Toxic dinoflagellate can produce saxitoxins (STXs) and cause paralytic shellfish poisoning (PSP), and thus they are monitored for environmental safety management. Microscopic discrimination of dinoflagellates is difficult to distinguish between toxic and non-toxic species due to their similar morphology. Meanwhile, an alternative quantitative PCR (qPCR) assay is sensitive, rapid, and cost-effective for harmful species monitoring. Herein, we developed a novel qPCR assay to detect the STXs biosynthesis gene of and , the leading cause of PSP outbreaks in Asian coasts and worldwide. The newly designed TaqMan probes target the species without any positive signal in other relative dinoflagellates. Deming regression analysis revealed that the copy number of and was 3.6 and 4.1 copies per cell, respectively. During the blooming periods (April 13–14, 2020), only cells were detected through the qPCR assay, ranging from 5.0 × 10 to 2.5 × 10 eq cells L. In addition, qPCR quantified more accurately compared to large subunit (LSU) rRNA targeting qPCR assay that overestimate cell density. Besides, the sensitivity of was higher compared to the microscope when the species were rarely present (5.0 × 10 cells L). These suggest that the qPCR assay can be applied to toxic monitoring in the Korean coast, even in the early stage of bloomings.

中文翻译：

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开发石房蛤毒素生物合成基因 sxtB 靶向 qPCR 测定法，用于定量韩国海岸发生的有毒甲藻链状亚历山大藻（I 组）和太平洋甲藻（IV 组）

有毒甲藻可产生石房蛤毒素（STXs）并引起麻痹性贝毒（PSP），因此对其进行监测以进行环境安全管理。由于甲藻的形态相似，用显微镜区分有毒和无毒物种很难区分。同时，另一种定量 PCR (qPCR) 检测方法对于有害物种监测而言灵敏、快速且经济高效。在此，我们开发了一种新型 qPCR 检测方法来检测 和 的 STXs 生物合成基因，这是亚洲沿海和全球 PSP 爆发的主要原因。新设计的 TaqMan 探针针对该物种，在其他相关甲藻中没有任何阳性信号。 Deming 回归分析显示，每个细胞中 和 的拷贝数分别为 3.6 和 4.1 个拷贝。在开花期（2020年4月13日至14日），通过qPCR检测仅检测到细胞，范围为5.0 × 10至2.5 × 10 eq cells L。此外，与大亚基（LSU）rRNA相比，qPCR定量更准确靶向 qPCR 检测会高估细胞密度。此外，当物种很少（5.0 × 10 cells L）时，与显微镜相比，其灵敏度更高。这些表明 qPCR 检测可以应用于韩国海岸的毒性监测，即使是在开花的早期阶段。