VIEW ARTICLE

Physiology and Biochemistry

Partial Characterization of Phytotoxic Polysaccharides Produced in vitro by Colletotrichum trifolii. Kurt A. Frantzen, Department of Plant Pathology, Kansas State University, Manhattan 66506, Present address of the senior author: Laboratory of Agricultural Biochemistry, University of Nebraska, Lincoln 68583; Lowell B. Johnson(2), and Donald L. Stuteville(3). (2)(3)Department of Plant Pathology, Kansas State University, Manhattan 66506. Phytopathology 72:568-573. Accepted for publication 19 August 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-568.

Polysaccharides produced in vitro by Colletotrichum trifolii caused paling, desiccation, wilting, and death of excised leaves, shoots, and seedlings of alfalfa (Medicago sativa). They were partially purified by acetone precipitation, ultrafiltration, and column chromatography. All three C. trifolii isolates tested produced similar phytotoxic polysaccharides. Symptoms were induced in cuttings of susceptible (Kanza) and resistant (Arc) alfalfa, tomato, corn, and soybean, and a hypersensitivelike response was elicited on soybean cotyledons and bean hypocotyls. Partially purified materials were 98–99% carbohydrate and 1–2% protein. Galactose, mannose, glucose, and a trace of a probable uronic acid were found in hydrolysates. Toxic activity was reduced by periodate oxidation or treating with α-mannosidase or β-galactosidase, and was totally removed by hydrolysis. Proteinase K, autoclaving, or pH of 2 or 11 did not alter activity. Excised alfalfa leaves fed commercial dextrans (40 to 500 × 10³ daltons) developed symptoms similar to those induced by the C. trifolii polysaccarides.