The algal cell wall is an important cellular component that functions in defense, nutrient utilization, signaling, adhesion, and cell–cell recognition—processes important in the cnidarian–dinoflagellate symbiosis. The cell wall of symbiodiniacean dinoflagellates is not well characterized. Here, we present a method to isolate cell walls of Symbiodiniaceae and prepare cell-wall-enriched samples for proteomic analysis. Label-free liquid chromatography–electrospray ionization tandem mass spectrometry was used to explore the surface proteome of two Symbiodiniaceae species from the Great Barrier Reef: Breviolum minutum and Cladocopium goreaui. Transporters, hydrolases, translocases, and proteins involved in cell-adhesion and protein–protein interactions were identified, but the majority of cell wall proteins had no homologues in public databases. We propose roles for some of these proteins in the cnidarian–dinoflagellate symbiosis. This work provides the first proteomics investigation of cell wall proteins in the Symbiodiniaceae and represents a basis for future explorations of the roles of cell wall proteins in Symbiodiniaceae and other dinoflagellates.

中文翻译：

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刺胞光共生菌 Breviolum minutum 和 Cladocopium goreaui 的细胞壁蛋白质组学分析

藻类细胞壁是一种重要的细胞成分，在防御、营养利用、信号传导、粘附和细胞-细胞识别中发挥作用——这些过程在刺胞动物-甲藻共生中很重要。共生生物甲藻的细胞壁没有很好的表征。在这里，我们提出了一种分离共生菌科细胞壁并制备富含细胞壁的样品进行蛋白质组学分析的方法。无标记液相色谱-电喷雾串联质谱法用于探索大堡礁的两种共生菌科物种的表面蛋白质组：Breviolum minutum和Cladocopium goreaui. 确定了参与细胞粘附和蛋白质-蛋白质相互作用的转运蛋白、水解酶、转位酶和蛋白质，但大多数细胞壁蛋白在公共数据库中没有同源物。我们提出了其中一些蛋白质在刺胞动物-甲藻共生中的作用。这项工作提供了对共生藻科细胞壁蛋白的首次蛋白质组学研究，并为未来探索细胞壁蛋白在共生藻科和其他甲藻中的作用奠定了基础。