Nitric oxide alleviates selenium toxicity in rice by regulating antioxidation, selenium uptake, speciation and gene...

Area of Science:

• Plant Physiology
• Environmental Toxicology
• Agricultural Science

Background:

• Excess selenium (Se) induces toxicity in plants, impacting growth and development.
• Nitric oxide (NO) is known to confer tolerance to various abiotic stresses in plants.

Purpose of the Study:

• To investigate the protective mechanisms of exogenous nitric oxide (NO) against high selenium (Se) toxicity in rice.
• To understand how NO influences Se uptake, speciation, and the physiological responses in rice under Se stress.

Main Methods:

• Rice seedlings were subjected to high Se (25 μM) stress with or without exogenous NO (sodium nitroprusside).
• Evaluated growth parameters, Se content and speciation, photosynthetic efficiency, antioxidant enzyme activities, and gene expression (OsPT2, OsSAMS1, OsCS, OsSBP1) via qRT-PCR.

Main Results:

• Exogenous NO alleviated Se-induced damage to root morphology, growth, and photosynthesis.
• NO treatment significantly reduced MDA, H2O2, and proline levels, indicating reduced oxidative stress.
• Application of NO decreased root Se content by 10% and completely eliminated Se(VI) in roots and shoots, altering inorganic Se speciation.
• Gene expression analysis revealed that NO down-regulated OsPT2, OsSAMS1, and OsCS, suggesting a role in Se metabolism regulation.

Conclusions:

• Exogenous NO effectively mitigates high Se toxicity in rice by improving physiological functions and reducing Se accumulation.
• NO influences Se speciation and the expression of key Se transport and metabolism genes, offering a strategy for safe Se-enriched rice production.