Opium poppy, belonging to the family Papaveraceae, is grown for its alkaloid compounds of pharmaceutical value. Downy mildew caused by Peronospora somniferi and Pe. meconopsidis, substantially impacts crop production. The present study was conducted to identify the host range of Pe. somniferi and Pe. meconopsidis within selected weed and ornamental members of the Papaveraceae family. Nine Papaver spp., Meconopsis cambrica and a nonhost control (tomato, Solanum lycopersicum) were challenged with both pathogens under controlled glasshouse or laboratory conditions using infested soil or foliar applied sporangia as inocula. Peronospora somniferi and Pe. meconopsidis induced disease symptoms, including sporulation, in at least one trial for all tested species except for Pa. atlanticum and tomato. Species‐specific PCR testing of foliage of challenged plants confirmed infections by both pathogen species of symptomatic plants, identifying these as hosts. Positive PCR tests were also obtained from Pa. atlanticum plants for both pathogens. However, in the absence of pathogen sporulation structures as further evidence of infection, the host status of Pa. atlanticum remains inconclusive. Testing of seeds collected from Pe. somniferi and Pe. meconopsidis infected plants of Pa. somniferum, Pa. dubium, Pa. rhoeas and Pa. nudicaule showed presence of both pathogens, indicating likely ability for seed transmission in these species. We identified new hosts of these pathogens and discuss potential implications of these alternative hosts in pathogen survival, dissemination and epidemic initiation.

中文翻译：

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Peronospora somniferi 和 Pe 的寄主范围。在受控条件下，选定的罂粟科成员中的 meconopsidis

罂粟属于罂粟科，因其具有药用价值的生物碱化合物而种植。霜霉病是由睡梦霜霉和 Pe 引起的。meconopidis，严重影响作物生产。本研究旨在确定 Pe 的寄主范围。催眠和佩。选定的杂草和罂粟科观赏植物中的 meconopsidis。在受控温室或实验室条件下，使用受感染的土壤或叶面施用的孢子囊作为接种物，用这两种病原体攻击九种罂粟属植物、绒毛绿绒蒿和一种非寄主对照（番茄、茄属植物）。Peronospora somniferi 和 Pe。至少在一项试验中，除 Pa. atlanticum 和番茄外，所有受试物种均由 meconopidis 诱发疾病症状，包括孢子形成。受攻击植物叶子的物种特异性 PCR 测试证实了有症状植物的两种病原体物种的感染，并将它们识别为宿主。还从 Pa. atlanticum 植物中获得了两种病原体的阳性 PCR 测试。然而，在没有病原体孢子形成结构作为感染的进一步证据的情况下，Pa. atlanticum 的宿主状态仍然没有定论。测试从 Pe 收集的种子。催眠和佩。meconopidis 感染的 Pa. somniferum、Pa. dubium、Pa. rhoeas 和 Pa. nudicaule 的植物显示两种病原体的存在，表明这些物种可能具有种子传播的能力。我们确定了这些病原体的新宿主，并讨论了这些替代宿主在病原体存活、传播和流行开始方面的潜在影响。