Late blight caused by Phytophthora infestans is the most devastating potato disease, yet leaf infections are not reliably detected by current assays during the incubation phase of the pathogen and asymptomatic plants. In this study, the genome of P. infestans was queried against the NCBI nucleic acid database and a 1050 bp species-specific DNA fragment was identified. Using this fragment, polymerase chain reaction (PCR) and recombinase-aided amplification-lateral flow dipstick (RAA-LFD) assays were developed for the detection of potato late blight pathogen. Both assays effectively distinguished P. infestans from related species (e.g., P. capsici). The detection limits of the three PCR primer pairs under optimized conditions (59.3 °C, 35 PCR cycles) were 1.31 × 10⁻¹ fg, 1.18 × 10⁻² fg, and 1.24 × 10⁻¹ fg, corresponding to 27.31 copies, 2.49 copies, and 25.51 copies, respectively. While the detection limit of the RAA-LFD assay at 37 °C for 25 min was 5 × 10⁻⁴ fg (0.10 copies), which was better than all reported molecular detection assays for potato late blight. Both PCR (59.3 °C, 35 PCR cycles) and RAA-LFD (37 °C for 10 min) positively detected all symptomatic leaves. When extending the amplification time to 20 min, the RAA-LFD assay detected most of the leaves with incubation phase of the disease. The molecular detection assays developed in this study were species-specific and are expected to be used in detecting potato late blight in the incubation phase in leaves and asymptomatic plants, which will aid in accurate monitoring and early warning of potato late blight.

由致病疫霉引起的晚疫病是最具破坏性的马铃薯病害，但在病原体和无症状植物的孵化阶段，目前的检测方法无法可靠地检测到叶片感染。在这项研究中，针对 NCBI 核酸数据库查询了致病疫霉的基因组，并确定了一个 1050 bp 的物种特异性 DNA 片段。使用该片段，聚合酶链反应 (PCR) 和重组酶辅助扩增侧向流动试纸 (RAA-LFD) 测定法被开发用于检测马铃薯晚疫病病原体。两种测定都有效地区分致病疫霉与相关物种（例如，辣椒疫霉). 三个 PCR 引物对在优化条件下（59.3 °C，35 个 PCR 循环）的检测限分别为 1.31 × 10 -1 ^fg  、1.18 × 10 ^-2  fg 和 1.24 × 10 ^-1  fg，对应于 27.31 拷贝、2.49份和 25.51 份。虽然 RAA-LFD 测定在 37 °C 下 25 分钟的检测限为 5 × 10 ^-4 fg（0.10 拷贝），优于所有报道的马铃薯晚疫病分子检测分析。PCR（59.3 °C，35 个 PCR 循环）和 RAA-LFD（37 °C，10 分钟）均检测到所有有症状的叶子。当将扩增时间延长至 20 分钟时，RAA-LFD 测定检测到大部分处于疾病潜伏期的叶片。本研究开发的分子检测方法具有种属特异性，有望用于马铃薯叶片和无症状植株孵化期晚疫病的检测，有助于马铃薯晚疫病的准确监测和预警。