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Characterization and Purification of a Phytotoxin Produced by Fusarium solani, the Causal Agent of Soybean Sudden Death Syndrome. H. Jin, Department of Crop Sciences, University of Illinois at Urbana-Champaign (UIUC); G. L. Hartman(2), C. D. Nickell(3), and J. M. Widholm(4). (3)(4)Department of Crop Sciences, University of Illinois at Urbana-Champaign (UIUC); (2)USDA/ARS and Department of Crop Sciences, UIUC, Urbana 61801-4723. Phytopathology 86:277-282. Accepted for publication 19 December 1995. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1996. DOI: 10.1094/Phyto-86-277.

A phytotoxic polypeptide identified in culture filtrates of Fusarium solani, the causal agent of soybean sudden death syndrome, was heat unstable, negatively charged, absorbed by 10% charcoal, and destroyed by proteinase K. The toxicity of the culture filtrates and fractions obtained during purification was bioassayed by measuring browning of soybean calli. Purification of the phytotoxin was achieved by Sephadex G-50 gel filtration chromatography followed by ion exchange chromatography on a DE-52 column. The purified protein migrated as a single band on sodium dodecyl sulfate-polyacrylamide gels with an estimated molecular weight of 17,000. The sequence of the N-terminal 15 amino acids was determined and indicated that a peptide was present. Samples containing this single protein caused browning of soybean calli, necrosis on detached soybean cotyledons and leaves, and yellowing, curling, and drying of attached soybean cotyledons and leaves.