# Yucasin Alleviates Aluminum Toxicity Associated with Regulating Reactive Oxygen Species Homeostasis in Tomato Seedlings

## TL;DR

Yucasin helps tomato seedlings resist aluminum toxicity by reducing harmful oxygen molecules and boosting antioxidant activity.

## Contribution

This study reveals yucasin's novel role in mitigating aluminum toxicity through ROS regulation and antioxidant enzyme activation.

## Key findings

- Yucasin reduces aluminum accumulation and ROS levels in tomato roots.
- Yucasin enhances antioxidant enzyme activities like SOD, CAT, and POD.
- Yucasin promotes root growth and viability under aluminum stress.

## Abstract

The phytotoxicity of aluminum (Al) to plants is well known. Auxin accumulation and reactive oxygen species (ROS) burst induced by Al toxicity are the key factors in root growth inhibition. Yucasin, an auxin synthesis inhibitor, effectively ameliorates Al phytotoxicity in tomato seedlings. However, the physiological mechanisms by which yucasin alleviates Al phytotoxicity in tomatoes remain elusive. Here, we examined the regulatory mechanisms of yucasin involved in tomato seedling growth under Al conditions through phenotypic, plant physiology analysis, and cellular experiments. Exogenous indole-3-acetic acid (IAA) application increased Al accumulation in tomato seedling roots, while yucasin decreased Al accumulation. Yucasin application reduced Al-induced ROS accumulation, lipid peroxidation, and cell death, enhanced root viability, and promoted tomato seedling root growth. Further, yucasin enhanced the antioxidant enzyme activities of superoxide dismutase, catalase, and peroxidase in plants under Al conditions. The results suggest that yucasin improves the scavenging capacity of ROS by maintaining the activities of antioxidative enzymes. This study elucidates the physiological mechanism by which yucasin alleviates Al phytotoxicity, highlighting its potential to enhance plant tolerance under acidic Al conditions.