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ORIGINAL RESEARCH article

Front. Plant Sci.
Sec. Plant Abiotic Stress
Volume 16 - 2025 | doi: 10.3389/fpls.2025.1545865

Physiological and molecular mechanisms of exogenous salicylic acid in enhancing salt tolerance in tobacco seedlings by regulating antioxidant defence system and gene expression

Provisionally accepted
Xiliang Song Xiliang Song 1*Jian Chen Jian Chen 2Can Xu Can Xu 3Xianjie Cai Xianjie Cai 2Wenjing Song Wenjing Song 4Aixia Chang Aixia Chang 4Yu Zhang Yu Zhang 4Chenggang Luo Chenggang Luo 4
  • 1 College of Resources and Environment, Shandong Agricultural University, Tai'an, China
  • 2 Shanghai Tobacco Group Co., Ltd, Shanghai, China
  • 3 Dezhou University, Dezhou, Shandong, China
  • 4 Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong Province, China

The final, formatted version of the article will be published soon.

    Salt stress has emerged as a predominant abiotic factor that jeopardizes global crop growth and yield. The plant hormone salicylic acid (SA) has notable potential in mitigating salt toxicity, yet its mechanism in enhancing the salinity tolerance of tobacco plants is not well explored. This study aimed to assess the potential benefits of exogenous SA application (1.0 mM) on tobacco seedlings subjected to saline soil conditions. The foliar spray of SA partially mitigated these salt-induced effects, as evidenced by a reduction of malondialdehyde content, and improvements of leaf K+/Na+ ratios, pigment biosynthesis, and electron transport efficiency under NaCl stress. Additionally, SA increased the contents of total phenolic compound and soluble protein by 16.2% and 28.7% to alleviate NaCl-induced oxidative damage. Under salt stressed conditions, the activities of antioxidant enzymes, including superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase increased by 4.2%~14.4% in SA sprayed tobacco seedlings. Exogenous SA also increased ascorbate and glutathione levels and reduced their reduced forms by increasing the activities of glutathione reductase, ascorbate peroxidase, monodehydroascorbate reductase and dehydroascorbate reductase. qRT‒PCR analysis revealed that the key genes regulating SA biosynthesis, carbon assimilation, the antioxidant system and the ascorbate‒glutathione cycle were activated by SA under conditions of salt stress. Our study elucidates the physiological and molecular mechanisms of exogenous SA in enhancing plant salt tolerance and provides a practical basis for crop improvement in saline environments.

    Keywords: Soil salinity, iron toxicity, Oxidative damage, Salicylic Acid, salt tolerance

    Received: 16 Dec 2024; Accepted: 07 Jan 2025.

    Copyright: © 2025 Song, Chen, Xu, Cai, Song, Chang, Zhang and Luo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Xiliang Song, College of Resources and Environment, Shandong Agricultural University, Tai'an, China

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.