Jun 2026· Plant Tissue Culture and Biotechnology· 0 citations· 31 references
Abstract
Global climate change poses a major threat to food security by reducing crop productivity, particularly through soil salinization. Plant growth-promoting rhizobacteria (PGPR) offer a climate-smart and sustainable solution to mitigate salinity stress and enhance crop yield. This study investigated four potent endophytic PGPR: Enterobacter cloacae, Achromobacter xylosoxidans, Bacillus aryabhattai, and Stenotrophomonas pavanii, previously isolated from rice endophytes grown in coastal agricultural lands of Bangladesh. These strains were screened for plant growth-promoting traits and tested on the salt-sensitive rice cultivar BRRI-28 under 200 mM NaCl stress. PGPR-treated plants exhibited higher chlorophyll, carbohydrate, and protein levels, along with increased proline accumulation, indicating improved photosynthetic and metabolic activity. Reduced malondialdehyde (MDA) levels indicated enhanced membrane stability. Gene expression analysis revealed upregulation of salt-tolerance genes (GIG, BZ8, SOS1), while eEF-1α expression remained stable. These findings demonstrate that PGPR-mediated enhancement of salt tolerance in Oryza sativa is associated with the upregulation of key salt-responsive genes, consistent with a targeted plant–microbe interaction that may contribute to improved salinity tolerance.
Plant Tissue Cult. & Biotech. 36(1): 91-105, 2026 (June)
Salt-tolerant rhizosphere microorganisms with multiple plant growth–promoting (PGP) traits represent cost-effective biological inoculants for enhancing plant tolerance to abiotic stress.
In this study, a salt-tolerant fungal strain, SZ01, was isolated from the rhizosphere of
Clematis chinensis
using PDA medium supplemented with 1% NaCl and identified as
Trichoderma compactum
based on morphological and molecular analyses. SZ01 tolerated NaCl concentrations up to 9%. Functional characterization revealed that SZ01 exhibited potassium solubilization, nitrogen fixation potential, and siderophore production, although it lacked the ability to solubilize organic or inorganic phosphorus. Pot experiments demonstrated that under salt stress, inoculation with SZ01 spore suspension significantly increased the fresh and dry weights of underground tissues, reduced Malondialdehyde (MDA) accumulation, and enhanced soluble sugar and proline contents compared with non-inoculated controls, indicating effective mitigation of salt-induced physiological damage. Transcriptomic analysis of
C. chinensis
leaves further showed that SZ01 treatment triggered extensive transcriptional reprogramming, particularly through modulation of MAPK and metabolic pathways, thereby optimizing stress-responsive gene expression. Secondary metabolite profiling of SZ01 under salt stress revealed the accumulation of chlorine-containing molecules potentially contributing to plant growth promotion.
These findings highlight the potential of SZ01 as a microbial inoculant to promote plant growth and productivity in saline–alkaline environments, with implications for both medicinal and agricultural crop production.
Soil salinity severely constrains agricultural productivity worldwide, particularly affecting salt-sensitive crops such as maize (Zea mays L.) at early developmental stages. Plant growth-promoting rhizobacteria (PGPR) have emerged as a promising strategy to mitigate salinity stress; however, the underlying molecular mechanisms remain incompletely understood. In this study, we identified a salinity stress tolerance-promoting (SSTP) strain, Bacillus cereus isolate 74 (originally isolated from a salt-marshland environment), and investigated its role in enhancing salt tolerance in maize through integrated physiological and transcriptomic analyses. Phenotypic screening revealed that SSTP inoculation significantly improved plant growth parameters, chlorophyll content, and ionic balance under salinity stress. To elucidate the molecular basis of this response, RNA sequencing of maize roots was performed, identifying 307 high-confidence differentially expressed genes (DEGs). Functional enrichment analysis demonstrated that SSTP inoculation predominantly modulated pathways associated with oxidative stress mitigation, metabolic and catabolic processes, and cellular responses to chemical stimuli. Notably, genes involved in hydrogen peroxide detoxification, transport activity, and stress-responsive transcriptional regulation were significantly upregulated. These findings indicate that B. cereus isolate 74 enhances maize salt tolerance through coordinated regulation of antioxidant defense systems and metabolic reprogramming. This study provides novel insights into PGPR-mediated stress adaptation and highlights the potential application of SSTP strains in sustainable agriculture under saline conditions.
Maryam Zakavi, Hossein Askari, Mohammad Shahrooei· Microbiology Research· 0 citations
Soil salinity is a major abiotic stress that severely restricts crop productivity by disrupting ionic balance, inducing osmotic stress, and promoting oxidative damage. Black gram (Vigna mungo L.), an important pulse crop, is highly sensitive to salinity, resulting in reduced growth, physiological performance, and yield. The present study evaluated the efficacy of a compatible multi-strain HPGPB consortium comprising MKM3 (Halobacillus marinus), MKM4 (Halobacillus halophilus), and MKM11 (Halobacillus halophilus) in enhancing salinity tolerance in two black gram varieties (VBN8 and VBN11) under greenhouse conditions. Plants were subjected to 50 and 100 mM NaCl stress, with and without consortium inoculation, in a completely randomized design. Salinity stress significantly reduced plant growth, photosynthetic pigments, biomass, nutrient uptake, and grain yield, while increasing Na+ accumulation, lipid peroxidation, and osmotic stress markers. Consortium inoculation effectively mitigated these adverse effects by improving plant height, root development, biomass, and grain yield by up to 46 and 38%, respectively, under saline conditions. Consortium-inoculated plants exhibited improved photosynthetic performance, enhanced nutrient uptake and ionic balance, reduced Na+ accumulation and malondialdehyde content, and increased activities of antioxidant enzymes, indicating enhanced salinity tolerance. Among the tested varieties, VBN11 exhibited greater salinity tolerance and a stronger response to consortium inoculation than VBN8. Rhizosphere metagenomic analysis revealed consortium-associated shifts in microbial community structure under saline conditions. Collectively, the results demonstrate that the HPGPB consortium enhances salinity tolerance through coordinated physiological, biochemical, and microbiome-associated mechanisms. These findings highlight the potential of HPGPB consortia as sustainable bioinoculants for improving black gram productivity in salt-affected agroecosystems.
