crop productivity. The development of strategies to enhance salinity stress tolerance in plants is essential to ensure crop production in saline environments. Melatonin (Mel) and serotonin (Ser) accumulate in response to environmental stresses and are presumed to play protective roles and improve growth of tissues during recovery. In this study, the effects of Mel and Ser were investigated in Arabidopsis under NaCl stress. Exogenous Mel (10 µM) and Ser (10 µM) treatment significantly increased fresh weight, lateral root number, and shoot height in A. thaliana seedlings exposed to NaCl stress (25 mM and 50 mM) compared to the non-treated control seedlings. In order to understand the role of these indoleamines in alleviating salt stress, we investigated the effects of Mel and Ser treatments on the expression of salt stress responsive genes including, transcription factors involved in abscisic acid (ABA) signaling pathway, ABA-INSENSITIVE 3 (ABI3)and ABA-INSENSITIVE 5 (ABI5); ABA responsive gene, RESPONSIVE TO DESSICATION 29B (RD29B), ABA-independent gene, RESPONSIVE TO DESSICATION 29A (RD29A) and Arabidopsis trithorax-like gene (ATX1) which function in stress responses via ABA-dependent and ABA-independent manner. Other genes included, ROS-signaling transcription factor ZAT10 and ZAT12, and the genes encoding ion transporters crucial for maintaining ion homeostasis, HIGH AFFINITY K+ TRANSPORTER 5 (HAK5) and SALT OVERLY SENSITIVE 1 (SOS1). Mel (10 µM) pre-treatment for 24 hrs followed by 50 mM salt treatment up-regulated ABI3, RD29B, ZAT12 and HAK5. The Ser (10 µM) pre-treatment significantly up-regulated ZAT12.These results indicate that indoleamine pre-treatment improved plant growth under salt stress with Mel facilitating salt tolerance via upregulation of ABA responsive genes, mediation of antioxidant defense systems to counteract the salt-induced ROS overproduction as well as controlling ion homeostasis. Although Ser displayed no significant effects on ABA signaling, it was found to increase the expression of antioxidant defense gene, ZAT12. This study demonstrates the importance of indoleamine pathway in mediation of salt stress response and provides the first indication of the involvement of Ser in salt stress tolerance.

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Exogenous Tebuconazole and Trifloxystrobin Regulates Reactive Oxygen Species Metabolism Toward Mitigating Salt-Induced Damages in Cucumber Seedling

Plants ◽

10.3390/plants8100428 ◽

2019 ◽

Vol 8 (10) ◽

pp. 428 ◽

Cited By ~ 5

Author(s):

Sayed Mohsin ◽

Mirza Hasanuzzaman ◽

M. Bhuyan ◽

Khursheda Parvin ◽

Masayuki Fujita

Keyword(s):

Reactive Oxygen Species ◽

Salt Stress ◽

Antioxidant Defense ◽

Ion Homeostasis ◽

Reactive Oxygen ◽

Cucumber Plant ◽

Enzymatic Antioxidants ◽

Oxygen Species ◽

Exogenous Application ◽

Antioxidant Defense Systems

The present study investigated the role of tebuconazole (TEB) and trifloxystrobin (TRI) on cucumber plants (Cucumis sativus L. cv. Tokiwa) under salt stress (60 mM NaCl). The cucumber plants were grown semi-hydroponically in a glasshouse. Plants were exposed to two different doses of fungicides (1.375 µM TEB + 0.5 µM TRI and 2.75 µM TEB + 1.0 µM TRI) solely and in combination with NaCl (60 mM) for six days. The application of salt phenotypically deteriorated the cucumber plant growth that caused yellowing of the whole plant and significantly destructed the contents of chlorophyll and carotenoids. The oxidative damage was created under salinity by increasing the contents of malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolytic leakage (EL) resulting in the disruption of the antioxidant defense system. Furthermore, in the leaves, stems, and roots of cucumber plants increased Na+ content was observed under salt stress, whereas the K+/Na+ ratio and contents of K+, Ca2+, and Mg2+ decreased. In contrast, the exogenous application of TEB and TRI reduced the contents of MDA, H2O2, and EL by improving the activities of enzymatic and non-enzymatic antioxidants. In addition, ion homeostasis was regulated by reducing Na+ uptake and enhanced K+ accumulation and the K+/Na+ ratio after application of TEB and TRI. Therefore, this study indicates that the exogenous application of TEB and TRI enhanced salt tolerance in cucumber plants by regulating reactive oxygen species production and antioxidant defense systems.

