Toxicity, pathogenicity, and genetic differentiation of five species of Fusarium from sorghum and millet

• Published in: Phytopathology Vol. 95; no. 3; pp. 275 - 283
• Main Authors: Leslie, J.F, Zeller, K.A, Lamprecht, S.C, Rheeder, J.P, Marasas, W.F.O
• Format: Journal Article
• Language: English
• Published: St. Paul, MN American Phytopathological Society 01.03.2005
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; fungal diseases of plants; Fungal plant pathogens; Fusarium; Fusarium andiyazi; Fusarium nygamai; Fusarium pseudonygamai; Fusarium thapsinum; Fusarium verticilloides; genetic variation; grain sorghum; millets; pathogenicity; Pathogens; pathotypes; Pennisetum glaucum; Phytopathology. Animal pests. Plant and forest protection; plant pathogenic fungi; Sorghum; Sorghum bicolor; strain differences; symptoms; toxicity; Australia; South Africa; Namibia; Monocotyledones; Plant pathology; Microbiology; Plant pathogen; Toxicity; Sorghum; Fungi; Pathogenicity; Gramineae; Angiospermae; Fusarium; Genetics; Herbaceous plant; Spermatophyta; Specific identification; Fungi Imperfecti; Thallophyta
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/PHYTO-95-0275

Fusarium isolates recovered from sorghum and millet are commonly identified as F. moniliforme, but with the recognition of new species in this group, the strains given this name are being re-evaluated. We analyzed five strains each from five Fusarium species (F. andiyazi, F. nygamai, F. pseudonygamai, F. thapsinum, and F. verticillioides) often associated with sorghum and millet for their ability to produce fumonisin and moniliformin, their toxicity to ducklings, and their ability to cause disease on sorghum seedlings in vitro. These species can be distinguished with isozymes (fumarase, NADP-dependent isocitrate dehydrogenase, and malate dehydrogenase) and with banding patterns resulting from amplified fragment length polymorphisms. Two species, F. pseudonygamai and F. thapsinum, produced high levels of moniliformin, but little or no fumonisins, and were consistently highly toxigenic in the duckling tests. Two species, F. verticillioides and F. nygamai, produced high levels of fumonisins, but little or no moniliformin, and also were toxigenic in the duckling tests. F. andiyazi produced little or no toxin and was the least toxigenic in the duckling tests. In sorghum seedling pathogenicity tests, F. thapsinum was the most virulent followed by F. andiyazi, then F. verticillioides, and finally F. nygamai and F. pseudonygamai, which were similar to each other. Thus, these five species, which would once have all been called F. moniliforme, differ sufficiently in terms of plant pathogenicity and toxin production profile, that their previous misidentification could explain inconsistencies in the literature and differences observed by researchers who thought they were all working with the same fungal species.