Microalgal glutaredoxin 1 interacts with transcription factor bZIP to resist cadmium stress via lipid metabolism...

Triacylglycerol (TAG), a universal energy reserve and biodiesel feedstock, accumulates under stress in microalgae. However, the regulatory mechanisms linking stress signals to TAG synthesis remain unclear. In this study, we identified ApGRX1724, a novel glutaredoxin 1 family member found in Auxenochlorella protothecoides, that could translocate to the nucleus and interact with the transcription factor ApbZIP4896, which regulating TAG synthesis by interacting with the synthetase ApPAP6812. Additionally, ApbZIP4896 modulated the levels of reactive oxygen species (ROS) and influenced TAG polyunsaturation. This shifted the carbon metabolism of microalgae from lipid production to growth by interacting with ApMyb_rel4269 and ApbZIP0838, ultimately enhancing the resistance of microalgae to cadmium (Cd). This study revealed a novel signaling pathway involving ApGRX1724 and ApbZIP4896 that positively mediates resistance to Cd-induced ROS stress and promotes TAG accumulation, providing valuable insights into how microalgae resist Cd toxicity.