Morpho-physiological and transcriptomic analyses reveal adaptive responses of Neopyropia yezoensis to long-term high temperature

• First report on the adaptive responses of Neopyropia yezoensis to long-term high temperature. • This study is the first to report the phenomenon that thallus color change of Neopyropia yezoensis under long-term high temperature. • Reveal a novel role of phycoerythrin in high temperature tolerance in Neopyropia yezoensis . • Propose a model of possible mechanisms of Neopyropia yezoensis adapting to long-term high temperature. High temperature has a significant impact on growth and yield of Neopyropia yezoensis , and its effects are expected to increase in the near future due to global warming. Thus, understanding the high-temperature response of N. yezoensis and enhancing its ability to adapt to high temperature have become of critical importance to aquaculture development. In this study, we investigated the changes in morphology, physiology and transcriptome of a high-temperature tolerant strain of N. yezoensis under high temperature to explore its response mechanism to high temperature. Notable changes have been observed in thallus color, relative growth rates, pigment composition, chlorophyll fluorescence, ROS levels and gene expression. Our results suggested that thallus color change was one of the most important adaptive responses of N. yezoensis to long-term high temperature, and was reported for the first time in our present study. Moreover, accumulation of phycoerythrin could confer high temperature tolerance to N. yezoensis . Finally, combining our data with previous reports, we proposed a model of possible mechanisms of N. yezoensis adapting to long-term high temperature. Our findings provide new insights into the adaptative mechanisms of N. yezoensis to high temperature environments, which could be helpful for improving the high-temperature tolerance of N. yezoensis and other economic algae in the aquaculture industry.