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Enzymatic Degradation of Potato Cell Walls in Potato Virus X-Free and Potato Virus X-Infected Potato Tubers by Fusarium roseum ‘Avenaceum’. J. M. Mullen, Former Graduate Assistant, Department of Plant Pathology, Cornell University, Ithaca, New York 14853; D. F. Bateman, Professor and Chairman, Department of Plant Pathology, Cornell University, Ithaca, New York 14853. Phytopathology 65:797-802. Accepted for publication 24 February 1975. DOI: 10.1094/Phyto-65-797.

Enzyme preparations from culture filtrates of Fusarium roseum ‘Avenaceum’ or diseased tissue solubilized up to 54.9% of the noncellulosic wall polysaccharides in isolated potato cell walls when incubated together at 30 C for 5 hours at pH 7.0. Cell walls from potato virus X (PVX)-free tubers contained approximately 30% galactose, 26% glucose (cellulose), 16% galacturonic acid, 7% arabinose, 3% xylose, 3% glucuronic acid and 1% rhamnose. Tubers infected with PVX are more resistant to F. roseum ‘Avenaceum’ than PVX-free tubers. The polysaccharide composition of cell walls from PVX-infected tubers was comparable to that of walls from PVX-free tubers except for a decrease in galactose content. F. roseum ‘Avenaceum’ produced polysaccharidases in both PVX-infected and PVX-free tissue. Analysis of cell wall composition in PVX-free tubers infected with F. roseum ‘Avenaceum’ indicated that the noncellulosic cell wall polysaccharides were removed during pathogenesis. Cell walls from PVX-free and PVX-infected tubers were equally susceptible to enzymatic decomposition.