# Prohydrojasmonate–silicon synergy enhances cadmium detoxification and stress tolerance in rice, Oryza sativa L

## TL;DR

Applying prohydrojasmonate and silicon together helps rice plants handle cadmium pollution better by reducing cadmium uptake and improving stress tolerance.

## Contribution

The study reveals a synergistic effect of prohydrojasmonate and silicon in enhancing cadmium detoxification and stress tolerance in rice.

## Key findings

- PDJ-Si co-treatment significantly reduced cadmium translocation to aerial tissues and improved photosynthetic efficiency.
- Combined PDJ and Si application enhanced membrane stability, osmotic balance, and nutrient restoration more than individual treatments.
- The treatment activated detoxification genes and hormonal pathways, improving plant resilience to cadmium stress.

## Abstract

Cadmium (Cd) contamination severely threaten rice productivity and food security, yet effective and sustainable detoxification strategies remain limited. This study investigates whether combined application of prohydrojasmonate (PDJ) and silicon (Si) can synergistically enhance Cd detoxification in rice. Rice seedlings exposed to Cd stress were treated with PDJ, Si or their combination and evaluated through integrated physiological, biochemical and molecular analyses including metal accumulation, photosynthetic performance, oxidative status, hormonal regulation and gene expression. Compared to individual treatments, PDJ-Si co-treatment significantly reduced Cd translocation to aerial tissues, with maximum root retention restored essential leaf elements (Fe, K, Mn) and enhanced photosynthetic efficiency. While PDJ and Si individually enhanced membrane stability, reduced lipid peroxidation and improved osmotic balance their combined application produced the most pronounced effects. Phytohormone profiling revealed coordinated activation of salicylic acid (SA) and jasmonic acid (JA) pathways with balanced abscisic acid (ABA) modulation. Furthermore, both individual and combine application caused differential expression of genes related to detoxification (OsABCC1, OsGSTU5, OsPCS1), metal transporters (OsHMA2, OsLCT1) and hormone biosynthesis (OsABA2, OsEDS1, OsAOS2). Collectively, these findings demonstrate that PDJ and Si application enhance Cd detoxification and stress tolerance in rice providing a promising approach for sustainable rice cultivation in Cd-contaminated soils.

Foliar application of PDJ and Si synergistically mitigates Cd toxicity in rice by reducing Cd uptake and translocation while regulating metal transport genes, detoxification pathways and hormonal responses. The combined treatment enhances photosynthesis, restores nutrient balance, improves membrane integrity and osmotic balance, ultimately improving plant stress tolerance under Cd stress.Diagram of the effects of foliar PDJ and Si application on plants experiencing Cd²⁺ stress. The application leads to reduced cadmium in roots and shoots, improved photosynthesis, restored essential nutrients, enhanced membrane integrity, better osmotic balance, and improved stress tolerance. The diagram shows hormonal and transcriptional regulation in the cell membrane, regulation of metal transport and detoxification genes, and balanced ABA modulation, leading to less cadmium translocation.

Foliar application of PDJ and Si synergistically mitigates Cd toxicity in rice by reducing Cd uptake and translocation while regulating metal transport genes, detoxification pathways and hormonal responses. The combined treatment enhances photosynthesis, restores nutrient balance, improves membrane integrity and osmotic balance, ultimately improving plant stress tolerance under Cd stress.