Novel halotolerant fungal endophytes from hypersaline coastal ecosystems as sustainable biostimulants for early growth performance of tomato and wheat under saline stress
Aug 2026· Frontiers in Plant Science· 0 citations· 152 references
TL;DR
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.
Abstract
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.
It is suggested 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
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
Increasing soil salinization severely threatens agricultural productivity in many coastal ecosystems and dryland regions. In this study, two halotolerant endophytic bacterial strains, Bacillus sp. CR-4 and Streptomyces sp. CR-7, was isolated from Catharanthus roseus collected from saline coastal areas and evaluated for its plant growth-promoting traits and salt stress-mitigation ability. The selected isolates displayed diverse plant-beneficial properties such as phytohormone synthesis, nutrient mobilization capacity, and stress-associated enzymatic activities. Inoculation with these strains significantly enhanced plant height, biomass, relative water content, and chlorophyll index under 100 mM NaCl stress in greenhouse conditions. Field trials in saline soils further confirmed improved survival, flower yield, and physiological traits in treated plants. Biochemical analyses revealed increased proline accumulation, enhanced antioxidant enzyme activities (SOD, POD, CAT), and reduced membrane damage, highlighting the stress mitigation effects of these endophytes. Multivariate analysis confirmed strong correlations between microbial traits and plant physiological performance. These results demonstrate the potential of CR-4 and CR-7 as effective bioinoculants for the sustainable cultivation of C. roseus and possibly other crops in salt-affected areas.
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
The combined application of microbial inoculation and seedling transplanting is 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
Salinity is a major constraint to watermelon seedling establishment because it reduces growth, disrupts ion balance, damages membranes, and impairs physiological and biochemical function. Biostimulants improve plant performance under abiotic stress, but the individual and combined effects of microbial and seaweed-based biostimulants on watermelon syoung plants under salinity remain insufficiently understood. Therefore, this study evaluated the effects of the microbial biostimulant (Spectrum-DS), the seaweed-based biostimulant (Kelpak), and their combined application (Kelpak+DS) on the growth, physiology, biochemistry, and mineral composition of young watermelon plants (Citrullus lanatus cv. Jubilee) under salt stress. The experiment was conducted under controlled environment (growth chambers and greenhouses) in two independent cycles using a completely randomized 4 × 3 factorial design, consisting of four biostimulant treatments (Control, Kelpak, Spectrum-DS, and Kelpak+DS) and three salinity levels (0, 30, and 60mM NaCl). In each cycle, five biological replicates were evaluated for each treatment combination. High salinity at 60mM NaCl significantly reduced total dry weight, stem dry weight, shoot length, shoot dry weight, root dry weight, and leaf number compared with the 0mM control. The combined Kelpak+DS treatment mitigated negative effect of salinity, increasing total dry weight by 23.8%, stem dry weight by 33.8%, shoot length by 33.3%, shoot dry weight by 26.3%, root dry weight by 22.2%, and leaf number by 10.2% relative to untreated control. Leaf area was also improved by Kelpak+DSrespectively. Under 60mM salt stress, Kelpak+DS increased total chlorophyll and carotenoids compared to the 60mM control in addition to improving ion homeostasis by reducing Na concentration, Na/K ratio, while increasing K concentration. PCA and correlation analyses further showed that improved growth under Kelpak+DS was associated with greater pigment retention, lower physiological injury, and better mineral balance under salinity. Overall, the combined application of Spectrum-DS and Kelpak was more effective than the individual treatments in mitigating salinity stress during early watermelon growth. These findings suggest that combined microbial and seaweed-based biostimulant application may be a useful strategy for improving watermelon seedling establishment and young plants under saline conditions.
Awais Ali, Joe Masabni, Genhua Niu· Plant Science· 0 citations