# Transcriptome analysis reveals insight into molecular hydrogen-induced cadmium tolerance in alfalfa: the prominent role of sulfur and (homo)glutathione metabolism.
> アルファルファにおける水素誘導カドミウム耐性の転写解析：硫黄および（ホモ）グルタチオン代謝の重要な役割


## Abstract

This study examined how hydrogen-rich water (HRW) confers cadmium (Cd) tolerance in alfalfa seedling roots using RNA-Seq transcriptome profiling. Under Cd and/or HRW conditions, 1,968 differentially expressed genes were identified, clustering into categories including glutathione (GSH) metabolism, oxidative stress response, and ABC transporter activity. RT-qPCR validation confirmed that HRW upregulated genes associated with sulfur and (homo)glutathione metabolism under Cd exposure. Pharmacological inhibition of glutathione synthesis and experiments with Arabidopsis thaliana cad2-1 mutants demonstrated the central contribution of glutathione to HRW-mediated Cd tolerance. Elevated (homo)glutathione and (homo)phytochelatin levels were consistent with reduced oxidative stress markers. Additionally, HRW appeared to lower bioavailable Cd in roots through ABC transporter-dependent secretion. Collectively, the findings indicate that molecular hydrogen modulates sulfur and glutathione metabolic gene networks, enhancing antioxidant capacity and Cd chelation as dual mechanisms underlying Cd tolerance.

### Mechanism

Molecular hydrogen upregulates sulfur and (homo)glutathione metabolism genes in alfalfa roots, boosting antioxidant capacity and phytochelatin-mediated Cd chelation, while also promoting ABC transporter-dependent Cd secretion to reduce intracellular cadmium availability.

## Bibliographic

- **Authors**: Cui W, Yao P, Pan J, Dai C, Cao H, Chen Z, et al.
- **Journal**: BMC Plant Biol
- **Year**: 2020 (2020-02-04)
- **PMID**: [32019510](https://pubmed.ncbi.nlm.nih.gov/32019510/)
- **DOI**: [10.1186/s12870-020-2272-2](https://doi.org/10.1186/s12870-020-2272-2)
- **PMC**: [PMC7001311](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7001311/)
- **Study type**: in vitro study
- **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 32019510. https://h2-papers.org/en/papers/32019510
> **Source**: PubMed PMID [32019510](https://pubmed.ncbi.nlm.nih.gov/32019510/)