Identification of chemical components of corn kernel pericarp wax associated with resistance to Aspergillus flavus infection and aflatoxin production.

Kernel pericarp wax of the corn breeding population GT-MAS:gk has been associated with resistance to Aspergillus flavus infection and aflatoxin production. GT-MAS:gk wax, previously compared to waxes of three susceptible genotypes, was presently compared to wax of a different, and more numerous, group of susceptible lines. Wax separation by TLC confirmed previous findings, demonstrating a unique GT-MAS:gk band and a unique "susceptible" band. Only GT-MAS:gk wax inhibited the growth of A. flavus; however, no association was established, as before, between kernel wax abundance and resistance. Gas chromatography-mass spectroscopy (GC-MS) analysis of kernel whole wax showed a higher percentage of phenol-like compounds in wax from GT-MAS:gk than in waxes from the susceptible lines. The GT-MAS:gk unique band contained phenol-like compounds and ethyl-hexadecanoate; butyl-hexadecanoate was preeminent in most of the "susceptible bands". Alkylresorcinol (phenolic compounds) content was dramatically higher in GT-MAS:gk wax than in the wax of susceptible lines. An alkylresorcinol, 5-methylresorcinol, also inhibited in vitro growth of A. flavus. These and other phenolic compounds may contribute to kernel wax inhibition of A. flavus infection/aflatoxin production. Further investigation is needed to confirm a role for them in GT-MAS:gk resistance.

[1]  N. W. Widstrom,et al.  Registration of GT-MAS: gk Maize Germplasm , 1993 .

[2]  K. Kramer,et al.  Properties of Barley Seed Chitinases and Release of Embryo-Associated Isoforms during Early Stages of Imbibition. , 1992, Plant physiology.

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

[4]  T. Cleveland,et al.  Living Maize Embryo Influences Accumulation of Aflatoxin in Maize Kernels. , 1993, Journal of food protection.

[5]  G. E. Scott,et al.  Registration of Mp420 Germplasm Line of Maize , 1992 .

[6]  G. E. Scott,et al.  Sources of Resistance in Maize to Kernel Infection by Aspergillus flavus in the Field , 1988 .

[7]  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 .

[8]  T. Cleveland,et al.  Comparison of Kernel Wax from Corn Genotypes Resistant or Susceptible to Aspergillus flavus. , 1997, Phytopathology.

[9]  A. Sakurai,et al.  Isolation of 5-(8′Z-heptadecenyl)-resorcinol from etiolated rice seedlings as an antifungal agent , 1996 .

[10]  D. Bhatnagar,et al.  Molecular Strategies for Reducing Aflatoxin Levels in Crops before Harvest , 1992 .

[11]  J. P. Blakeman,et al.  SEASONAL OCCURRENCE OF AN ANTIMICROBIAL FLAVANONE, SAKURANETIN, ASSOCIATED WITH GLANDS ON LEAVES OF RIBES NIGRUM , 1982 .

[12]  T. D. Wyllie,et al.  Mycotoxic Fungi, Mycotoxins, Mycotoxicoses. An Encyclopedic Handbook , 1979 .

[13]  G. Payne,et al.  Growth of an Aspergillus flavus transformant expressing Escherichia coli beta-glucuronidase in maize kernels resistant to aflatoxin production. , 1997, Journal of food protection.

[14]  N. W. Widstrom,et al.  Segregation for Resistance to Aflatoxin Contamination among Seeds on an Ear of Hybrid Maize , 1987 .

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

[16]  T. Cleveland,et al.  Wax and Cutin Layers in Maize Kernels Associated with Resistance to Aflatoxin Production by Aspergillus flavus. , 1995, Journal of food protection.

[17]  T. Cleveland,et al.  Reduction in Aflatoxin Content of Maize by Atoxigenic Strains of Aspergillus flavus. , 1991, Journal of food protection.

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

[19]  H. Gottlieb,et al.  5-(12-heptadecenyl)-resorcinol, the major component of the antifungal activity in the peel of mango fruit , 1986 .