Purification and characterization of 1,3-β-glucan hydrolases from healthy and Verticillium albo-atrum-infected tomato plants

• Published in: Physiological plant pathology Vol. 19; no. 3; pp. 391 - 417
• Main Authors: Young, D.H., Pegg, G.F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.1981
• Subjects: fungal diseases of plants; plant biochemistry; plant health; plant pathogenic fungi; plant physiology
• ISSN: 0048-4059
• DOI: 10.1016/S0048-4059(81)80072-0

Three endo-l,3-β-glucanases with similar properties were purified from leaves and stems of tomato plants. Exo-l,3-β-glucanase and a β-glucosidase, active on 1,3-β-glucans, were purified from Verticillium albo-atrum culture filtrate. No evidence was found for endo-l,3-β-glucanase production by V. albo-atrum. 1,3-β-Glucan hydrolases were characterized in terms of substrate specificity, kinetic constants, molecular weight, pH- and temperature-activity relationships, isoelectric point and susceptibility to inhibitors. Increased 1,3-β-glucanase activity in stem tissue following infection of tomato by V. albo-atrum resulted from increased levels of constitutive host 1,3-β-glucanases present in healthy tissue. Activity in crude extracts from healthy and infected stem was due primarily to endo-1,3-β-glucanases, and showed the same response to pH and temperature and the same pattern on isoelectricfocusing. Most of the 1,3-β-glucanase from infected stem behaved like the enzyme from healthy stem during purification. Quantitative precipitin assay of 1,3-β-glucanase activity in crude extracts from infected stem demonstrated that almost all 1,3-β-glucanase was immunologically identical to a purified preparation from healthy tissue.