Aug 2026· Journal of Ecological Engineering· Vol 27, pp. 412-420· 0 citations· 19 references
TL;DR
Halotolerant endophytes, particularly P. putida KoPr129, are superior candidates for the development of effective bio-inoculants and provide a promising pathway to restore soil fertility and improve wheat productivity in degraded, saline-alkali landscapes, offering a sustainable alternative to chemical fertilizers.
Abstract
Soil salinization and phosphorus (P) deficiency are critical environmental challenges that severely limit global ag - ricultural productivity, particularly in the arid regions of Uzbekistan. Under saline conditions, P is rapidly immobilized, becoming unavailable for plant uptake, which leads to stunted growth and significant yield losses. This study addresses the urgent need for sustainable bio-remediation by evaluating halotolerant endophytic bacteria as effec - tive bio-fertilizers. Several endophytic bacterial strains isolated from native halophytes were screened for their tolerance to extreme salinity (up to 10% NaCl) and their ability to solubilize insoluble phosphates. The most potent isolates, Pseudomonas putida KoPr129 and Bacillus amyloliquefaciens HAPH2, were biochemically characterized for plant growth-promoting (PGP) traits, including IAA, ammonia, and HCN production. A 6-week greenhouse pot experiment was conducted to validate their efficacy on wheat ( Triticum aestivum L.) under 150 mM NaCl stress and P-deficient conditions. In vitro assays confirmed that P. putida KoPr129 maintained a robust phosphate solu - bilization index (FPI 18.16±0.56 mm) even at 10% NaCl. Greenhouse trials demonstrated that inoculation with these endophytes significantly mitigated the negative impacts of combined stress. Specifically, P. putida KoPr129 increased wheat shoot length by 9% and more than doubled the total phosphorus uptake (over 130% increase) compared to the non-inoculated stressed control. Biochemical profiling revealed high levels of IAA produc - tion in both strains, facilitating enhanced root architecture and nutrient acquisition. Our findings demonstrate that halotolerant endophytes, particularly P. putida KoPr129, are superior candidates for the development of effective bio-inoculants. These results provide a promising pathway to restore soil fertility and improve wheat productivity in degraded, saline-alkali landscapes, offering a sustainable alternative to chemical fertilizers.
Findings indicate that Cupriavidus metallidurans YX16 is a salt-tolerant plant growth-promoting rhizobacterium (PGPR) that effectively alleviates salt-induced damage and promotes maize growth, providing a basis for the development of microbial agents for the amelioration of saline-alkali soils.
Saline-alkaline stress is an increasing threat to agricultural productivity due to climate change and anthropogenic activities. Plant growth-promoting bacteria (PGPB) have emerged as a sustainable approach to enhance crop growth and stress tolerance under adverse environmental conditions. In this study, two halotolerant strains,
Kocuria palustris
Pp13 (Pp13) and
Bacillus aryabhattai
Pp16 (Pp16), isolated from the endosphere of Napier grass, were selected to analyze their stress tolerance mechanisms and evaluate their plant growth-promoting traits under saline-alkaline conditions.
The stress tolerance and plant growth-promoting traits of Pp13 and Pp16 was evaluated under different salinity and pH conditions. The effects of bacterial inoculation on the growth and stress tolerance of foxtail millet (
Setaria italica
L.) were assessed by analyzing plant growth, osmotic and oxidative stress responses, and ion accumulation under saline-alkaline conditions.
Both Pp13 and Pp16 formed biofilms and accumulated proline under stress conditions, while their phosphorus-solubilizing activity was only slightly affected by elevated salinity and pH. Notably, Pp13 maintained IAA-like metabolite production and ACC deaminase activity under stress conditions. Inoculation with either strains significantly improved the growth and stress tolerance of foxtail millet under saline-alkaline conditions. Bacterial inoculation increased proline accumulation, elevated ascorbate peroxidase activity, improved photosynthetic performance, and reduced oxidative damage and sodium accumulation, resulting in greater biomass accumulation.
These findings demonstrate that Pp13 and Pp16 possess multiple stress-adaptive and plant growth-promoting traits that contribute to improved crop performance under saline-alkaline conditions. The results highlight the potential of these strains as bioinoculants for sustainable crop production in saline-alkaline soils and identify
Kocuria
species as a relatively unexplored source of beneficial microorganisms for enhancing plant stress tolerance.
