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.
Gembeh
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SV
Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture (USDA-ARS), New Orleans, Louisiana 70179, USA.
Brown
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Grimm
C
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Cleveland
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TE
D000348:Aflatoxins / Q000096:biosynthesis*; D001231:Aspergillus flavus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D008401:Gas Chromatography-Mass Spectrometry; D005838:Genotype; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology*; D018514:Plant Structures / Q000737:chemistry*; D012118:Resorcinols / Q000032:analysis / Q000494:pharmacology; D014885:Waxes / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D003313:Zea mays / Q000737:chemistry* / Q000235:genetics / Q000382:microbiology
D000348:Aflatoxins; D012118:Resorcinols; D014885:Waxes; C005282:orcinol