Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 27, FIN-00014, Helsinki, Finland.
Department of Environmental and Biological Sciences, Kuopio Campus, University of Eastern Finland (UEF), P.O. Box 1627, FIN-70211, Kuopio, Finland.
BMC Plant Biol. 2019 Jan 3;19(1):2. doi: 10.1186/s12870-018-1602-0.
Root and butt rot of conifer trees caused by fungi belonging to the Heterobasidion annosum species complex is one of the most economically important fungal diseases in commercial conifer plantations throughout the Northern hemisphere. We investigated the interactions between Heterobasidion fungi and their host by conducting dual RNA-seq and chemical analysis on Norway spruce trees naturally infected by Heterobasidion spp. We analyzed host and pathogen transcriptome and phenolic and terpenoid contents of the spruce trees.
Presented results emphasize the role of the phenylpropanoid and flavonoid pathways in the chemical defense of Norway spruce trees. Accumulation of lignans was observed in trees displaying symptoms of wood decay. A number of candidate genes with a predicted role in the higher level regulation of spruce defense responses were identified. Our data indicate a possible role of abscisic acid (ABA) signaling in the spruce defense against Heterobasidion infection. Fungal transcripts corresponding to genes encoding carbohydrate- and lignin-degrading enzymes, secondary metabolism genes and effector-like genes were expressed during the host colonization.
Our results provide additional insight into defense strategies employed by Norway spruce trees against Heterobasidion infection. The potential applications of the identified candidate genes as markers for higher resistance against root and butt rot deserve further evaluation.
由属于 Heterobasidion annosum 种复合体的真菌引起的针叶树的根和基腐病是北半球商业针叶树种植园中最具经济重要性的真菌病害之一。我们通过对自然感染 Heterobasidion spp 的挪威云杉进行双 RNA-seq 和化学分析，研究了 Heterobasidion 真菌与其宿主之间的相互作用。我们分析了宿主和病原体的转录组以及云杉的酚类和萜烯含量。
本研究强调了苯丙烷和类黄酮途径在挪威云杉化学防御中的作用。在表现出木材腐烂症状的树木中观察到木质素的积累。鉴定了一些具有预测作用的候选基因，这些基因可能在云杉防御反应的高级调控中发挥作用。我们的数据表明，脱落酸（ABA）信号可能在云杉对 Heterobasidion 感染的防御中发挥作用。在宿主定殖过程中，编码碳水化合物和木质素降解酶、次生代谢基因和效应子样基因的真菌转录本被表达。
我们的研究结果为挪威云杉对 Heterobasidion 感染的防御策略提供了更多的见解。鉴定出的候选基因作为对根和基腐病更高抗性的标记的潜在应用值得进一步评估。