Chih-Ning Ko, T. Lee, Wei-Yi Lin· Frontiers in Plant Science· 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
Drought stress is among the most critical limitations to maize productivity, particularly under rainfed conditions. In this study, we explored the Brazilian Caatinga biome as a source of drought adapted plant growth-promoting bacteria and evaluated their potential to mitigate drought effects in maize (Zea mays L.). A total of 414 thermo-tolerant bacterial strains were isolated from soil, of which 28 Bacillus strains were able to grow under low water activity. These strains exhibited multiple plant growth-promoting traits in vitro, including exopolysaccharide production, biofilm formation, siderophore production, indole-3-acetic acid synthesis, putative nitrogen fixation, and phosphate solubilization. Twelve selected strains significantly improved root morphology, relative chlorophyll content (SPAD units), and biomass accumulation in maize seedlings under osmotic stress induced by polyethylene glycol. Notably, strain 1A11 showed the most consistent effects, promoting root growth and biomass accumulation under both stressed and non-stressed conditions, indicating constitutive growth promotion across environments, whereas other strains showed stronger responses under stress. This stability across environments strengthens its agronomic value, particularly in regions characterized by high rainfall variability. Genome sequencing of five elite strains (1A11, 5D5, 6E9, 1H10, and 2E7) identified conserved gene clusters associated with exopolysaccharide production, indole-3-acetic acid synthesis, phosphate metabolism, iron acquisition (siderophore synthesis), synthesis of volatile compounds, motility, chemotaxis, and general responses to osmotic and oxidative stress. Multi-location field trials conducted across five locations in Brazil, under rainfed conditions, indicate that strains 1A11 (Bacillus subtilis), 5D5, and 6E9 (Bacillus velezensis) consistently increased grain yield compared to the non-inoculated control and performed similarly to or better than a commercial inoculant. Mean productivity gains with the strain 1A11 reached up to 39% relative to the non-inoculated treatment across environments. These results indicate that Bacillus strains isolated from semi-arid soils were able to convert multifunctional potential into measurable agronomic gains under field conditions, demonstrating their potential as bioinoculants to enhance maize resilience under water-limited agricultural systems.
U. G. Lana, S. D. de Sousa, B. T. V. Godinho et al.· Frontiers in Plant Science· 0 citations
This study introduces L. aquatilis strain MC3 as an emerging candidate for bioinoculant development and one of the first reports for identification of L. aquatilis as multifunctional PGPR from Himalayan ecosystems.
S. Devi, Riya Chandel, D. Thakur et al.· Frontiers in Systems Biology· 0 citations
Phosphorus (P) is an indispensable nutrient and a limiting factor affecting plant growth and development. To address P deficiency in plants, synthetic phosphate fertilisers are often used despite concerns over their ecological impacts. The use of microbial and non-microbial biostimulants is a plausible, eco-friendly alternative to enhance plant P acquisition. In this study, the in vitro quantitative P-solubilising potential of four endophytic species (
Aspergillus niger
,
Fusarium oxysporum
,
Serratia marcescens
, and
Paenibacillus polymyxa
) was evaluated. The P-acquisition-enhancing potential of endophyte-inoculated cucumber seedlings grown on P-starved hydroponic medium and supplemented with commercial seaweed biostimulant (Kelpak
®
) was also investigated. The four endophytic strains demonstrated the ability to solubilise the phosphates from substrates containing aluminium, calcium and iron.
Aspergillus niger
had the highest P-solubilising capacity from the three substrates. Under P-starvation, the four endophytic species had the capacity to colonise the internal tissues of the seedlings, and P-limitation led to a reduction in the root biomass, photosynthetic pigment concentration and root-to-shoot ratio in cucumber seedlings. However, endophytic inoculation and Kelpak
®
supplementation of the growth medium enhanced leaf area and foliar P content in cucumber seedlings. Endophytic inoculations with or without Kelpak
®
supplementation decreased phosphatase activity in root exudates of the seedlings. The results revealed that the four endophytic strains have the capacity to solubilise P and colonise cucumber root tissues. The endophytic species, in conjunction with the seaweed extract, enhanced the morpho-physio-biochemical adaptive responses of cucumber seedlings to P-limitation. Thus, inoculating cucumber seedlings with beneficial microbes and adding Kelpak
®
to the growth medium is a promising, sustainable strategy to enhance cucumber production under P limitation.
A. Ogbe, A. Muddathir, M. Kulkarni et al.· Plant growth regulation (Pri...· 0 citations
