Efficiency of a novel endophytic fungus based biofertilizer in enhancing rice productivity and reducing the chemical fertilizer use in saline and non-saline coastal regions of Bangladesh
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.
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)
Alfi Anjum Rashid, Samiur Rahim, Shakila Nargis Khan et al.· Plant Tissue Culture and Bio...· 0 citations
The Fukushima nuclear accident caused widespread radiocesium contamination, and subsequent decontamination reduced soil fertility by removing nutrient-rich topsoil. Although biological amendments have been widely investigated for soil improvement, their potential to restore crop productivity in decontaminated Fukushima soils remains poorly understood. This study evaluated a Bacillus-based biofertilizer (Yume-Bio) and an Aspergillus fermentation product (kouji) as biological amendments for restoring crop productivity in decontaminated soils. Pot and field experiments were conducted to assess their effects on the growth, mineral nutrition, and seed yield of Perilla frutescens grown in decontaminated Fukushima soils. In pot experiments, Yume-Bio showed no significant effects on plant growth, although slight root improvement was observed. In contrast, application of kouji alone or in combination with Yume-Bio significantly enhanced plant growth, increasing leaf number by 112% and improving biomass production. Nutrient accumulation was also promoted, with total N and Fe increasing by 170% and 194%, respectively. In field experiments at two sites in Fukushima, treatment effects were limited and generally non-significant. These results indicate that kouji has potential to enhance plant growth under controlled conditions, while the effectiveness of biological amendments under field conditions remains site-dependent, highlighting the need to optimize application strategies under heterogeneous soil conditions.
Salem Djedidi, Hideki Ishii, Takehisa Kumagai et al.· Crops· 0 citations
Soil salinization severely restricts seed germination, seedling establishment, and vegetative growth in key crops such as tomato (
Solanum lycopersicum
L.) and wheat (
Triticum aestivum
L.). Endophytic fungi from extreme environments are promising biostimulants to alleviate salinity stress, yet systematic assessments of isolates from hypersaline coastal ecosystems remain scarce. Here, we evaluated 28 endophytic fungal isolates from saline coastal ecosystems of the southeastern Iberian Peninsula using a four-stage pipeline: (i)
in vitro
characterization of salinity and temperature tolerance, (ii) germination bioassays under increasing NaCl gradients, (iii) seedling development under saline stress in controlled-environment pot experiments, and (iv) antioxidant enzyme profiling (POD, CAT, SOD) in both crops.
In vitro
screening revealed broad phenotypic diversity driven by a significant isolate × temperature × NaCl interaction, resolving two functional superclusters: a thermotolerant group led by
Sordaria fimicola
(BC05, BC06) with generalist thermal plasticity, and a stress-sensitive mesophilic group including several
Trichoderma
isolates, with BC47 (
Nothophoma gossypiicola
) emerging as a halotolerant specialist. Fungal inoculation significantly modulated germination, with responses strongly dependent on crop species, salinity level, and endophyte identity. In tomato, isolates BC06 (
S. fimicola)
, BC17 (
Clarireedia
sp.), BC47, and BC52 (
N. gossypiicola
) maintained radicle emergence at 100 mM NaCl, whereas in wheat BC06 was the only isolate capable of overcoming complete germination inhibition at 300 mM NaCl, markedly extending the osmotic tolerance limit of the species. Under saline pot conditions, inoculation enhanced tomato leaf area by up to 60% and root dry weight by up to 340%, while wheat responses were mostly neutral or negative, with BC24 (
Trichoderma gamsii)
as the sole shoot biomass enhancer (+58.1%) and BC50 (
T. saturnisporum
) uniquely improving the Dickson Quality Index. Antioxidant enzyme activities displayed contrasting, host- and context-specific patterns between crops. Overall, this study provides the first evidence of
S. fimicola, Clarireedia narcissi
, and
N. gossypiicola
as effective fungal biostimulants under saline stress and highlights the biotechnological potential of non-conventional endophytes from extreme coastal environments as a basis for the rational selection of sustainable bioinoculants for salt-affected agricultural systems.
