# Cadmium Stress Disrupts Auxin Signaling and Growth in Ilex verticillata: Insights from Physiological and Transcriptomic Analyses

## TL;DR

This study explores how the ornamental plant Ilex verticillata responds to cadmium stress, revealing that auxin signaling plays a key role in its tolerance to heavy metal pollution.

## Contribution

The study identifies a regulatory module involving IvIAA genes and the transcription factor IvMYB77 in Ilex verticillata's response to cadmium stress.

## Key findings

- Cadmium stress inhibits stem growth and reduces photosynthetic capacity in Ilex verticillata.
- Transcriptomic analysis shows significant enrichment of auxin signaling pathways under cadmium stress.
- Six nucleus-localized IvIAA genes interact with the transcription factor IvMYB77 in Cd stress responses.

## Abstract

Cadmium (Cd) pollution poses significant threats to ecosystems and human health, with agricultural soils in China particularly affected. Ilex verticillata, a popular ornamental plant, has not been extensively studied for its response to Cd stress. This study investigated the physiological and molecular mechanisms underlying Cd stress tolerance in I. verticillata, focusing on auxin signaling pathways. Under Cd stress (500 mmol/kg soil), I. verticillata exhibited inhibited stem growth, reduced photosynthetic capacity, and elevated oxidative stress markers such as malondialdehyde, H2O2, ·O2−, and antioxidant enzyme activities. Transcriptomic analysis revealed 3750 differentially expressed genes (DEGs) with significant enrichment in auxin signaling pathways. Six nucleus-localized IvIAA genes were identified and shown to interact with the transcription factor IvMYB77, suggesting a regulatory module in Cd stress responses. These findings highlight the role of auxin signaling in mediating Cd stress tolerance and provide insights into the molecular adaptation of I. verticillata to heavy metal pollution.