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Role of Cellular Permeability Alterations and Pectic and Cellulolytic Enzymes in the Maceration of Carnation Tissue by Pseudomonas caryophylli and Corynebacterium sp.. Chelston W. D. Brathwaite, Graduate Assistant, Department of Plant Pathology, Cornell University, Ithaca, New York 14850, Present address of senior author: Food and Agriculture Organization of the United Nations, Rome, Italy; Robert S. Dickey, Professor, Department of Plant Pathology, Cornell University, Ithaca, New York 14850. Phytopathology 61:476-483. Accepted for publication 16 November 1970. DOI: 10.1094/Phyto-61-476.

Growth of Corynebacterium sp. and activity of endopolygalacturonate trans-eliminase (endo-PGTE) were greater in detached carnation leaf tissue simultaneously inoculated with Pseudomonas caryophylli and Corynebacterium sp. than in tissue inoculated with Corynebacterium sp. alone. Tissue was macerated by culture filtrates of Corynebacterium sp. which contained both endo-PGTE and cellulase. Maceration paralleled the endo-PGTE activity of culture filtrates, but was apparently unrelated to cellulolytic activity. Bathing solutions from leaf tissue inoculated with P. caryophylli contained more amino nitrogen, phosphorus, and potassium and supported greater growth of Corynebacterium sp. than did those from noninoculated tissue or tissue inoculated with Corynebacterium sp. Growth of Corynebacterium sp. in a basal medium containing glucose was dependent on a supply of amino nitrogen and growth in synthetic media, and in bathing solutions from P. caryophylli-infected tissue was related to the amino nitrogen content. It is suggested that enhanced growth of Corynebacterium sp. in tissue simultaneously inoculated with P. caryophylli and Corynebacterium sp. occurs because P. caryophylli causes an increase in the cellular permeability of the tissue, resulting in the release of nutrients from the plant cells which permit growth of Corynebacterium sp. Growth of Corynebacterium sp. is accompanied by synthesis of endo-PGTE which macerates carnation tissue.