# Synergistic alleviation effects of salt-tolerant plant growth-promoting rhizobacteria and hydrogen-rich water on salt stress in.
> 耐塩性植物成長促進根圏細菌と水素水の併用による塩ストレス軽減効果とその分子メカニズム


## Abstract

Soil salinization poses a major constraint on agricultural productivity. This study examined the combined effects of a salt-tolerant plant growth-promoting rhizobacterium (PGPR) strain L71 and hydrogen-rich water (HRW) on plants under NaCl stress using a factorial pot experiment at three salinity levels (0, 250, and 500 mM NaCl). Under severe salinity, the combined PGPR-HRW treatment increased shoot fresh weight by 148% and root length by 54.60% relative to untreated controls. Antioxidant enzyme activities (SOD, POD, CAT) were elevated, while oxidative stress markers MDA and H₂O₂ were reduced. Transcriptome profiling revealed enrichment in plant hormone signaling, MAPK signaling, and plant-pathogen interaction pathways. Negative regulators including CaM/CML, CDPK, WRKY25/33, and JAZ were down-regulated, whereas the positive regulator A-ARR was up-regulated, collectively supporting stomatal function, delayed senescence, and improved ROS homeostasis. These findings indicate that coordinated physiological and transcriptional responses underlie the synergistic salt-tolerance enhancement achieved by combining microbial inoculants with HRW.

### Mechanism

Combined PGPR and HRW application elevates SOD, POD, and CAT activities while reducing MDA and H₂O₂ accumulation. Through MAPK and hormone signaling pathways, negative regulators (CaM/CML, CDPK, WRKY25/33, JAZ) are suppressed and the positive regulator A-ARR is induced, sustaining ROS balance, stomatal function, and delaying senescence.

## Bibliographic

- **Authors**: Chu S, Xu T, Feng YQ, Ma X, Shu RC, Wang R, et al.
- **Journal**: Front Plant Sci
- **Year**: 2025
- **PMID**: [41234312](https://pubmed.ncbi.nlm.nih.gov/41234312/)
- **DOI**: [10.3389/fpls.2025.1702577](https://doi.org/10.3389/fpls.2025.1702577)
- **PMC**: [PMC12605088](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12605088/)
- **Study type**: other
- **Delivery route**: hydrogen-rich water
- **Effect reported**: positive

## Delivery context

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 41234312. https://h2-papers.org/en/papers/41234312
> **Source**: PubMed PMID [41234312](https://pubmed.ncbi.nlm.nih.gov/41234312/)