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Seed Treatment with Trichoderma longibrachiatum T6 Promotes Wheat Seedling Growth under NaCl Stress Through Activating the Enzymatic and Nonenzymatic Antioxidant Defense Systems

International Journal of Molecular Sciences ◽

10.3390/ijms20153729 ◽

2019 ◽

Vol 20 (15) ◽

pp. 3729 ◽

Cited By ~ 1

Author(s):

Shuwu Zhang ◽

Bingliang Xu ◽

Yantai Gan

Keyword(s):

Salt Stress ◽

Antioxidant Defense ◽

Wheat Seedling ◽

Nacl Stress ◽

Ros Scavenging ◽

Wheat Seedlings ◽

Defense Systems ◽

Antioxidant Defense Systems ◽

Scavenging Enzymes ◽

Different Levels

Salt stress is one of the major abiotic stresses limiting crop growth and productivity worldwide. Species of Trichoderma are widely recognized for their bio-control abilities, but little information is regarding to the ability and mechanisms of their promoting plant growth and enhancing plant tolerance to different levels of salt stress. Hence, we determined (i) the role of Trichoderma longibrachiatum T6 (TL-6) in promoting wheat (Triticum aestivum L.) seed germination and seedling growth under different levels of salt stress, and (ii) the mechanisms responsible for the enhanced tolerance of wheat to salt stress by TL-6. Wheat seeds treated with or without TL-6 were grown under different levels of salt stress in controlled environmental conditions. As such, the TL-6 treatments promoted seed germination and increased the shoot and root weights of wheat seedlings under both non-stress and salt-stress conditions. Wheat seedlings with TL-6 treatments under different levels of NaCl stress increased proline content by an average of 11%, ascorbate 15%, and glutathione 28%; and decreased the contents of malondialdehyde (MDA) by an average of 19% and hydrogen peroxide (H2O2) 13%. The TL-6 treatments induced the transcriptional level of reactive oxygen species (ROS) scavenging enzymes, leading to the increases of glutathione s-transferase (GST) by an average of 17%, glutathione peroxidase (GPX) 16%, ascorbate peroxidase (APX) 17%, glutathione reductase (GR) 18%, dehydroascorbate reductase (DHAR) 5%. Our results indicate that the beneficial strain of TL-6 effectively scavenged ROS under NaCl stress through modulating the activity of ROS scavenging enzymes, regulating the transcriptional levels of ROS scavenging enzyme gene expression, and enhancing the nonenzymatic antioxidants in wheat seedling in response to salt stress. Our present study provides a new insight into the mechanisms of TL-6 can activate the enzymatic and nonenzymatic antioxidant defense systems and enhance wheat seedling tolerance to different levels of salt stress at physiological, biochemical and molecular levels.

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Manganese-induced salt stress tolerance in rice seedlings: regulation of ion homeostasis, antioxidant defense and glyoxalase systems

Physiology and Molecular Biology of Plants ◽

10.1007/s12298-016-0371-1 ◽

2016 ◽

Vol 22 (3) ◽

pp. 291-306 ◽

Cited By ~ 47

Author(s):

Anisur Rahman ◽

Md. Shahadat Hossain ◽

Jubayer-Al Mahmud ◽

Kamrun Nahar ◽

Mirza Hasanuzzaman ◽

...

Keyword(s):

Salt Stress ◽

Stress Tolerance ◽

Antioxidant Defense ◽

Ion Homeostasis ◽

Rice Seedlings ◽

Salt Stress Tolerance

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Role of Grafting in Tolerance to Salt Stress in Melon (Cucumis melo L.) Plants: Ion regulation and antioxidant defense systems

Tarla Bitkileri Merkez Arastirma Enstitusu ◽

10.38042/biotechstudies.932376 ◽

2021 ◽

Vol 30 (1) ◽

pp. 22-32

Author(s):

Şebnem KUŞVURAN ◽

Elif KAYA ◽

Ş. Şebnem ELLİALTIOĞLU

Keyword(s):

