Institute of Pesticides and Environmental Protection, Belgrade, Serbia.
University of Belgrade, Faculty of Agriculture, Belgrade, Serbia.
Phytopathology. 2019 Nov;109(11):1900-1907. doi: 10.1094/PHYTO-04-19-0138-R. Epub 2019 Oct 2.
Floricolous downy mildews (, oomycetes) are a small, monophyletic group of mostly inconspicuous plant pathogens that induce symptoms exclusively on flowers. Characterization of this group of pathogens, and information about their biology, is particularly sparse. The recurrent presence of a disease causing flower malformation which, in turn, leads to high production losses of the medicinal herb in Serbia has enabled continuous experiments focusing on the pathogen and its biology. was identified as the causal agent of the disease, and morphologically and molecularly characterized. Diseased chamomile flowers showed severe malformations of the disc and ray florets, including phyllody and secondary inflorescence formation, followed by the onset of downy mildew. Phylogeny, based on internal transcribed spacer and 2, indicates clustering of the Serbian with other from chamomile although, in 2 analyses, they formed a separate subcluster. Evidence pointing to systemic infection was provided through histological and molecular analyses, with related experiments validating the impact of soilborne and blossom infections. This study provides new findings in the biology of on chamomile, thus enabling the reconstruction of this floricolous species' life cycle.
花粉疫霉（疫霉目，卵菌门）是一小群单系的植物病原真菌，它们主要引起花朵上的不显眼症状。该病原真菌群的特征以及有关其生物学的信息特别匮乏。在塞尔维亚，一种药用草本植物因引起花朵畸形的病害而反复出现，导致其产量严重损失，这使得人们可以持续关注病原体及其生物学特性。被鉴定为该病害的致病因子，并从形态学和分子学上进行了特征描述。感病的甘菊花朵表现出明显的盘状和舌状花瓣畸形，包括叶状和次生花序的形成，随后出现粉霉病。基于内转录间隔区和 2 的系统发育分析表明，塞尔维亚与其他来自甘菊的聚集成簇，尽管在 2 个分析中，它们形成了一个单独的亚簇。通过组织学和分子分析提供了指向系统性感染的证据，相关实验验证了土传和花传感染的影响。本研究为甘菊上的花粉疫霉生物学提供了新的发现，从而能够重建这种花粉疫霉物种的生活史。
