RESISTANCE TO ASPERGILLUS-FLAVUS IN CORN KERNELS IS ASSOCIATED WITH A14-KDA PROTEIN

Corn genotypes resistant or susceptible to Aspergillus flavus were ext racted for protein analysis using a pH 2.8 buffer. The profile of prot ein extracts revealed that a 14-kDa protein is present in relatively h igh concentration in kernels of seven resistant corn genotypes, but is absent or present only in low concentration in kernels of six suscept ible ones. The N-terminal sequence of this 14-kDa protein showed 100% homology to a corn trypsin inhibitor. The 14-kDa protein purified from resistant varieties also demonstrated in vitro inhibition of both try psin activity and the growth of A. flavus. This is the first demonstra tion of antifungal activity of a corn 14-kDa trypsin inhibitor protein . The expression of this protein among tested genotypes may be related to their difference in resistance to A. flavus infection and subseque nt aflatoxin contamination.