PDF(Pubmed)
Abstract：
Increased drought combined with emerging pathogens poses an increased threat to forest health. This is attributable to the unpredictable behaviour of forest pathosystems, which can favour fungal pathogens over the host under persistent drought stress conditions. Diplodia sapinea (≡ Sphaeropsis sapinea) is one of the most severe pathogens in Scots pine (Pinus sylvestris) causing Diplodia tip blight (conifer blight) under certain environmental conditions. Recently, the fungus has also been isolated from non-conifer hosts, indicating that it has a broader host range than previously known. In this study we compared the impact of different levels of water availability on necrosis length caused by D. sapinea strains isolated as endophytes (eight strains isolated from asymptomatic Scots pine) and pathogens (five strains isolated from symptomatic Scots pine) and five strains isolated from symptomatic non-pine hosts. For all strains the decreased water availability increased the necrosis length in Scots pine shoots. The isolates from non-pine hosts caused the most severe reactions under all water availabilities. The results of the study indicate the likelihood that effects of climatic changes such as drought will drive D. sapinea damage in Scots pine-dominated forests and increase mortality rates in affected trees. Further, the higher necrosis in the Scots pines caused by strains that had performed a host switch are concerning with regard to future scenarios thus increasing infection pressure on Scots pine from unknown sources.
摘要：
干旱加剧加上新出现的病原体对森林健康构成了更大的威胁。这是由于森林病理系统的不可预测的行为，在持续的干旱胁迫条件下，可以使真菌病原体胜过宿主。Diplodiasapinea（=Sphaeropsissapinea）是苏格兰松树（Pinussylvestris）中最严重的病原体之一，在某些环境条件下引起Diplodia尖端疫病（针叶病）。最近,这种真菌也是从非针叶树宿主中分离出来的，表明它具有比以前已知的更广泛的宿主范围。在这项研究中，我们比较了不同水平的水利用率对由内生菌分离的D.sapinia菌株（从无症状的苏格兰松树中分离出的8个菌株）和病原体（从有症状的苏格兰松树中分离出的5个菌株）和从有症状的非松树宿主中分离出的5个菌株引起的坏死长度的影响。对于所有菌株，水的利用率降低会增加苏格兰松树芽的坏死长度。来自非松树宿主的分离物在所有水可用性下引起最严重的反应。研究结果表明，干旱等气候变化的影响可能会在以松树为主的苏格兰森林中造成D.sapinia的破坏，并增加受影响树木的死亡率。Further,关于未来的情况，由进行宿主转换的菌株引起的苏格兰松树中较高的坏死率令人担忧，从而增加了未知来源的苏格兰松树的感染压力。
