# Crosstalk between glutathione and melatonin in chromium detoxification in sweet potato revealed by high-throughput sequencing and physio-biochemical profiling

## TL;DR

The study explores how glutathione and melatonin help sweet potato plants tolerate chromium stress by analyzing gene expression and biochemical responses.

## Contribution

The paper reveals novel molecular mechanisms of chromium detoxification in sweet potato through integrated transcriptomic and biochemical profiling.

## Key findings

- Transcriptome analysis identified 7,734 differentially expressed genes under chromium stress and mitigator treatments.
- Glutathione-specific protection was linked to enhanced redox and metabolic control via Cluster C4 gene expression.
- Key hub genes like GA20OX1, HEMA1, and TIP2-1 were identified as central to chromium stress mitigation.

## Abstract

Chromium (Cr) contamination severely inhibits plant productivity, primarily by disrupting photosynthetic performance, growth, and inducing oxidative stress. This study investigated the comparative molecular mechanisms by which exogenous glutathione (GSH) and melatonin (MT) confer tolerance to Cr stress in sweet potato using an integrated transcriptomic approach. Transcriptome analysis identified 7,734 differentially expressed genes (DEGs) across Cr stress and mitigator treatments. The GO and KEGG pathway enrichment analyses showed that DEGs were mainly enriched in GO terms, such as photosynthesis, carbon fixation, and cell-wall organization, as well as pathways including MAPK signaling, glutathione metabolism, plant hormone signal transduction, and membrane/vesicle transport. These DEGs were subjected to cluster analysis, and four major expression clusters (C1-C4) were identified, with DEGs ranging from 1,234 to 3,285. GSH-specific protection was associated with Cluster C4, enhancing genes involved in ROS defense, H2O2 response, pyruvate metabolism, and ER protein processing, indicating improved redox and metabolic control Network analysis identified 30 potential key hub genes, including the growth regulator GA20OX1, the chlorophyll synthesis enzyme HEMA1, and the vacuolar transport aquaporin TIP2-1. These results suggest that GSH induces a stronger transcriptional response by effectively mitigating Cr-induced damage and strengthening a redox-centered defensive metabolic network. This identifies actionable molecular targets for crop improvement through breeding and genetic engineering.