Halophilic rhizobacteria promote growth, physiology and salinity tolerance in Sesamum indicum L. grown under salt stress

IntroductionSalt stress is a major global issue that negatively affects plant growth and physiological processes. Plant growth-promoting rhizobacteria (PGPR) are known to alleviate salt stress and promote plant growth. This study aimed to isolate and characterize salt-tolerant PGPR from salinity-aff...

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Main Authors: Dharman Sridhar, Saleh S. Alheswairini, Jayanthi Barasarathi, Hesham Ali El Enshasy, Sundaram Lalitha, Sajad Hussain Mir, S. Nithyapriya, Riyaz Sayyed
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-05-01
Series:Frontiers in Microbiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2025.1590854/full
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author Dharman Sridhar
Saleh S. Alheswairini
Jayanthi Barasarathi
Hesham Ali El Enshasy
Hesham Ali El Enshasy
Sundaram Lalitha
Sajad Hussain Mir
S. Nithyapriya
Riyaz Sayyed
author_facet Dharman Sridhar
Saleh S. Alheswairini
Jayanthi Barasarathi
Hesham Ali El Enshasy
Hesham Ali El Enshasy
Sundaram Lalitha
Sajad Hussain Mir
S. Nithyapriya
Riyaz Sayyed
author_sort Dharman Sridhar
collection DOAJ
description IntroductionSalt stress is a major global issue that negatively affects plant growth and physiological processes. Plant growth-promoting rhizobacteria (PGPR) are known to alleviate salt stress and promote plant growth. This study aimed to isolate and characterize salt-tolerant PGPR from salinity-affected soils in Tamil Nadu, India, and assess their potential to enhance growth and salt tolerance in sesame (Sesamum indicum L.).MethodsSalt-tolerant PGPR were isolated and screened for plant growth-promoting traits. One isolate, designated PAS1, demonstrated significant capabilities, including the production of indole-3-acetic acid (IAA; 48.56 μg ml−1), siderophore production (89.20 ± 0.65%), phosphate solubilization (7.8 mm zone of clearance), ammonia, and hydrogen cyanide (HCN) production. PAS1 was identified as Bacillus flexus. Sesame plants were inoculated with B. flexus and grown under different salt concentrations (0, 100, and 200 mM NaCl) for 45 days.ResultsInoculation with B. flexus significantly improved the biochemical parameters of sesame plants under salt stress, including increased chlorophyll content (4.4 mg g−1), proline (0.0017 mg g−1), soluble sugars (61.34 mg g−1), amino acids (1.10 mg g−1), and proteins (3.31 mg g−1). Additionally, antioxidant enzyme activities were enhanced, as indicated by DPPH scavenging activity (60.25%), superoxide dismutase (231.29 U mg g−1 protein), peroxidase (6.21 U mg g−1 protein), catalase (3.38 U mg g−1 protein), and a reduction in malondialdehyde (23.32 μmol g−1).DiscussionThe study demonstrates that inoculation with salt-tolerant B. flexus can effectively improve sesame plant growth and enhance tolerance to salt stress. These findings suggest that halo-tolerant PGPR strains like B. flexus could serve as promising biofertilizers to improve crop productivity in salt-affected agricultural soils.
