Dimethylsulfoniopropionate (DMSP) is an important organic carbon and sulfur source in the surface ocean that fuels microbial activity and significantly impacts Earth's climate. After three decades of research, the cellular role(s) of DMSP and environmental drivers of production remain enigmatic. Recent work suggests that cellular DMSP concentrations, and changes in these concentrations in response to environmental stressors, define two major groups of DMSP producers: high DMSP producers that contain ≥ 50 mM intracellular DMSP and low DMSP producers that contain < 50 mM. Here we show that two recently described DMSP synthesis genes (DSYB and TpMT2) may differentiate these two DMSP phenotypes. A survey of prokaryotic and eukaryotic isolates found a significant correlation between the presence of DSYB and TpMT2 genes and previous measurements of high and low DMSP concentrations, respectively. Phylogenetic analysis demonstrated that DSYB and TpMT2 form two distinct clades. DSYB and TpMT2 were also found to be globally abundant in in situ surface communities, and their taxonomic annotations were similar to those observed for isolates. The strong correlation of the DSYB and TpMT2 synthesis genes with high and low producer phenotypes establishes a foundation for direct quantification of DMSP producers, enabling significantly improved predictions of DMSP in situ.

中文翻译：

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DMSP 合成基因区分两种类型的 DMSP 生产者表型

二甲基磺基丙酸盐 (DMSP) 是表层海洋中重要的有机碳和硫源，可促进微生物活动并显着影响地球气候。经过三年的研究，DMSP 的细胞作用和生产的环境驱动因素仍然是个谜。最近的工作表明，细胞 DMSP 浓度以及这些浓度因环境压力而发生的变化，定义了两个主要的 DMSP 生产者群体：含有 ≥ 50 mM 细胞内 DMSP 的高 DMSP 生产者和含有 < 50 mM 的低 DMSP 生产者。在这里，我们展示了两个最近描述的 DMSP 合成基因（DSYB和TpMT2) 可以区分这两种 DMSP 表型。一项对原核和真核分离株的调查发现，DSYB和TpMT2基因的存在与之前分别测量的高和低 DMSP 浓度之间存在显着相关性。系统发育分析表明DSYB和TpMT2形成两个不同的进化枝。还发现DSYB和TpMT2在原位表面群落中全球丰富，它们的分类注释与观察到的分离株相似。DSYB和TpMT2的强相关性具有高和低生产者表型的合成基因为直接量化 DMSP 生产者奠定了基础，从而显着改善了 DMSP的原位预测。