Poterioochromonas malhamensis is a flagellate grazer that readily contaminates Chlorella cultures and can have a devastating impact on them, especially in large-scale culture. Here, we developed a quantitative real-time polymerase chain reaction (qPCR) method to detect and quantify P. malhamensis from high-density Chlorella cultures. A set of primers specific to the mitochondrial cytochrome oxidase subunit I gene (COI) of P. malhamensis was screened and characterized comprehensively for specificity, sensitivity and applicability to the field samples. The results showed that the primers were sufficiently specific to distinguish P. malhamensis from a wide variety of micro-eukaryotes which often coexist with P. malhamensis in microalgal cultures, and could detect a very low concentration of P. malhamensis from high concentrations of Chlorella sorokiniana (10⁶, 10⁷, and 10⁸ C. sorokiniana cells mL⁻¹). Moreover, the qPCR method was applied successfully to the monitoring of P. malhamensis population dynamics in Chlorella cultures in 100 L open ponds. Finally, the qPCR method was applied to the detection of this flagellate in the wider environment of the culture facility. It showed that the flagellate was widely distributed in the environment, and we speculate that Poterioochromonas in Chlorella cultures could originate from the air, the water, and the seed cultures. The qPCR method developed therefore proved to have the specificity and efficiency to be useful for early detection of P. malhamensis in industrial-scale Chlorella cultivation.

马尔汉姆波氏无脊椎动物是一种鞭毛食草动物，很容易污染小球藻培养物，并且可能会对它们产生毁灭性影响，尤其是在大规模培养中。在这里，我们开发了一种定量实时聚合酶链反应（qPCR）方法，用于从高密度小球藻培养物中检测和定量疟原虫。筛选了一组特异于疟原虫线粒体细胞色素氧化酶亚基I基因（COI）的引物，并全面表征了其对田间样品的特异性，敏感性和适用性。结果表明，这些引物具有足够的特异性以区分疟原虫从各种各样的微真核生物，其经常与共存P. malhamensis在微藻培养物，和可以检测非常低浓度P. malhamensis从高浓度的小球藻sorokiniana（10 ⁶，10 ⁷，和10 ^8个 C. sorokiniana细胞mL ^-1）。此外，qPCR方法已成功应用于监测小球藻中疟原虫的种群动态。100 L开放池塘中进行养殖。最后，将qPCR方法应用于在更广泛的培养设施环境中检测鞭毛。这表明，鞭毛广泛分布于环境中，我们推测Poterioochromonas在小球藻培养能够从空气，水和种子培养起源。因此，开发的qPCR方法被证明具有特异性和效率，可用于工业规模小球藻培养中早期检测疟原虫。