ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Microbial Physiology and Metabolism
Bacterial Consortia Enhance Nutrient Uptakes and Molecular Response in Tomato Seedlings Under Alkaline Soil Stress: A Comparative Study
Provisionally accepted
Keerthana Rangasamy
Arabi Mohammed Saleh*- VIT University, Vellore, India
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Abstract: Nutrient deficiencies in alkaline soils (pH 7.9-8.5) frequently limit plant growth due to insufficient nutrient availability and uptake. This study investigated the effects of two bacterial strains, VITK-1 (Pseudomonas sp.) and VITK-3 (Burkholderia sp.), on nutrient absorption, growth, and gene expression in tomato (Solanum lycopersicum) seedlings grown in alkaline soil. Bacterial treatments were applied individually and as a consortium, and their ability to promote plant growth and nutrient solubility was evaluated. In vitro studies demonstrated the strains' ability to solubilize essential nutrients, generate extracellular enzymes, and exhibit a variety of Plant Growth-Promoting Rhizobacteria (PGPR) characteristics, with strong antagonistic activity against Fusarium oxysporum f.sp. lycopersici and Ralstonia solanacearum (35.7% - 76.5%). In vivo investigations revealed notable improvements in germination (73.3%), root and shoot development, and overall seedling vigor when compared to untreated controls. The bacterial consortium significantly improved protein (54.5%) and proline (69.5%) levels, antioxidant activity (50.7%), phenolic (60.9%), and flavonoid content (52.5%), and decreased carbohydrate accumulation. Furthermore, treated plants exhibited activation of nutrient-regulating genes (NRT2, PR-1, and AMT-1) associated with better root metabolism (improved 1.58 – 1.70 mg) and resilience to stress (GR-1 and DREB3). These results show the potential of PGPR inoculants, particularly consortia, as a promising strategy for improving nutrient uptake, biochemical characteristics, and stress tolerance in crops grown in alkaline soils.
Keywords: Alkaline stress, Bacterial consortia, enzyme activity, Gene Expression, seed germination
Received: 03 Nov 2025; Accepted: 16 Feb 2026.
Copyright: © 2026 Rangasamy and Saleh. 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: Arabi Mohammed Saleh
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