Li Jiashun, Wang Jingtian, Wang Xiaoyu, Zhang Kaidian, Lin Senjie
State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou 570228, China.
State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China.
Microorganisms. 2025 Aug 10;13(8):1867. doi: 10.3390/microorganisms13081867.
SPX domain-containing proteins (SPXc) are crucial for regulating phosphorus (P) homeostasis in plants. Recently, the SPX gene was identified in the diatom model and shown to serve as a negative regulator of P acquisition. Whether occurs in dinoflagellates is unclear. Here, we report the presence and potential functions of genes encoding SPXc in dinoflagellates (). Four classes of SPXc were identified in dinoflagellates, including the three known classes-the stand-alone SPX, SPX-EXS, and SPX-VTC-and SPX-other, with SPX and SPX-EXS being dominant. Using the database, we investigated the taxonomic and geographic distributions of and found variations in expression among size classes of dinoflagellates. The harmful algal bloom-causative species possesses all four classes of SPXc proteins, showing a fluctuating expression pattern under different nutrient conditions and during different phases of the cell cycle and algal bloom. In addition, the genes in Symbiodiniaceae respond not only to P stress but also to thermal variations. These results are consistent with a role of in maintaining P homeostasis in dinoflagellates and suggest the importance of SPX-related genes in enabling dinoflagellates to sustain population growth in nutrient-variable oceans, warranting further research.
含SPX结构域的蛋白质（SPXc）对植物中磷（P）稳态的调节至关重要。最近，在硅藻模型中鉴定出了SPX基因，并表明其作为磷获取的负调节因子。目前尚不清楚在甲藻中是否存在该基因。在此，我们报告了甲藻中编码SPXc的基因的存在及其潜在功能。在甲藻中鉴定出了四类SPXc，包括三种已知类型——独立的SPX、SPX-EXS和SPX-VTC——以及SPX-other，其中SPX和SPX-EXS占主导地位。利用数据库，我们研究了甲藻的分类和地理分布，并发现了不同大小类别的甲藻中SPXc表达的差异。有害藻华致病物种拥有所有四类SPXc蛋白，在不同营养条件下以及细胞周期和藻华的不同阶段呈现出波动的表达模式。此外，共生藻科中的SPXc基因不仅对磷胁迫有反应，对温度变化也有反应。这些结果与SPXc在维持甲藻磷稳态中的作用一致，并表明SPX相关基因在使甲藻能够在营养可变的海洋中维持种群增长方面的重要性，值得进一步研究。