Victoria Huertas, F. Diánez, Carmen Palazón et al.· Frontiers in Plant Science· 0 citations
Glycyrrhiza uralensis
is an ecologically and economically important medicinal species for saline-alkali land restoration in arid northwest China. Nevertheless, excessive soil salinity, alkalinity and nutrient deficiency substantially restrict its growth and degrade medicinal quality. Microbial inoculation serves as a promising strategy to alleviate salt-alkali stress, yet the field stability and rhizosphere regulatory mechanisms of inoculants under diverse cultivation regimes remain poorly understood, limiting their field application. Building on our prior strain screening and preliminary field validation, this study utilized a composite inoculant containing
Pseudomonas silesiensis
,
Arthrobacter
sp. GCG3 and
Rhizobium
sp. DG1, and investigated its effects on
G. uralensis
growth, bioactive metabolites, rhizosphere soil properties and microbial communities under three field viable cultivation scenarios (direct seeding and seedling transplanting in moderately saline-alkali soil, seedling transplanting in severely saline-alkali soil) with respective tailored fertilization, planting densities and inoculation schedules. The results revealed that under all scenarios, the inoculation induced an increasing trend in the root dry weight and bioactive compound accumulation, with markedly higher dry root weight in seedling transplanting scenarios (101.68%, moderately saline-alkali soil; 53.96%, severely saline-alkali soil,
P
< 0.05). Glycyrrhizic acid contents per plant rose by 57.32, 106.11 and 6.56%, while those of liquiritin rose by 42.50, 177.24 and 42.34%, respectively. The inoculant barely altered rhizosphere pH and soluble salt contents, yet universally regulated rhizosphere nutrient pools, which were reflected in a uniform reduction of nitrate nitrogen and scenario-specific shifts in other available nutrients as well as soil organic matter. High-throughput sequencing verified that this inoculant could reshape the rhizosphere microbial community structure of
G. uralensis
; across all scenarios, the relative abundance of pathogenic
Fusarium
significantly decreased, and indigenous beneficial bacteria and fungi were enriched. This inoculant exhibited stable growth-promoting effects across all cultivation regimes. The combined application of microbial inoculation and seedling transplanting is therefore recommended for large-scale and high-quality cultivation of
G. uralensis
in moderately saline-alkali soils of arid northwestern China, as this integrated practice maximizes plant growth, medicinal compound accumulation, and rhizosphere microenvironment optimization.
Qihao Guo, Jun Zhang, Xin Li et al.· Environmental Microbiome· 0 citations
Soil salinity and alkalinity present critical constraints to agricultural productivity, particularly in arid and semi-arid regions. This study characterized the rhizospheric microbial communities and isolated halotolerant plant growth-promoting rhizobacteria (HT-PGPR) from rice (Oryza sativa L.) and wheat (Triticum aestivum L.) cultivated in sodic soils with variable salinity levels. Soil physicochemical and biochemical analyses revealed significant correlations between soil sodium content and microbial activity parameters. Serial dilution and selective media techniques identified bacterial and fungal populations with varying tolerance to sodium chloride (0.5-5%), sodium carbonate (1-2.5%), and sodium bicarbonate (1-2.5%) concentrations. Rice rhizosphere exhibited higher bacterial populations (19.1-38.3 × 104 cfu/g) compared to wheat (10.5-65.2 × 104 cfu/g), while wheat showed increased fungal diversity (17.5-80.5 × 103 MPN/g). Among the isolates, 30–40% demonstrated tolerance to 5% NaCl, indicating potential as HT-PGPR candidates for biofortification and saline soil amelioration. Microbial biomass carbon and nitrogen showed positive associations with soil enzyme activities, particularly dehydrogenase (14.25-25.34 µg TPF/g/day) and alkaline phosphatase (9.7-15.6 µg PNP/g/day) in rice. These findings suggest that selected halotolerant isolates possess multifunctional traits including salt tolerance and potential nutrient-solubilizing capacity, making them promising candidates for biofertilizer development and sustainable agriculture in salt-affected regions.
H. Dixit, Ranjan Singh, Sanjay Arora et al.· Journal of Soil and Water Co...· 0 citations
Soil salinity remains a major abiotic factor limiting agricultural productivity worldwide, with the situation worsening in parts of Maharashtra, particularly Karad Taluka. This study examined saline soils from various locations within Karad, assessing their physicochemical properties and isolating indigenous halotolerant bacterial strains that exhibit plant growthpromoting rhizobacterial (PGPR) traits. The soil analysis revealed highly alkaline pH levels (8.8-9.4), elevated sodium concentrations, and deficiencies in organic carbon, nitrogen, and micronutrients. Five halotolerant bacterial isolates (Ko1, Va1, Be1, Vm1, and At1) were obtained and evaluated for PGPR activities such as phosphate and potassium solubilization, nitrogen fixation, indole-3-acetic acid (IAA) production, and siderophore synthesis. All isolates demonstrated positive results in phosphate and potassium solubilization, nitrogen fixation, and IAA production, with four also producing siderophores. Notably, isolates Be1, Vm1, and At1 showed strong performance across multiple traits, highlighting their potential as bioinoculant candidates. These findings suggest that native halotolerant PGPR strains from Karad Taluka could enhance soil fertility, improve nutrient uptake, and support plant growth in saline conditions. Future research including field trials and molecular characterization could facilitate the development of environmentally sustainable microbial formulations for saline agriculture.
Priyadarshani A. Patil, Aparna G Pathade, Girish R. Pathade· Nature Environment and Pollu...· 0 citations