Phloem-limiting phytoplasmas are known to be causal agents of phyllody, which is recognized by the abnormal development of floral structures resulting in serious yield losses in sesame plants. Currently, identification of the various groups of phytoplasmas that cause sesame phyllody (SP) is conducted by nested PCR, RFLP, and multiplex real-time qPCR assays. However, these methods require intensive labor and are costly and time-consuming so can only be undertaken in well-equipped labs. Here, diagnostic loop-mediated isothermal amplification (LAMP)–based assays allowing rapid detection of specific groups of phytoplasmas within 30 min were developed based on detection of the 16S rRNA sequence of phytoplasmas. Universal 16S rRNA phytoplasma primers and seven primer sets of different 16Sr group phytoplasmas (16SrI, 16SrII, 16SrIII, 16SrIV, 16SrV, 16SrX, 16SrXI) and universal plant cytochrome oxidase (cox) gene primers were used to detect 16S rRNA group phytoplasma sequences and the cox gene in sesame plants. The LAMP assays were carried out using a real-time fluorometer with amplification plots and annealing curves visualized directly. Results demonstrated that the 16SrI and 16SrII group phytoplasmas were causal agents of sesame phyllody in Vietnam. LAMP-based assays for in-field detection of sesame phyllody-causing phytoplasmas revealed advantages and potential applicability in comparison with conventional approaches. To the best of our knowledge, this is the first assessment of multiple phytoplasma infection associated with sesame phyllody disease in Vietnam using LAMP-based assays.

已知韧皮部限制植原体是叶状病的致病因子，其通过花结构的异常发育而被识别，导致芝麻植物的严重产量损失。目前，通过巢式 PCR、RFLP 和多重实时 qPCR 检测对引起芝麻叶 (SP) 的各种植原体进行鉴定。然而，这些方法需要大量的劳动力，而且成本高且耗时，因此只能在设备齐全的实验室中进行。在这里，基于对植原体 16S rRNA 序列的检测，开发了基于诊断环介导的等温扩增 (LAMP) 的检测方法，可以在 30 分钟内快速检测特定的植原体组。通用 16S rRNA 植原体引物和七组不同 16Sr 组植原体（16SrI、16SrII、16SrIII、16SrIV、16SrV、16SrX、cox )基因引物检测芝麻植株16S rRNA组植原体序列和cox基因。LAMP 检测是使用实时荧光计进行的，扩增图和退火曲线直接可视化。结果表明，16SrI 和 16SrII 组植原体是越南芝麻叶病的病原体。与传统方法相比，基于 LAMP 的芝麻叶状植原体现场检测分析显示出优势和潜在的适用性。据我们所知，这是首次使用基于 LAMP 的检测方法对越南与芝麻叶病相关的多种植原体感染进行评估。