Abstract

Simple SummarySince 2007, the periodic excessive proliferation ofUlva proliferain the Yellow Sea of China has had a significant impact on the ecological environment. Their astonishing abiotic stress tolerance is regarded as one of the reasons why they can thrive in harsh environments. In this study, we characterized an MYB-related transcription factor fromU. prolifera, namely UpMYB-PHL, which has been proven to be involved in the salt stress response of algae. We also reveal how UpMYB-PHL-coordinates phosphorus transporter and energy metabolism in response to salt stress inU. prolifera.The results of this study provide a new perspective for understanding the salt stress tolerance ofU. prolifera.Ulva proliferais the main causative species of marine green tides and exhibits extreme tolerance to intertidal abiotic stress. However, the underlying molecular mechanisms remain largely unclear. In this study, we cloned and characterized an MYB-related transcription factor, UpMYB-PHL, fromU. prolifera. Expression analysis showed thatUpMYB-PHLis rapidly and significantly induced by high-salt stress. Furthermore, heterologous overexpression ofUpMYB-PHLin the model microalgaChlamydomonas reinhardtiisignificantly improved its salt tolerance and biomass. By yeast one-hybrid and dual-luciferase assays, we demonstrated that UpMYB-PHL directly binds to and activates the promoter of the phosphate transporter geneUpPHT1, which is a typical target gene of phosphate response (PHR) transcription factor and participates in salt stress responses of plants. Interestingly, yeast two-hybrid assays revealed that UpMYB-PHL physically interacts with UpGAPDH, a core enzyme in energy metabolism. Taken together, our findings reveal a novel regulatory network in which UpMYB-PHL coordinates phosphorus transporter and energy metabolism in response to salt stress inU. prolifera. This study provides a vital molecular explanation for the rapid adaptation and massive growth ofU. proliferaunder severe int