Exogenous γ-aminobutyric acid (GABA) mitigated salinity-induced impairments in mungbean plants by regulating their nitrogen metabolism and antioxidant potential

Abd Ullah; Iftikhar Ali; Javaria Noor; Fanjiang Zeng; Sami Bawazeer; Sayed M Eldin; Muhammad Ahsan Asghar; Hafiz Hassan Javed; Khansa Saleem; Sami Ullah; Haider Ali

doi:10.3389/fpls.2022.1081188

Exogenous γ-aminobutyric acid (GABA) mitigated salinity-induced impairments in mungbean plants by regulating their nitrogen metabolism and antioxidant potential

Front Plant Sci. 2023 Jan 18:13:1081188. doi: 10.3389/fpls.2022.1081188. eCollection 2022.

Authors

Abd Ullah^{1

2

3}, Iftikhar Ali^{4

5}, Javaria Noor⁶, Fanjiang Zeng^{1

2

3}, Sami Bawazeer⁷, Sayed M Eldin⁸, Muhammad Ahsan Asghar⁹, Hafiz Hassan Javed¹⁰, Khansa Saleem¹¹, Sami Ullah¹², Haider Ali⁴

Affiliations

¹ Xinjiang Key Laboratory of Desert Plant Root Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.
² Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, China.
³ University of Chinese Academy of Sciences, Beijing, China.
⁴ Center for Plant Sciences and Biodiversity, University of Swat, Charbagh Swat, Pakistan.
⁵ Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, United States.
⁶ Department of Botany, Islamia College University, Peshawar, Pakistan.
⁷ Umm Al-Qura University, Faculty of Pharmacy, Department of Pharmacognosy, Makkah, Saudi Arabia.
⁸ Center of Research, Faculty of Engineering, Future University in Egypt, New Cairo, Egypt.
⁹ Department of Biological Resources, Agricultural Institute, Centre for Agricultural Research, ELKH, 2 Brunszvik St. Martonvásár, Hungary.
¹⁰ College of Agronomy, Sichuan Agricultural University, Chengdu, China.
¹¹ Department of Horticultural Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan.
¹² Department of Botany, University of Peshawar, Peshawar, Pakistan.

Abstract

Background: Increasing soil salinization has a detrimental effect on agricultural productivity.Therefore, strategies are needed to induce salinity-tolerance in crop species for sustainable foodproduction. γ-aminobutyric acid (GABA) plays a key role in regulating plant salinity stresstolerance. However, it remains largely unknown how mungbean plants (Vigna radiata L.) respondto exogenous GABA under salinity stress.

Methods: Thus, we evaluated the effect of exogenous GABA (1.5 mM) on the growth and physiobiochemicalresponse mechanism of mungbean plants to saline stress (0-, 50-, and 100 mM [NaCland Na2SO4, at a 1:1 molar ratio]).

Results: Increased saline stress adversely affected mungbean plants' growth and metabolism. Forinstance, leaf-stem-root biomass (34- and 56%, 31- and 53%, and 27- and 56% under 50- and 100mM, respectively]) and chlorophyll concentrations declined. The carotenoid level increased (10%)at 50 mM and remained unaffected at 100 mM. Hydrogen peroxide (H2O2), malondialdehyde(MDA), osmolytes (soluble sugars, soluble proteins, proline), total phenolic content, andenzymatic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase(POD), glutathione reductase (GTR), and polyphenol oxidation (PPO) were significantlyincreased. In leaves, salinity caused a significant increase in Na+ concentration but a decrease inK+ concentration, resulting in a low K+/Na+ concentration (51- and 71% under 50- and 100- mMstress). Additionally, nitrogen concentration and the activities of nitrate reductase (NR) andglutamine synthetase (GS) decreased significantly. The reduction in glutamate synthase (GOGAT)activity was only significant (65%) at 100 mM stress. Exogenous GABA decreased Na+, H2O2,and MDA concentrations but enhanced photosynthetic pigments, K+ and K+/Na+ ratio, Nmetabolism, osmolytes, and enzymatic antioxidant activities, thus reducing salinity-associatedstress damages, resulting in improved growth and biomass.

Conclusion: Exogenous GABA may have improved the salinity tolerance of mungbean plants by maintaining their morpho-physiological responses and reducing the accumulation of harmfulsubstances under salinity. Future molecular studies can contribute to a better understanding of themolecular mechanisms by which GABA regulates mungbean salinity tolerance.

Keywords: Salinity; antioxidant mechanism; nitrogen metabolism; physiologicalmechanism; phytohormones; plant abiotic stress; plant growth regulators.

Grants and funding

The authors would like to thank the Deanship of Scientific Research at Umm Al-Qura Universityfor supporting this work by Grant Code: 22UQU4350073DSR09.