Exogenous γ-polyglutamic acid alleviates cadmium stress in rice through redox regulation and modulation of cadmium
Rong Huang1, Qiang Qiang1, Zhichao Wang1
1School of Life Sciences, Hubei University, Wuhan, China.
Background:
Cadmium (Cd) contamination severely threatens crop production and irreversibly damages plant growth, yield, and quality. The purpose of the present study was to investigate the effect of γ-polyglutamic acid (γ-PGA) on Cd tolerance in rice during the whole growth period.
Methods:
The experiment consisted of four treatments: a control group with neither γ-PGA nor Cd; a group treated with γ-PGA alone; a group treated with Cd alone; and a group treated with both γ-PGA and Cd.
Results:
Results showed that γ-PGA significantly alleviated Cd stress by promoting rice growth and immobilizing bioavailable Cd in soil. Physiological analysis showed that chlorophyll and shoot proline peaked at the tillering stage, while root proline peaked at the heading stage. Malondialdehyde (MDA) and H2O2 increased with growth, with higher MDA in roots. Antioxidant enzymes showed distinct patterns. Superoxide dismutase and root catalase peaked at the tillering stage, shoot peroxidase at the heading stage. Under Cd stress, chlorophyll synthesis was markedly inhibited, oxidative damage was induced, and the antioxidant defense system was activated. γ-PGA alone had no significant effect, whereas Cd + γ-PGA co-treatment effectively mitigated Cd toxicity by increasing chlorophyll, antioxidant enzyme activities, and proline accumulation, as well as reducing oxidative damage, with the most pronounced effects at the tillering and maturity stages. Principal component analysis further indicated that the alleviative role of γ-PGA was growth stage-specific.
Conclusion:
Research findings, therefore, suggest that γ-PGA can ameliorate Cd toxicity in rice, resulting in improved plant growth under metal stress. © 2026 Society of Chemical Industry.
