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 asso ciated with resistance to Aspergillus flavus infection and aflatoxin produc tion. GT-MAS:gk wax, previously compared to waxes of three susceptible geno types, was presently compared to wax of A different, and more numerous, gro up of susceptible lines. Wax separation by TLC confirmed previous findings, demonstrating a unique GT-MAS:gk band and a unique "susceptible" band. Onl y GT-MAS:gk wax inhibited the growth of A. flavus; however, no association was established, as before, between kernel wax abundance and resistance. Ga s chromatography-mass spectroscopy (GC-MS) analysis of kernel whole wax sho wed 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 p henol-like compounds and ethyl-hexadecanoate; butyl-hexadecanoate was preem inent in most of the "susceptible bands". Alkylresorcinol (phenolic compoun ds) content was dramatically higher in GT-MAS:gk wax than in the wax of sus ceptible lines. An alkylresorcinol, 5-methylresorcinol, also inhibited in v itro growth of A. flavus. These and other phenolic compounds may contribute to kernel wax inhibition of A. flavus infection/aflatoxin production. Furt her investigation is needed to confirm a role for them in. GT-MAS:gk resist ance.