| Autor: |
Castroagudín VL; Department of Phytopathology, Rural Engineering, and Soil Science (Departamento de Fitossanidade, Engenharia Rural e Solos), UNESP- University of São Paulo State, Ilha Solteira, São Paulo, Brazil., Moreira SI; Department of Phytopathology, Federal University of Lavras, Lavras, Minas Gerais, Brazil., Pereira DA; Department of Phytopathology, Rural Engineering, and Soil Science (Departamento de Fitossanidade, Engenharia Rural e Solos), UNESP- University of São Paulo State, Ilha Solteira, São Paulo, Brazil;; Plant Pathology Group, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland., Moreira SS; Department of Phytopathology, Rural Engineering, and Soil Science (Departamento de Fitossanidade, Engenharia Rural e Solos), UNESP- University of São Paulo State, Ilha Solteira, São Paulo, Brazil., Brunner PC; Plant Pathology Group, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland., Maciel JL; Brazilian Agriculture Research Corporation-Wheat (EMBRAPA-Trigo), Passo Fundo, Rio Grande do Sul, Brazil., Crous PW; CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.; Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa.; Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands., McDonald BA; Plant Pathology Group, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland., Alves E; Department of Phytopathology, Federal University of Lavras, Lavras, Minas Gerais, Brazil., Ceresini PC; Department of Phytopathology, Rural Engineering, and Soil Science (Departamento de Fitossanidade, Engenharia Rural e Solos), UNESP- University of São Paulo State, Ilha Solteira, São Paulo, Brazil. |
| Abstrakt: |
Pyricularia oryzae is a species complex that causes blast disease on more than 50 species of poaceous plants. Pyricularia oryzae has a worldwide distribution as a rice pathogen and in the last 30 years emerged as an important wheat pathogen in southern Brazil. We conducted phylogenetic analyses using 10 housekeeping loci for 128 isolates of P. oryzae sampled from sympatric populations of wheat, rice, and grasses growing in or near wheat fields. Phylogenetic analyses grouped the isolates into three major clades. Clade 1 comprised isolates associated only with rice and corresponds to the previously described rice blast pathogen P. oryzae pathotype Oryza (PoO). Clade 2 comprised isolates associated almost exclusively with wheat and corresponds to the previously described wheat blast pathogen P. oryzae pathotype Triticum (PoT). Clade 3 contained isolates obtained from wheat as well as other Poaceae hosts. We found that Clade 3 is distinct from P. oryzae and represents a new species, Pyricularia graminis-tritici (Pgt). No morphological differences were observed among these species, but a distinctive pathogenicity spectrum was observed. Pgt and PoT were pathogenic and highly aggressive on Triticum aestivum (wheat), Hordeum vulgare (barley), Urochloa brizantha (signal grass), and Avena sativa (oats). PoO was highly virulent on the original rice host ( Oryza sativa ), and also on wheat, barley, and oats, but not on signal grass. We conclude that blast disease on wheat and its associated Poaceae hosts in Brazil is caused by multiple Pyricularia species. Pyricularia graminis-tritici was recently found causing wheat blast in Bangladesh. This indicates that P. graminis-tritici represents a serious threat to wheat cultivation globally. |
