Institute of Horticultural Production Systems, Section Phytomedicine, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany.
Institute of Horticultural Production Systems, Section of Woody Plant and Propagation Physiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany.
Sci Rep. 2020 Dec 29;10(1):22410. doi: 10.1038/s41598-020-79878-8.
Replant disease is a worldwide phenomenon affecting various woody plant genera and species, especially within the Rosaceae. Compared to decades of intensive studies regarding replant disease of apple (ARD), the replant disease of roses (RRD) has hardly been investigated. The etiology of RRD is also still unclear and a remedy desperately needed. In greenhouse pot trials with seedlings of the RRD-sensitive rootstock Rosa corymbifera 'Laxa' cultured in replant disease affected soils from two different locations, early RRD symptom development was studied in fine roots. In microscopic analyses we found similarities to ARD symptoms with regards to structural damages, impairment in the root hair status, and necroses and blackening in the cortex tissue. Examinations of both whole mounts and thin sections of fine root segments revealed frequent conspicuous fungal infections in association with the cellular disorders. Particularly striking were fungal intracellular structures with pathogenic characteristics that are described for the first time. Isolated fungi from these tissue areas were identified by means of ITS primers, and many of them were members of the Nectriaceae. In a next step, 35 of these isolates were subjected to a multi-locus sequence analysis and the results revealed that several genera and species were involved in the development of RRD within a single rose plant. Inoculations with selected single isolates (Rugonectria rugulosa and Ilyonectria robusta) in a Perlite assay confirmed their pathogenic relationship to early necrotic host plant reactions, and symptoms were similar to those exhibited in ARD.
再植病害是一种全球性现象，影响着各种木本植物属和种，尤其是蔷薇科。与几十年来对苹果再植病（ARD）的深入研究相比，玫瑰再植病（RRD）几乎没有得到研究。RRD 的病因也尚不清楚，急需治疗方法。在温室盆栽试验中，用来自两个不同地点的受再植病影响的土壤培养 RRD 敏感砧木 Rosa corymbifera 'Laxa' 的幼苗，研究了细根中的早期 RRD 症状发展。在显微镜分析中，我们发现与 ARD 症状在结构损伤、根毛状态受损以及皮层组织坏死和变黑方面存在相似之处。对细根段的整体装片和薄片检查显示，与细胞紊乱相关的频繁明显真菌感染。特别引人注目的是具有致病性特征的真菌细胞内结构，这是首次描述。从这些组织区域分离的真菌通过 ITS 引物进行鉴定，其中许多是 Necretiaccae 科的成员。在下一步中，对其中的 35 个分离物进行了多基因序列分析，结果表明，在单个玫瑰植物中，有几个属和种参与了 RRD 的发展。在珍珠岩测定中用选定的单一分离物（Rugonectria rugulosa 和 Ilyonectria robusta）接种证实了它们与早期坏死宿主植物反应的致病性关系，并且症状与 ARD 中表现出的症状相似。