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spelling doaj-art-77e3730b4b6e46c195d2d63ac4b2cdd92025-08-20T03:49:35ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2025-05-011610.3389/fmicb.2025.15908541590854Halophilic rhizobacteria promote growth, physiology and salinity tolerance in Sesamum indicum L. grown under salt stressDharman Sridhar0Saleh S. Alheswairini1Jayanthi Barasarathi2Hesham Ali El Enshasy3Hesham Ali El Enshasy4Sundaram Lalitha5Sajad Hussain Mir6S. Nithyapriya7Riyaz Sayyed8Department of Botany, School of Life Sciences, Periyar University, Salem, IndiaDepartment of Plant Protection, College of Agriculture and Food, Qassim University, Buraidah, Saudi ArabiaFaculty of Health and Life Sciences (FHLS), Inti International University, Nilai, MalaysiaInnovation Centre in Agritechnology for Advanced Bioprocessing (ICA), Universiti Teknologi Malaysia, Johor Bahru, MalaysiaFaculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia (UTM), Johor Bahru, MalaysiaPG and Research Department of Botany, Padmavani Arts and Science College for Women, Salem, IndiaKey Laboratory of Integrated Crop Pest Management of Anhui Province, College of Plant Protection, Anhui Agricultural University, Hefei, Anhui, ChinaPG and Research Department of Botany, Padmavani Arts and Science College for Women, Salem, IndiaDepartment of Biological Sciences and Chemistry, University of Nizwa, Nizwa, OmanIntroductionSalt stress is a major global issue that negatively affects plant growth and physiological processes. Plant growth-promoting rhizobacteria (PGPR) are known to alleviate salt stress and promote plant growth. This study aimed to isolate and characterize salt-tolerant PGPR from salinity-affected soils in Tamil Nadu, India, and assess their potential to enhance growth and salt tolerance in sesame (Sesamum indicum L.).MethodsSalt-tolerant PGPR were isolated and screened for plant growth-promoting traits. One isolate, designated PAS1, demonstrated significant capabilities, including the production of indole-3-acetic acid (IAA; 48.56 μg ml−1), siderophore production (89.20 ± 0.65%), phosphate solubilization (7.8 mm zone of clearance), ammonia, and hydrogen cyanide (HCN) production. PAS1 was identified as Bacillus flexus. Sesame plants were inoculated with B. flexus and grown under different salt concentrations (0, 100, and 200 mM NaCl) for 45 days.ResultsInoculation with B. flexus significantly improved the biochemical parameters of sesame plants under salt stress, including increased chlorophyll content (4.4 mg g−1), proline (0.0017 mg g−1), soluble sugars (61.34 mg g−1), amino acids (1.10 mg g−1), and proteins (3.31 mg g−1). Additionally, antioxidant enzyme activities were enhanced, as indicated by DPPH scavenging activity (60.25%), superoxide dismutase (231.29 U mg g−1 protein), peroxidase (6.21 U mg g−1 protein), catalase (3.38 U mg g−1 protein), and a reduction in malondialdehyde (23.32 μmol g−1).DiscussionThe study demonstrates that inoculation with salt-tolerant B. flexus can effectively improve sesame plant growth and enhance tolerance to salt stress. These findings suggest that halo-tolerant PGPR strains like B. flexus could serve as promising biofertilizers to improve crop productivity in salt-affected agricultural soils.https://www.frontiersin.org/articles/10.3389/fmicb.2025.1590854/fullPGPR traitsB. flexusmetabolitesantioxidantsalt stress
spellingShingle Dharman Sridhar
Saleh S. Alheswairini
Jayanthi Barasarathi
Hesham Ali El Enshasy
Hesham Ali El Enshasy
Sundaram Lalitha
Sajad Hussain Mir
S. Nithyapriya
Riyaz Sayyed
Halophilic rhizobacteria promote growth, physiology and salinity tolerance in Sesamum indicum L. grown under salt stress
Frontiers in Microbiology
PGPR traits
B. flexus
metabolites
antioxidant
salt stress
title Halophilic rhizobacteria promote growth, physiology and salinity tolerance in Sesamum indicum L. grown under salt stress
title_full Halophilic rhizobacteria promote growth, physiology and salinity tolerance in Sesamum indicum L. grown under salt stress
title_fullStr Halophilic rhizobacteria promote growth, physiology and salinity tolerance in Sesamum indicum L. grown under salt stress
title_full_unstemmed Halophilic rhizobacteria promote growth, physiology and salinity tolerance in Sesamum indicum L. grown under salt stress
title_short Halophilic rhizobacteria promote growth, physiology and salinity tolerance in Sesamum indicum L. grown under salt stress
title_sort halophilic rhizobacteria promote growth physiology and salinity tolerance in sesamum indicum l grown under salt stress
topic PGPR traits
B. flexus
metabolites
antioxidant
salt stress
url https://www.frontiersin.org/articles/10.3389/fmicb.2025.1590854/full
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