RUB-Associated Regulation of Aluminum Sensitivity Reveals a New Layer of Aluminum Stress Signaling in Arabidopsis.

Aluminum (Al) toxicity in acidic soils is a major constraint on global crop production, inhibiting root growth, and disrupting redox homeostasis. In this study, we identify the RING/U-box E3 ubiquitin ligase (RUB) as a regulator associated with Al responses in Arabidopsis thaliana through genome-wide association analysis (GWAS) across eight root architectural traits. Functional characterization of rub T-DNA mutants and RUB overexpression (OE) lines demonstrated RUB functions as a positive regulator of Al-induced inhibition of root growth and oxidative stress, with rub mutants exhibiting enhanced root growth, decreased Al accumulation, reduced reactive oxygen species (ROS) levels and DNA damage while OE lines showed impaired root architecture growth, increased Al retention in root tips, elevated oxidative stress and DNA damage. Transcriptomic analysis of transgenic lines further revealed differential expression of genes associated with four major biological processes: MAPK signaling, hormonal signaling, root hair and lateral root development, and the oxidative stress response, suggesting coordinated stress response mechanisms. Overall, this study provides new insights into plant adaptation to Al stress and establishes a foundation for future studies investigating the molecular role and downstream targets of RUB.