Ramos Madalena, Carvalho Rita, Soares da Silva Elsa, Ramos Ana Paula, Talhinhas Pedro
LEAF, Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017 Lisbon, Portugal.
LPVVA, Laboratório de Patologia Vegetal "Veríssimo de Almeida", Instituto Superior de Agronomia, Universidade de Lisboa. 1349-017 Lisbon, Portugal.
Plants (Basel). 2020 Mar 31;9(4):427. doi: 10.3390/plants9040427.
Daylily rust-caused by -was confined to Eastern Asia until the disease was reported in Oceania, Africa, the Americas and Portugal in the 21st century. Although information on rust resistance of American cultivars is available, little is known about the resistance of European bred cultivars, threating the ornamental sector if the fungus spreads to other European countries. Aiming to provide tools to address this, we analyzed the Portuguese pathogens and characterized rust resistance in a selection of cultivars, while optimizing disease rating scales. Morphologic, genetic and cytogenomic characterization of four isolates reveals narrow diversity and raises the question whether the pathogen may have originated in North- or Central America. Daily records of multiple symptomatologic parameters enabled a detailed disease progress analysis, discriminating cultivars according to their resistance levels and revealing susceptibility as the most common state. Among the tested cultivars, 12 out of 17 began to show symptoms between 6-8 dai and were classified as susceptible. Cultivars 'Stella d'Oro', 'Bitsy' and 'Cherry Tiger' behaved as moderately resistant although the occurrence of late sporulation on leaves suggests incomplete resistance and challenges common rating scales. The identification of resistance sources in European breeding lines is crucial for the sustainable future of daylilies.
萱草锈病——由[病原体名称未给出]引起——在21世纪被报道出现在大洋洲、非洲、美洲和葡萄牙之前，一直局限于东亚地区。尽管有关于美国栽培品种锈病抗性的信息，但对于欧洲培育品种的抗性却知之甚少，如果这种真菌传播到其他欧洲国家，将会对观赏植物产业构成威胁。为了提供应对这一问题的工具，我们分析了葡萄牙的病原体，并在一系列品种中对锈病抗性进行了表征，同时优化了病害评级标准。对四个分离株的形态学、遗传学和细胞基因组学表征显示出多样性狭窄，并引发了病原体是否可能起源于北美或中美洲的问题。对多个症状学参数的每日记录使得能够进行详细的病害进展分析，根据品种的抗性水平对其进行区分，并揭示出易感性是最常见的状态。在测试的品种中，17个品种中有12个在接种后6 - 8天开始出现症状，并被归类为易感品种。‘Stella d'Oro’、‘Bitsy’和‘Cherry Tiger’品种表现为中度抗性，尽管叶片上后期出现孢子形成表明抗性不完全，并对常见的评级标准提出了挑战。在欧洲育种系中鉴定抗性来源对于萱草的可持续未来至关重要。
