Overexpression of ZmSKD1 improves cadmium tolerance through the vesicle trafficking pathway in tobacco.

Cadmium (Cd) is a major soil pollutant that threatens plant growth and human health. The plant ATPase associated with various cellular activities (AAA) SKD1 utilizes ATP hydrolysis energy to mediate cellular responses to environmental stress. However, the role and regulatory mechanisms of SKD1 in plant responses to Cd stress are not well understood. This study has demonstrated that the maize SKD1 gene (ZmSKD1) enhanced tobacco's tolerance to Cd stress. Overexpression of ZmSKD1 in tobacco reduced Cd accumulation and improved Cd tolerance. Moreover, ZmSKD1 overexpression enhanced the antioxidant capacity of tobacco, maintaining reactive oxygen species homeostasis and mitigating oxidative damage under Cd stress. The transcription factor AGL8 directly activated ZmSKD1 transcription, which in turn boosted ATPase activity in tobacco. This activation enhanced vesicle trafficking in root cells and accelerated Cd excretion in transgenic tobacco plants. Concurrently, the AGL8-ZmSKD1 module inhibited the expression of several Cd transport-related genes, thereby reducing Cd uptake by tobacco roots. These findings identified the AGL8-ZmSKD1 module as a crucial player in managing Cd stress through the vesicle trafficking pathway, offering valuable insights into strategies for developing crops with reduced Cd accumulation to ensure global food security and human health.