Extreme climate events, such as marine heatwaves (MHWs), are expected to occur more frequently and intensely in the future, resulting in a substantial impact on marine life. As the most important marine primary producer, the way that diatoms respond to MHWs may have a significant effect on global primary production and biogeochemical cycles. To address this, we investigated the underlying mechanisms of Pseudo-nitzschia multiseries to respond to simulated heatwaves conditions.