ORIGINAL RESEARCH article

Front. Plant Sci.

Sec. Plant Symbiotic Interactions

Volume 16 - 2025 | doi: 10.3389/fpls.2025.1610707

This article is part of the Research TopicIntegrative Techniques to Alleviate Abiotic Stress in Plants Using Plant Growth Promoting Bacteria and Fungi: Mechanisms, Interactions, and ApplicationsView all 6 articles

Biofilmed Multifarious Rhizobacterial Isolates of Tomato Rhizosphere of North-Western Himalayas Promote Plant Growth in Tomato

Provisionally accepted
Shubham KaundalShubham Kaundal1*Neerja RanaNeerja Rana1Yashwant KumarYashwant Kumar2Saleh S AlhewairiniSaleh S Alhewairini3*JAYANTHI BARASARATHIJAYANTHI BARASARATHI4Farah Farhanah HaronFarah Farhanah Haron5Nazih Yacer RebouhNazih Yacer Rebouh6
  • 1Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Himachal Pradesh, India
  • 2Central Research Institute Kasauli, Kasauli, Himachal Pradesh, India
  • 3Qassim University, Buraidah, Al-Qassim, Saudi Arabia
  • 4INTI International University, Nilai, Negeri Sembilan Darul Khusus, Malaysia
  • 5Malaysian Agricultural Research and Development Institute (MARDI), Serdang, Malaysia
  • 6RUDN University, Moscow, Russia

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Background: Tomato production is often limited by poor soil health and nutrient deficits, which lower crop productivity. Plant growth-promoting rhizobacteria (PGPR) provide a sustainable approach for improving plant development and soil fertility.The objectives of this study were to: (1) isolate and screen PGPR from the rhizosphere soil of tomato-growing regions in Himachal Pradesh, India; (2) evaluate the selected PGPR for biofilm production; (3) characterize and molecularly identify the biofilmproducing isolates; and (4) assess their efficacy in enhancing tomato plant growth.Methods: Forty bacterial isolates were collected from soils in Dharon Ki Dhar, Shillai, Balh, and Berthin and tested for PGPR characteristics. These included phosphate solubilization, nitrogen fixation, and the production of hydrogen cyanide, ammonia, and indole-3-acetic acid (IAA). Siderophore production and biofilm formation were also assessed. The most potent biofilm-producing isolates were identified using 16S rDNA sequencing.Results: Among the isolates, 28 solubilized phosphate (up to 91.2% with MB-7), 26 fixed nitrogen, 18 produced hydrogen cyanide, and 16 produced ammonia. All isolates produced IAA, with MB-7 and BB-3 producing the highest quantities (89.1 µg/mL and 85.1 µg/mL, respectively). BB-3 exhibited the highest percentage of siderophore production (86.2%). BB-3 and MB-7 were potent biofilm producers. Molecular analysis identified BB-3 as Brucella rhizosphereae and MB-7 as Delftia lacustris. Inoculation with D. lacustris greatly enhanced tomato plant growth: plant height increased by 49.14%, shoot fresh weight increased by 32.47%, and root length increased by 45.00% as compared to uninoculated control.Delftia lacustris shows significant potential as a bio-inoculant for increasing tomato plant growth and can potentially be used effectively in sustainable agriculture approaches.

Keywords: Ammonia, Biofilm-producing, HCN, Indole acetic acid, PGPR, P solubilization

Received: 12 Apr 2025; Accepted: 29 May 2025.

Copyright: © 2025 Kaundal, Rana, Kumar, Alhewairini, BARASARATHI, Haron and Rebouh. 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:
Shubham Kaundal, Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, 173230, Himachal Pradesh, India
Saleh S Alhewairini, Qassim University, Buraidah, 52571, Al-Qassim, Saudi Arabia

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