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ORIGINAL RESEARCH article

Front. Plant Sci.

Sec. Plant Symbiotic Interactions

Volume 16 - 2025 | doi: 10.3389/fpls.2025.1629184

This article is part of the Research TopicSymbiotic Interactions in Microbial-facilitated Vegetation Restoration and Agricultural ManagementView all 14 articles

Exploring the rhizospheric bacterial community of selected millets for plant growth promotion activity in tomato

Provisionally accepted
Anitha  SakthivelAnitha Sakthivel1Santhanalakshmi  BalasubramanianSanthanalakshmi Balasubramanian1JOSEPH SAHAYARAYAN  JESUDASSJOSEPH SAHAYARAYAN JESUDASS2Sivanandhan  GaneshanSivanandhan Ganeshan3Ravishankar  Ram ManiRavishankar Ram Mani4Soon  Woong ChangSoon Woong Chang5BALASUBRAMANI  RAVINDRANBALASUBRAMANI RAVINDRAN6*Santosh  ChokkakulaSantosh Chokkakula7Kapildev  GnanajothiKapildev Gnanajothi1
  • 1Bharathiar university, Coimbatore, India
  • 2Alagappa university, Karaikudi, India
  • 3Dhanalakshmi Srinivasan University, Tiruchirappalli, India
  • 4UCSI university, Cheras, Malaysia
  • 5Kyonggi university, Suwon, Republic of Korea
  • 6Kyonggi University, Suwon, Republic of Korea
  • 7Chungbuk National University Medical College, Cheonju, Republic of Korea

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

Millets are highly nutritious crops mostly cultivated in xeric regions of Asia and Africa. The specific agro-climatic characteristics of millets enable the rhizosphere to host diverse microorganisms that assist in the crop's progression under harsh weather conditions. This research work intends to evaluate the plant growth-promoting (PGP) potential of the rhizospheric microbes isolated from the soil of Panicum sumatrense and Eleusine coracana from Kunnanchala and Varagampadi, residing areas of Irulas Tribal Community located in the Attapadi Hills of Kerala and Tamil Nadu, respectively. A total of 53 bacterial isolates with unique colony morphology were initially subjected to the nitrogen fixation test. Twenty-six isolates that demonstrated positive results for nitrogen fixation were characterized for phosphate solubilization, ammonia, indole acetic acid (IAA), siderophore, hydrogen cyanide (HCN), and hydrolytic enzyme production, molecular characterization, and antagonistic activity against the common plant pathogens Fusarium oxysporum and Colletotrichum gloeosporioides. The principal component analysis revealed that SA1 (Staphylococcus gallinarum) and MS6 (Kosakonia sacchari) exhibited the highest values for IAA production (0.37 ± 0.015 mg/mL) and PSI (3.36 ± 0.03), respectively. MS3 (Bacillus velezensis) demonstrated the most promising results in antagonism (91.32 ± 0.57) and ammonia production (0.11±0.020 mg/mL). All the bacterial isolates exhibited a notable improvement in germination, shoot length, root length, and vigor index of Solanum lycopersicum. The most prominent results in germination studies were noted in K. sacchari (MS6), with the most pronounced effects, including a 100% germination rate, 2.58 ± 0.01 cm of shoot length, 7.61 ± 0.03 cm of root length, and a vigor index of 1019. The results of the invitro PGP traits are sufficient to support future tests on the promotion of growth invivo for these seven strains in a single or consortium.

Keywords: Antagonistic Activity, Millet, PGPR, plant growth promotion, rhizosphere

Received: 15 May 2025; Accepted: 01 Sep 2025.

Copyright: © 2025 Sakthivel, Balasubramanian, JESUDASS, Ganeshan, Mani, Chang, RAVINDRAN, Chokkakula and Gnanajothi. 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: BALASUBRAMANI RAVINDRAN, Kyonggi University, Suwon, Republic of Korea

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