The Tomato Wilt Fungus <i>Fusarium oxysporum</i> f. sp. <i>lycopersici</i> shares Common Ancestors with Nonpathogenic <i>F. oxysporum</i> isolated from Wild Tomatoes in the Peruvian Andes
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<i>Fusarium oxysporum</i> is an ascomycetous fungus that is well-known as a soilborne plant pathogen. In addition, a large population of nonpathogenic <i>F. oxysporum</i> (NPF) inhabits various environmental niches, including the phytosphere. To obtain an insight into the origin of plant pathogenic <i>F. oxysporum</i>, we focused on the tomato (<i>Solanum lycopersicum</i>) and its pathogenic <i>F. oxysporum</i> f. sp. <i>lycopersici</i> (<i>FOL</i>). We collected <i>F. oxysporum</i> from wild and transition <i>Solanum</i> 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 <i>SIX</i> genes related to the pathogenicity of <i>FOL</i>, and constructed phylogenies based on ribosomal DNA intergenic spacer sequences. All <i>F. oxysporum</i> isolates sampled were genetically more diverse than <i>FOL</i>. They were not pathogenic to the tomato and did not carry <i>SIX</i> genes. Certain NPF isolates including those from wild <i>Solanum</i> spp. in Peru were grouped in <i>FOL</i> clades, whereas most of the NPF isolates were not. Our results suggested that the population of NPF isolates in <i>FOL</i> clades gave rise to <i>FOL</i> by gaining pathogenicity.
- Microbes and Environments
Microbes and Environments 29(2), 200-210, 2014
Japanese Society of Microbial Ecology · The Japanese Society of Soil Microbiology