Polygalacturonase‐inhibiting protein accumulates in Phaseolus vulgaris L. in response to wounding, elicitors and fungal infection

• Published in: The Plant journal : for cell and molecular biology Vol. 5; no. 5; pp. 625 - 634
• Main Authors: Bergmann, Carl W., Ito, Yuki, Singer, Darrell, Albersheim, Peter, Darvill, Alan G., Benhamou, Nicole, Nuss, Laurence, Salvi, Giovanni, Cervone, Felice, Lorenzo, Giulia
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.05.1994; Blackwell Science
• Subjects: Agronomy. Soil science and plant productions; Amino Acid Sequence; Antibody Specificity; Biological and medical sciences; Colletotrichum lindemuthianum; Fabaceae - metabolism; Fabaceae - microbiology; Fabaceae - ultrastructure; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Microscopy, Electron; Mitosporic Fungi - ultrastructure; Molecular Sequence Data; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Phaseolus vulgaris; Phytopathology. Animal pests. Plant and forest protection; Plant Diseases; Plant Proteins - biosynthesis; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Medicinal; RNA, Messenger - biosynthesis; Salicylates - pharmacology; Salicylic Acid; Salicylic acid; Plant pathogen; Enzyme; Immunocytochemistry; Injury; Polygalacturonase; Elicitor; Fungi; Proteins; Grain legume; Leguminosae; Phaseolus vulgaris; Dicotyledones; Glycosidases; Angiospermae; Colletotrichum lindemuthianum; Hydrolases; Defense mechanism; Spermatophyta; Fungi Imperfecti; Inhibition; O-Glycosidases; Thallophyta
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.1994.00625.x

Summary Polygalacturonase‐inhibiting protein (PGIP) is a cell wall‐associated protein that specifically binds to and inhibits the activity of fungal endopolygalacturonases. The Phaseolus vulgaris gene encoding PGIP has been cloned and characterized. Using a fragment of the cloned pgip gene as a probe in Northern blot experiments, it is demonstrated that the pgip mRNA accumulates in suspension‐cultured bean cells following addition of elicitor‐active oligogalacturonides or fungal glucan to the medium. Rabbit polyclonal antibodies specific for PGIP were generated against a synthetic peptide designed from the N‐terminal region of PGIP; the antigenicity of the peptide was enhanced by coupling to KLH. Using the antibodies and the cloned pgip gene fragment as probes in Western and Northern blot experiments, respectively, it is shown that the levels of PGIP and its mRNA are increased in P. vulgaris hypocotyls in response to wounding or treatment with salicylic acid. Using gold‐labeled goat‐anti‐rabbit secondary antibodies in EM studies, it has also been demonstrated that, in bean hypocotyls infected with Colletotrichum lindemuthianum, the level of PGIP preferentially increases in those cells immediately surrounding the infection site. The data support the hypothesis that synthesis of PGIP constitutes an active defense mechanism of plants that is elicited by signal molecules known to induce plant defense genes.