Department of Food and Chemical Engineering, Laboratory of Mycology and Phytopathology, Universidad de los Andes, Bogotá, Colombia 27991.
Corporación Colombiana de Investigación Agropecuaria-AGROSAVIA, Centro de Investigación Tibaitatá, Km 14 Via Mosquera-Bogotá, Cundinamarca, Colombia 250047.
Phytopathology. 2022 Aug;112(8):1783-1794. doi: 10.1094/PHYTO-04-21-0158-R. Epub 2022 Jul 8.
Late blight disease, caused by the plant pathogen , is one of the major threats for tomato and potato crops. Monitoring the populations of . is important to determine if there are changes in the sensitivity to fungicides and host preference. In this study, microsatellite markers and mitochondrial haplotypes were used to assess the genotype of isolates of . collected from tomato and potato plants in Colombia. Furthermore, sensitivity to the three fungicides cymoxanil (penetrant fungicide), mefenoxam, and fluopicolide (systemic fungicides), and tomato-potato host preference, were evaluated. Mitochondrial haplotyping showed that isolates collected on tomato were from the genetic groups Ia and Ib, while isolates collected on potatoes belonged to group IIa. Microsatellite analyses showed that isolates from tomato form two groups, including the Ib mitochondrial haplotype (which is genetically close to the US-1 clonal lineage) and the Ia haplotype (related to the EC-3 lineage), whereas Colombian isolates from potato formed a separate group. Furthermore, differences in sensitivity to fungicides were observed. Eighty-one percent of the isolates tested were resistant to mefenoxam with an EC >10 μg ml. Forty-two percent of the isolates showed an intermediate resistance to cymoxanil. The EC values ranged between 1 and 10 μg ml. For fluopicolide, 90% of the isolates were sensitive, with EC <1 μg ml. Host preference assays showed that potato isolates infected both host species. Thus, isolates that infect potatoes may pose a risk for tomato crops nearby.
晚疫病是由植物病原菌引起的，是番茄和马铃薯作物的主要威胁之一。监测 的种群对于确定其对杀菌剂的敏感性是否发生变化以及宿主偏好是否发生变化非常重要。在这项研究中，使用微卫星标记和线粒体单倍型来评估从哥伦比亚番茄和马铃薯植物中收集的 的分离株的基因型。此外，还评估了对三种杀菌剂（杀真菌剂辛菌胺、苯并咪唑杀菌剂甲霜灵和氟啶酰菌胺（系统性杀菌剂））的敏感性以及对番茄-马铃薯的宿主偏好性。线粒体单倍型分析表明，从番茄上分离到的分离物属于遗传组 Ia 和 Ib，而从马铃薯上分离到的分离物属于组 IIa。微卫星分析表明，来自番茄的分离物形成了两个群体，包括 Ib 线粒体单倍型（与美国-1 克隆谱系在遗传上接近）和 Ia 单倍型（与 EC-3 谱系有关），而来自哥伦比亚马铃薯的分离物则形成了一个单独的群体。此外，还观察到对杀菌剂的敏感性存在差异。81%的测试分离物对甲霜灵表现出抗性，EC >10μg ml。42%的分离物对辛菌胺表现出中度抗性。EC 值在 1 到 10μg ml 之间。对于氟啶酰菌胺，90%的分离物敏感，EC <1μg ml。宿主偏好性测定表明，马铃薯分离物感染了两种宿主物种。因此，感染马铃薯的分离物可能对附近的番茄作物构成威胁。