Salt Stress ◽

Cucumis Melo ◽

Antioxidant Defense ◽

Ion Regulation ◽

Defense Systems ◽

Antioxidant Defense Systems ◽

Cucumis Melo L

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Nitric Oxide Regulates Plant Growth, Physiology, Antioxidant Defense, and Ion Homeostasis to Confer Salt Tolerance in the Mangrove Species, Kandelia obovata

Antioxidants ◽

10.3390/antiox10040611 ◽

2021 ◽

Vol 10 (4) ◽

pp. 611

Author(s):

Mirza Hasanuzzaman ◽

Masashi Inafuku ◽

Kamrun Nahar ◽

Masayuki Fujita ◽

Hirosuke Oku

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Antioxidant Defense ◽

Intercellular Co2 Concentration ◽

Ion Homeostasis ◽

Monodehydroascorbate Reductase ◽

Kandelia Obovata ◽

Ion Toxicity ◽

Antioxidant Defense Systems ◽

Nutrient Homeostasis

Facultative halophyte Kandelia obovata plants were exposed to mild (1.5% NaCl) and severe (3% NaCl) salt stress with or without sodium nitroprusside (SNP; 100 µM; a NO donor), hemoglobin (Hb, 100 µM; a NO scavenger), or Nω-nitro-L-arginine methyl ester (L-NAME, 100 µM; a NO synthase inhibitor). The plants were significantly affected by severe salt stress. They showed decreases in seedling growth, stomatal conductance, intercellular CO2 concentration, SPAD value, photosynthetic rate, transpiration rate, water use efficiency, and disrupted antioxidant defense systems, overproduction of reactive oxygen species, and visible oxidative damage. Salt stress also induced ion toxicity and disrupted nutrient homeostasis, as indicated by elevated leaf and root Na+ contents, decreased K+ contents, lower K+/Na+ ratios, and decreased Ca contents while increasing osmolyte (proline) levels. Treatment of salt-stressed plants with SNP increased endogenous NO levels, reduced ion toxicity, and improved nutrient homeostasis while further increasing Pro levels to maintain osmotic balance. SNP treatment also improved gas exchange parameters and enhanced antioxidant enzymes’ activities (catalase, ascorbate peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase). Treatment with Hb and l-NAME reversed these beneficial SNP effects and exacerbated salt damage, confirming that SNP promoted stress recovery and improved plant growth under salt stress.

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Ion Homeostasis and Metabolome Analysis of Arabidopsis 14-3-3 Quadruple Mutants to Salt Stress

Frontiers in Plant Science ◽

10.3389/fpls.2021.697324 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jing Gao ◽

Paula J. M. van Kleeff ◽

Mark H. de Boer ◽

Alexander Erban ◽

Joachim Kopka ◽

...

Keyword(s):

Salt Stress ◽

Ion Homeostasis ◽

Nacl Stress ◽

Stress Adaptation ◽

Metabolome Analysis ◽

Group 14 ◽

Relative Growth ◽

Knockout Mutants ◽

Group Members

Salinity is one of the major abiotic stresses that limits agricultural productivity worldwide. Many proteins with defined functions in salt stress adaptation are controlled through interactions with members of the 14-3-3 family. In the present study, we generated three 14-3-3 quadruple knockout mutants (qKOs: klpc, klun, and unpc) to study the role of six non-epsilon group 14-3-3 proteins for salt stress adaptation. The relative growth inhibition under 100 mM of NaCl stress was the same for wild-type (Wt) and qKOs, but the accumulation of Na+ in the shoots of klpc was significantly lower than that in Wt. This difference correlated with the higher expression of the HKT1 gene in klpc. Considering the regulatory role of 14-3-3 proteins in metabolism and the effect of salt stress on metabolite accumulation, we analyzed the effect of a 24-h salt treatment on the root metabolome of nutrient solution-grown genotypes. The results indicated that the klpc mutant had metabolome responses that were different from those of Wt. Notably, the reducing sugars, glucose and fructose, were lower in klpc under control and salt stress. On the other hand, their phosphorylated forms, glucose-6P and fructose-6P, were lower under salt stress as compared to Wt. This study provided insight into the functions of the 14-3-3 proteins from non-epsilon group members. In summary, it was found that these proteins control ion homeostasis and metabolite composition under salt stress conditions and non-stressed conditions. The analyses of single, double, and triple mutants that modify subsets from the most effective qKO mutant (klpc) may also reveal the potential redundancy for the observed phenotypes.

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