Inhibition of plant-pathogenic fungi by a corn trypsin inhibitor overexpressed in Escherichia coli

• Published in: Applied and Environmental Microbiology Vol. 65; no. 3; pp. 1320 - 1324
• Main Authors: Chen, Z.Y, Brown, R.L, Lax, A.R, Cleveland, T.E, Russin, J.S
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01-03-1999
• Subjects: alpha-Amylases - antagonists & inhibitors; antifungal properties; Aspergillus flavus; Aspergillus flavus - drug effects; Aspergillus flavus - growth & development; Aspergillus parasiticus; Bacteria; Biological and medical sciences; Biological control; Coculture Techniques; Control; Enzyme Inhibitors - isolation & purification; Enzyme Inhibitors - metabolism; Enzyme Inhibitors - pharmacology; Enzymes; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Fungi; Fusarium - drug effects; Fusarium - growth & development; Fusarium moniliforme; Microbial Sensitivity Tests; Microbiology; Phytopathology. Animal pests. Plant and forest protection; Plant Microbiology; Plant Proteins - genetics; Plant Proteins - isolation & purification; Plant Proteins - metabolism; Plant Proteins - pharmacology; Recombinant Proteins - pharmacology; spore germination; Trypsin - metabolism; Trypsin Inhibitors; Zea mays; Zea mays - chemistry; Zea mays - genetics; Recombinant microorganism; Microorganism growth; Serine endopeptidases; Plant pathogen; Enzyme; Escherichia coli; Germination; Biological control; Enzyme inhibitor; Corn; Gene overexpression; Fungi; Peptidases; Trypsin; Bacteria; Hydrolases; Inhibition; Recombinant protein; Enterobacteriaceae; Thallophyta
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/aem.65.3.1320-1324.1999

The cDNA of a 14-kDa trypsin inhibitor (TI) from corn was subcloned into an Escherichia coli overexpression vector. The overexpressed TI was purified based on its insolubility in urea and then refolded into the active form in vitro. This recombinant TI inhibited both germination and hyphal growth of all nine plant pathogenic fungi studied, including Aspergillus flavus, Aspergillus parasiticus, and Fusarium moniliforme. The calculated 50% inhibitory concentration of TI for conidium germination ranged from 70 to more than 300 microgram/ml, and that for fungal growth ranged from 33 to 124 micrograms/ml depending on the fungal species. It also inhibited A. flavus and F. moniliforme simultaneously when they were tested together. The results suggest that the corn 14-kDa TI may function in host resistance against a variety of fungal pathogens of crops.