Native and Forage Grasses – Reservoir of New Fusarium Species
Marileide M. Costa1*, Ludwig H. Pfenning2, Johannes Z. Groenewald1, Pedro W. Crous1
1 Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
2 Department of Plant Pathology, Universidade Federal de Lavras, 37200-900, Lavras MG, Brazil.
Many species of the genus Fusarium show an affinity with Poaceae, where they live in an endophytic association as potential pathogens that may produce mycotoxins. Native or introduced grasses in Brazil and South Africa can represent inoculum reservoirs of already known or new Fusarium species which are potentially plant pathogens, causing loss of yield or quality in crops or livestock. Fusarium strains were obtained from forage grasses in Brazil, including Brachiaria sp. – frequently used in consortia with important crop plants such as maize and sorghum, and from about 30 different native grass species from the Buffelskloof Nature Reserve in South Africa. Strains were characterized by a multi-gene phylogenetic analysis using partial nucleotide gene sequences of three gene regions, namely tef1, rpb2 and CaM, evaluation of morphological characters, host-substrate preference, and geographic distribution. Nine known Fusarium species from three different species complexes were identified from Brazil, and two novel phylogenetic species described within the Fusarium fujikuroi species complex as F. caapi and F. brachiariae. The 50 South African strains obtained belong to 15 distinct Fusarium phylogenetic species from eight different species complexes, of which 10 represent species so far unknown to science. These results show that native and forage grasses harbour not only a high diversity of known species, which can potentially represent pathogens of crops plants like maize, sorghum, rice and sugar cane, but also novel Fusarium species. The latter deserve further study for being potential mycotoxin producers and/or plant pathogens.