Salinity is a major abiotic stress for crop plants that cause reduced food production. The application of plant growth-promoting microorganisms can improve the adaptability of plants to biotic and abiotic stresses. Therefore, in the current study, we aimed to enhance the mitigation effects of artificially applied rhizobacterium Klebsiella variicola AY13 on salinity stress in Trifolium repens L. The results suggested that AY13 innately produced indole-3-acetic acid and accelerated the morphological adaptation of T. repens to salt stress conditions. Furthermore, AY13 promotes a Trp-dependent pathway for indole-3-acetic acid (IAA) production, as adding L-tryptophan (L-Trp) increased IAA production in pure culture. AY13 improved plant growth by maintaining relative water content and minimizing water loss in excised leaves. Moreover, AY13 inoculation significantly reduced the endogenous levels of abscisic acid and antioxidants such as glutathione and catalase. These results suggest that AY13 plays a crucial role in reprogramming stress-related metabolism and enhancing plant stress tolerance.

Abstract
Introduction
Materials and Methods
    1. Salt resistance of bacterial strains
    2. Plant materials
    3. Quantification of indole-3-acetic acid
    4. Abscisic acid quantification
    5. Glutathione (GSH) and catalase (CAT) analysis
    6. Statistical analysis
Results and Discussion
    1. AY13-induced salt stress resistance and IAA production
    2. Plant morphological characteristics
    3. Analysis of RWC and ELWL (%)
    4. Abscisic acid quantification
    5. Quantification of reduced GSH and catalase
Acknowledgments
References

• Eun-Jung Park(Researcher, Department of Applied Biosciences, Kyungpook National University)
• Sang-Mo Kang(Researcher professor, Department of Applied Biosciences, Kyungpook National University)
• Arjun Adhikari(Researcher professor, Department of Applied Biosciences, Kyungpook National University)
• Bo-Ram Choi(Researcher, National Institute of Animal Science, Rural Development Administration (RDA),)
• Ki-Young Kim(Researcher, National Institute of Animal Science, Rural Development Administration (RDA),)
• Seok-Min Lee(Researcher, Gyeonsangnam-Do Agricultural Research & Extension Services)
• In-Jung Lee(Professor, Department of Applied Biosciences, Kyungpook National University) Corresponding author