Wu WenXia, Chen ShuaiFei
China Eucalypt Research Centre (CERC), Chinese Academy of Forestry (CAF), Zhanjiang 524022, China.
Nanjing Forestry University (NJFU), Nanjing 210037, China.
J Fungi (Basel). 2021 Jan 20;7(2):73. doi: 10.3390/jof7020073.
Many species are causal agents of diseases on several forestry, agricultural and horticultural crops. leaf blight is one of the most important diseases associated with plantations and nurseries in Asia and South America. Recently, symptoms of leaf rot and leaf blight caused by species were observed in a one-year-old experimental plantation in GuangXi Province, southern China. To better understand the species diversity, mating strategy and pathogenicity of species isolated from diseased tissues and soils, diseased leaves and soils under the trees from ten hybrid genotypes were collected. Three hundred and sixty-eight isolates were obtained from diseased leaves and soils under these trees, and 245 representative isolates were selected based on the sampling substrates and genotypes and identified by DNA sequence analyses based on the translation elongation factor 1-alpha (), β-tubulin (), calmodulin () and histone H3 () gene regions, as well as a combination of morphological characteristics. These isolates were identified as (50.2%), (47.4%), (1.6%), (0.4%) and (0.4%). This is the first report of and occurrence in China. was isolated from both diseased leaves and soils; the other four species were only obtained from soils. and gene amplification and mating type assignment results showed that is heterothallic and an asexual cycle represents the primary reproductive mode, and are likely to be heterothallic and and are homothallic. Based on the genetic diversity comparisons for isolates from diseased leaves and soils, we hypothesize that in soils was spread from diseased leaves. Both the mycelia plug and conidia suspension inoculations indicated that all five species were pathogenic to the two genotypes tested and the tolerance of the two genotypes differed. It is necessary to understand the ecological niche and epidemiological characteristics of these species and to select disease resistant genotypes in southern China in the future.
许多物种是多种林业、农业和园艺作物病害的病原体。叶枯病是亚洲和南美洲与种植园和苗圃相关的最重要病害之一。最近，在中国南方广西省的一个一年生实验种植园中观察到了由该物种引起的叶腐病和叶枯病症状。为了更好地了解从患病组织和土壤中分离出的该物种的物种多样性、交配策略和致病性，收集了来自10个杂交基因型树下的患病叶片和土壤。从这些树下的患病叶片和土壤中获得了368个分离株，并根据采样基质和基因型选择了245个代表性分离株，通过基于翻译延伸因子1-α（）、β-微管蛋白（）、钙调蛋白（）和组蛋白H3（）基因区域的DNA序列分析以及形态特征的组合进行鉴定。这些分离株被鉴定为（50.2%）、（47.4%）、（1.6%）、（0.4%）和（0.4%）。这是在中国首次报道和的发生情况。从患病叶片和土壤中均分离出；其他四个物种仅从土壤中获得。和基因扩增及交配型分配结果表明是异宗配合的，无性循环是主要繁殖方式，和可能是异宗配合的，而和是同宗配合的。基于对患病叶片和土壤中分离株的遗传多样性比较，我们推测土壤中的是从患病叶片传播而来的。菌丝块和分生孢子悬浮液接种均表明，所有五个物种对测试的两个基因型均具有致病性，且两个基因型的耐受性不同。未来有必要了解这些物种的生态位和流行病学特征，并在中国南方选择抗病基因型。