Daniel Raphael, Theivasigamani Parthasarathi· Frontiers in Microbiology· 0 citations
Enhanced soil salinity is a major constraint to rice production in the coastal regions of Bangladesh. Salinity stress impairs nutrient uptake and induces ionic toxicity and osmotic stress, while excessive use of chemical fertilizers degrades soil health and causes environmental pollution. A novel salt-tolerant endophytic fungus, Aspergillus welwitschiae Ocstreb1, isolated from the halophytic wild rice Oryza coarctata, exhibited multiple plant growth–promoting traits under both non-saline and 900 mM salt-stress conditions in vitro. These findings suggest that Ocstreb1-based biofertilizer could serve as an eco-friendly and cost-effective alternative to enhance rice productivity under saline conditions. In this experiment, the biofertilizer was prepared using fungal spores produced on wheat bran and subsequently mixed with talcum powder as a carrier. Field trials were conducted following a randomized complete block design (RCBD), incorporating different levels of chemical fertilizer application (0%, 80%, and 100% of the BRRI-recommended NPKSZn rates) in both biofertilizer-treated and untreated plants. Compared with the 100% chemical fertilizer treatment, the combined application of biofertilizer and 80% chemical fertilizer resulted in a comparable yield in Barguna and increased yield of 196.6 kg ha⁻¹ in Satkhira. Profitability analysis showed that this treatment provided an additional economic benefit of USD 48–68 ha⁻¹ over the 100% chemical fertilizer treatment. Moreover, fumonisin B1 levels in grains from biofertilizer-treated plants were negligible. In conclusion, commercial production of this biofertilizer will pave the way for enhancing rice yield with less use of chemical fertilizer while promoting sustainable agricultural practice particularly in areas affected by salinity stress.
Amit Chowdhury, J. Bhattacharya, Md. Iyasir Arafat et al.· Discover Agriculture· 0 citations
Soil salinization increasingly threatens global food security, and potato (Solanum tuberosum L.), a moderately salt-sensitive crop, is particularly vulnerable to saline soils. Plant growth-promoting rhizobacteria (PGPR) offer a promising strategy to improve crop performance, yet how PGPR interact with native microorganisms to enhance potato salt tolerance remains poorly understood. In this study, we identified a desert-derived PGPR strain, Ensifer sp. SA403, which substantially enhanced potato performance under high salinity across sterile, non-sterile and field conditions. Physiologically, inoculation with SA403 reduced shoot Na⁺ accumulation and increased the K⁺/Na⁺ ratio; notably, these effects were markedly stronger in non-sterile substrates than under sterile conditions, indicating that SA403-mediated ion homeostasis relies on cooperation with the resident microbiota rather than on the strain acting alone. Metagenomic profiling indicated that SA403 strain reshaped rhizosphere communities, significantly enriching beneficial taxa such as Priestia and Bradyrhizobium, and upregulated functional pathways involved in glutathione and sulfur metabolism. Furthermore, host transcriptomic analyses showed that SA403 modulated plant responses to salt stress, with differentially expressed genes enriched in jasmonic acid signaling, ethanolamine metabolism and amino-acid biosynthesis pathways. Field trials on saline soils confirmed that SA403 significantly increased seedling emergence and tuber weight. Together, our results demonstrate that SA403 functions as a biological mediator that optimizes rhizosphere microecology and coordinates ion balance and host signaling to enhance potato salt tolerance. These findings support the potential of SA403 as a robust PGPR-based tool for sustainable potato production on saline soils.
Yuxiao Zeng, Qian Tao, Jia-Hui Fan et al.· Microbiology Research· 0 citations
Soil salinisation severely constrains crop production. Legumes rely on rhizobial symbiosis for sustainable nitrogen acquisition. Although salinity is known to impair nodulation and nitrogen fixation, how symbiosis influences plant tolerance to salt stress remains unclear. In this study, we integrate physiological, biochemical, transcriptomic, ionomic, and metabolomic analyses to investigate the role of rhizobial symbiosis in salinity tolerance in Vicia sativa (common vetch) and Pisum sativum (pea). In both species, nodulated plants exhibited markedly enhanced survival and grain production under prolonged salt stress compared with nitrogen-fertilised (N-fed) controls. Under moderate salinity, nodulation helped maintain water status and stomatal conductance, reduced Na+ accumulation while improving K+ retention, and attenuated osmotic and oxidative stress, as evidenced by lower proline and malondialdehyde levels. Transcriptomic profiles in vetch revealed that symbiosis is associated with changes in the plant responses toward growth and microbial signalling, reducing the strong activation of stress pathways that typically occurs in non-nodulated plants. Ionomic and metabolomic data further showed that nodulated plants preserve nutrient balance and maintain a more stable carbon-nitrogen metabolism under salinity. These findings highlight the potential of Rhizobium inoculation to enhance crop resilience in salt-affected agroecosystems and demonstrate that symbiosis correlates with a more efficient and physiologically moderated acclimation to salinity in legumes.
María Isabel López-Román, L. Zurita, Cristina Castaño-Herrero et al.· Plant, Cell and Environment· 0 citations