VIEW ARTICLE

Physiology and Biochemistry

Partial Purification of Proteinase Inhibitors from Tomato Plants Infected with Phytophthora infestans. T. E. Cleveland, Former graduate research assistant, Department of Plant Pathology and Crop Physiology, Louisiana State University, Agricultural Experiment Station, Baton Rouge 70803, Present address of senior author: Plant Pathology Department, University of Kentucky, Lexington 40546; L. L. Black, professor, Department of Plant Pathology and Crop Physiology, Louisiana State University, Agricultural Experiment Station, Baton Rouge 70803. Phytopathology 73:664-670. Accepted for publication 4 October 1982. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-664.

Chymotrypsin and trypsin inhibitors were partially purified from the leaves of tomato plants (Lycopersicon esculentum) by affinity chromatography and isoelectric focusing 48 hr after inoculation with Phytophthora infestans, tomato race O. Tomato selections 33 (TS 33), incompatible, and 19 (TS 19), compatible, to tomato race O of P. infestans were used in this study. The initial inhibitor activity was greater in uninoculated plants of TS 33 than in TS 19, and overall inhibitor activity declined in both tomato selections after inoculation. Measurements of individual inhibitor activity, after isoelectric focusing, showed that there was a decline in the levels of most inhibitors following inoculation. The same inhibitors were detected in inoculated and uninoculated tomato leaves. The results from this study failed to corroborate a previous report from this laboratory that an increase in proteinase inhibitor activity in crude extracts was associated with the incompatible response of TS 33 inoculated with race O of P. infestans.