Ectopic Expression of AetPGL from Aegilops tauschii Enhances Cadmium Tolerance and Accumulation Capacity in Arabidopsis thaliana

Cadmium (Cd) is a toxic heavy metal that accumulates in plants, negatively affecting their physiological processes, growth, and development, and poses a threat to human health through the food chain. 6-phosphogluconolactonase (PGL) is a key enzyme in the Oxidative Pentose Phosphate Pathway(OPPP) in plant cells, essential for cellular metabolism. The OPPP pathway provides energy and raw materials for organisms and is involved in antioxidant reactions, lipid metabolism, and DNA synthesis. This study describes the Cd responsive gene <i>AetPGL</i> from <i>Aegilops tauschii.</i> Overexpression of <i>AetPGL</i> under Cd stress increased main root length and germination rate in <i>Arabidopsis</i>. Transgenic lines showed higher antioxidant enzyme activities and lower malondialdehyde (MDA) content compared to the wild type. The transgenic <i>Arabidopsis</i> accumulated more Cd in the aboveground part but not in the underground part. Expression levels of <i>AtHMA3</i>, <i>AtNRAMP5</i>, and <i>AtZIP1</i> in the roots of transgenic plants increased under Cd stress, suggesting AetPGL may enhance Cd transport from root to shoot. Transcriptome analysis revealed enrichment of differentially expressed genes (DEGs) in the plant hormone signal transduction pathway in <i>AetPGL</i>-overexpressing plants. Brassinosteroids (BR), Gibbenellin acid (GA), and Jasmonic acid (JA) contents significantly increased after Cd treatment. These results indicate that <i>AetPGL</i> may enhance <i>Arabidopsis</i>' tolerance to Cd by modulating plant hormone content. In conclusion, <i>AetPGL</i> plays a critical role in improving cadmium tolerance and accumulation and mitigating oxidative stress by regulating plant hormones, providing insights into the molecular mechanisms of plant Cd tolerance.