VIEW ARTICLE

Physiology and Biochemistry

Elevation and Release of Cell-Associated Pectate Lyase in Erwinia chrysanthemi by Lithium and Sodium Chloride. John P. Mildenhall, Department of Genetics and Plant Protection, University of Fort Hare, Alice, Ciskei, South Africa; William A. Lindner(2), Bernard A. Prior(3), and Kim Tutt(4). (2)Department of Biochemistry, University of Fort Hare; (3)Department of Microbiology, University of the Orange Free State, Bloemfontein, South Africa; (4)Department of Genetics and Plant Protection, University of Fort Hare, Alice, Ciskei, South Africa. Phytopathology 78:213-217. Accepted for publication 10 August 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/Phyto-78-213.

When Erwinia chrysanthemi was grown at a water activity (a_w) value of 0.990 in the presence of LiCl (1.4% w/v) or NaCl (1.4% w/v), the cell-associated levels of pectate lyase (Pel) were 10- to 20-fold greater than in cells grown in the medium (0.998 a_w) without these salts. Upon addition of these salts to the growth medium during the mid-exponential phase of growth, secretion of extracellular Pel ceased for 60 min and thereafter recommenced. Cell-associated levels of Pel increased rapidly during this period. Cells with elevated levels of Pel released the enzyme when resuspended in buffer or buffer plus sucrose (0.990 a_w); however, little or no Pel was released when the cells were resuspended in buffer plus LiCl, NaCl, KCl, or sorbitol at 0.990 a_w. Release of Pel was accompanied by the release of acid phosphatase (ACP). Pel release was temperature-dependent over the range investigated (15–30 C). Chloroform treatment of cells released Pel and ACP but not β-galactosidase, which indicates that cell-associated Pel is accumulated in the periplasm.