A Corn Trypsin Inhibitor with Antifungal Activity Inhibits Aspergillus flavus alpha-Amylase.

ABSTRACT In this study, we found that the inhibition of fungal growth in potato dextrose broth (PDB) medium by the 14-kDa corn trypsin inhibitor (TI) protein, previously found to be associated with host resistance to aflatoxin production and active against various fungi, was relieved when exogenous alpha-amylase was added along with TI. No inhibitory effect of TI on fungal growth was observed when Aspergillus flavus was grown on a medium containing either 5% glucose or 1% gelatin as a carbon source. Further investigation found that TI not only inhibited fungal production of extracellular alpha-amylase when A. flavus was grown in PDB medium containing TI at 100 mug ml(-1) but also reduced the enzymatic activity of A. flavus alpha-amylase by 27%. At a higher concentration, however, TI stimulated the production of alpha-amylase. The effect of TI on the production of amyloglucosidase, another enzyme involved in starch metabolism by the fungus, was quite different. It stimulated the production of this enzyme during the first 10 h at all concentrations studied. These studies suggest that the resistance of certain corn genotypes to A. flavus infection may be partially due to the ability of TI to reduce the production of extracellular fungal alpha-amylase and its activity, thereby limiting the availability of simple sugars for fungal growth. However, further investigation of the relationship between TI levels and fungal alpha-amylase expression in vivo is needed.

[1]  T. Cleveland,et al.  Inhibition of Plant-Pathogenic Fungi by a Corn Trypsin Inhibitor Overexpressed in Escherichia coli , 1999, Applied and Environmental Microbiology.

[2]  T. Cleveland,et al.  Advances in the Development of Host Resistance in Corn to Aflatoxin Contamination by Aspergillus flavus. , 1999, Phytopathology.

[3]  J. Widholm,et al.  β-l,3-Glucanase and Resistance to Aspergillus flavus Infection in Maize , 1998 .

[4]  T. Cleveland,et al.  Resistance to Aspergillus flavus in Corn Kernels Is Associated with a 14-kDa Protein. , 1998, Phytopathology.

[5]  M. D. Waard.  Significance of ABC transporters in fungicide sensitivity and resistance. , 1997 .

[6]  T. Cleveland,et al.  Inducers of Aflatoxin Biosynthesis from Colonized Maize Kernels Are Generated by an Amylase Activity from Aspergillus flavus. , 1997, Phytopathology.

[7]  T. Cleveland,et al.  Resistance to aflatoxin contamination in corn as influenced by relative humidity and kernel germination. , 1996, Journal of food protection.

[8]  A. Chagolla-López,et al.  FURTHER CHARACTERIZATION OF THE 12 kDa PROTEASE/ALPHA AMYLASE INHIBITOR PRESENT IN MAIZE SEEDS , 1995 .

[9]  K. W. Campbell,et al.  Determination of resistance to aflatoxin production in maize kernels and detection of fungal colonization using an Aspergillus flavus transformant expressing Escherichia coli β-glucuronidase. , 1995 .

[10]  A. Chandrashekar,et al.  Antifungal proteins from sorghum endosperm and their effects on fungal mycelium , 1994 .

[11]  Franky R. G. Terras,et al.  Synergistic Enhancement of the Antifungal Activity of Wheat and Barley Thionins by Radish and Oilseed Rape 2S Albumins and by Barley Trypsin Inhibitors , 1993, Plant physiology.

[12]  G. Reeck,et al.  α-amylases from three species of stored grain coleoptera and their inhibition by wheat and corn proteinaceous inhibitors☆ , 1992 .

[13]  J. Zobel,et al.  Isolation and characterization of a 22 kDa protein with antifungal properties from maize seeds. , 1992, Biochemical and biophysical research communications.

[14]  W. K. Roberts,et al.  Zeamatin, an antifungal protein from maize with membrane-permeabilizing activity , 1990 .

[15]  D. Hough,et al.  Purification and characterization of glucose dehydrogenase from the thermoacidophilic archaebacterium Thermoplasma acidophilum. , 1989, The Biochemical journal.

[16]  P. Cotty,et al.  Virulence and cultural characteristics of two Aspergillus flavus strains pathogenic on cotton. , 1989 .

[17]  W. K. Roberts,et al.  Antifungal Proteins from Plants a , 1988, Annals of the New York Academy of Sciences.

[18]  T. Boller,et al.  Antifungal Hydrolases in Pea Tissue : I. Purification and Characterization of Two Chitinases and Two beta-1,3-Glucanases Differentially Regulated during Development and in Response to Fungal Infection. , 1988, Plant physiology.

[19]  D. Boulter,et al.  A novel mechanism of insect resistance engineered into tobacco , 1987, Nature.

[20]  A. Blanco-Labra,et al.  A possible function for thaumatin and a TMV-induced protein suggested by homology to a maize inhibitor , 1987, Nature.

[21]  T. N. Pattabiraman,et al.  Isolation and characterization of an amylase inhibitor from sorghum seeds, specific for human enzymes , 1986 .

[22]  W. K. Roberts,et al.  Isolation and partial characterization of two antifungal proteins from barley. , 1986, Biochimica et biophysica acta.

[23]  S. Duffey,et al.  Plant proteinase inhibitors: Mechanism of action and effect on the growth and digestive physiology of larval Heliothis zea and Spodoptera exiqua , 1986 .

[24]  A. Blanco-Labra,et al.  PURIFICATION AND CHARACTERIZATION OF AN α‐AMYLASE INHIBITOR FROM MAISE (ZEA MAIZE) , 1981 .

[25]  T. N. Pattabiraman,et al.  Natural plant enzyme inhibitors. Characterization of an unusual alpha-amylase/trypsin inhibitor from ragi (Eleusine coracana Geartn.). , 1981, The Biochemical journal.

[26]  J J Pisano,et al.  Hageman factor fragment inhibitor in corn seeds: purification and characterization. , 1980, Thrombosis research.

[27]  J. Gatehouse,et al.  Biochemical basis of insect resistance in Vigna unguiculata , 1979 .

[28]  G. Reeck,et al.  Isolation and characterization of trypsin inhibitor from opaque-2 corn seeds. , 1977, The Journal of biological chemistry.

[29]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[30]  J. Adye,et al.  INCORPORATION OF LABELLED COMPOUNDS INTO AFLATOXINS. , 1964, Biochimica et biophysica acta.

[31]  M. De.  Multidrug resistance in Aspergillus nidulans involves novel ATP-binding cassette transporters , 2022 .