The Key Laboratory for Silviculture and Conservation of the Ministry of Education, Beijing Forestry University, Beijing 100083, P.R. China.
Zhouqu County Forestry and Grassland Technology Comprehensive Service Station, Zhouqu 746300, P.R. China.
Plant Dis. 2023 Oct;107(10):3026-3036. doi: 10.1094/PDIS-12-22-2982-RE. Epub 2023 Oct 12.
Chinese white pine, , is a source of high-quality timber and an afforestation tree in China, which plays an important ecological and social role in water and soil conservation. Recently, a new canker disease has been reported in Longnan City, Gansu Province, where is mainly distributed. In this study, the causal agent was isolated from diseased samples and identified as a fungal pathogen, , based on morphological characteristics and molecular analyses (internal transcribed spacer, large subunit, RNA polymerase II, and translation elongation factor-1α). Pathogenicity tests on revealed that isolates caused a 60% average mortality rate in artificially inoculated 2-year-old seedlings. The pathogenicity of these isolates was also observed on the branches of 10-year-old trees with a 100% mortality rate. These results agree with the isolation of from diseased plants, suggesting the possible role of this fungus in the decline of plants. Mycelial growth of was fastest on potato dextrose agar medium, and growth occurred at pH values ranging from 4.0 to 11.0 with temperatures between 5 and 40°C. The fungus also grew rapidly in complete darkness compared with other light conditions. Of the eight carbon and seven nitrogen sources tested, starch and sodium nitrate, respectively, were highly efficient in supporting the mycelial growth of . The ability of to grow at low temperatures (5°C) may explain its occurrence in the Longnan area of Gansu Province. This article is the first report of as an important fungal pathogen causing branch and stem cankers on tree species, which remains a threat to the forests
中国白皮松是中国一种优质木材的来源和造林树种，在中国的水土保持中发挥着重要的生态和社会作用。最近，甘肃省陇南市报告了一种新的溃疡病，主要分布在中国白皮松。本研究从病样中分离出病原菌，根据形态特征和分子分析（内部转录间隔区、大亚基、RNA 聚合酶 II 和翻译延伸因子-1α），鉴定为真菌病原体。对的致病性试验表明，分离株在人工接种的 2 年生幼苗中引起 60%的平均死亡率。在 10 年生的白皮松树枝上也观察到这些分离株的致病性，死亡率为 100%。这些结果与从病株中分离出的结果一致，表明该真菌可能在白皮松植物的衰退中起作用。在马铃薯葡萄糖琼脂培养基上，的菌丝生长最快，在 pH 值为 4.0 到 11.0 之间，温度在 5 到 40°C 之间，生长。与其他光照条件相比，该真菌在完全黑暗中也能迅速生长。在所测试的 8 种碳源和 7 种氮源中，淀粉和硝酸钠分别对支持菌丝生长最有效。能够在低温（5°C）下生长可能解释了它在甘肃省陇南地区的发生。本文首次报道了作为一种重要的真菌病原体，引起白皮松树枝和树干溃疡，这仍然是森林的威胁。
