Inami Keigo, Kashiwa Takeshi, Kawabe Masato, Onokubo-Okabe Akiko, Ishikawa Nobuko, Pérez Enrique Rodríguez, Hozumi Takuo, Caballero Liliana Aragón, de Baldarrago Fatima Cáceres, Roco Mauricio Jiménez, Madadi Khalid A, Peever Tobin L, Teraoka Tohru, Kodama Motoichiro, Arie Tsutomu
Graduate school of Agriculture, Tokyo University of Agriculture and Technology.
Microbes Environ. 2014;29(2):200-10. doi: 10.1264/jsme2.me13184. Epub 2014 Jun 6.
Fusarium oxysporum is an ascomycetous fungus that is well-known as a soilborne plant pathogen. In addition, a large population of nonpathogenic F. oxysporum (NPF) inhabits various environmental niches, including the phytosphere. To obtain an insight into the origin of plant pathogenic F. oxysporum, we focused on the tomato (Solanum lycopersicum) and its pathogenic F. oxysporum f. sp. lycopersici (FOL). We collected F. oxysporum from wild and transition Solanum spp. and modern cultivars of tomato in Chile, Ecuador, Peru, Mexico, Afghanistan, Italy, and Japan, evaluated the fungal isolates for pathogenicity, VCG, mating type, and distribution of SIX genes related to the pathogenicity of FOL, and constructed phylogenies based on ribosomal DNA intergenic spacer sequences. All F. oxysporum isolates sampled were genetically more diverse than FOL. They were not pathogenic to the tomato and did not carry SIX genes. Certain NPF isolates including those from wild Solanum spp. in Peru were grouped in FOL clades, whereas most of the NPF isolates were not. Our results suggested that the population of NPF isolates in FOL clades gave rise to FOL by gaining pathogenicity.
尖孢镰刀菌是一种子囊菌，作为一种土传植物病原菌而广为人知。此外，大量非致病性尖孢镰刀菌（NPF）存在于包括植物圈在内的各种环境生态位中。为深入了解植物致病性尖孢镰刀菌的起源，我们聚焦于番茄（Solanum lycopersicum）及其致病性尖孢镰刀菌番茄专化型（FOL）。我们从智利、厄瓜多尔、秘鲁、墨西哥、阿富汗、意大利和日本的野生和过渡型茄属植物以及现代番茄品种中采集了尖孢镰刀菌，评估了真菌分离株的致病性、营养体亲和群（VCG）、交配型以及与FOL致病性相关的六个基因的分布，并基于核糖体DNA基因间隔序列构建了系统发育树。所有采样的尖孢镰刀菌分离株在基因上比FOL更为多样。它们对番茄无致病性且不携带六个基因。某些NPF分离株，包括来自秘鲁野生茄属植物的分离株，被归入FOL分支，而大多数NPF分离株则未被归入。我们的结果表明，FOL分支中的NPF分离株群体通过获得致病性而产生了FOL。
