Submitted to: American Peanut Research and Education Society Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2003
Publication Date: March 1, 2004
Citation: Liang, X.Q., Guo, B., Holbrook, Jr., C.C., Lynch, R.E. 2004. Resistance to aspergillus flavus in peanut seeds is associated with constitutive trypsin inhibitor and inducible chitinase and B-1-3-glucanase [abstract]. Proceedings of the American Peanut Research and Education Society, July 8-11, 2003, Clearwater, Florida. 35:85. Technical Abstract: Peanut is one of the most susceptible crops to Aspergillus flavus invasion and aflatoxin production. The objectives of this research were to study the constitutive expressed protein trypsin inhibitor and inducible antifungal hydrolase chitinase and ß-1-3-glucanase by Aspergillus infection, which may associate with the resistance in peanut seeds. The purified trypsin inhibitor (TI) in peanut seeds, including two subunits with molecular weight of 10.3-kD and 17-kD, respectively, can inhibit Aspergillus spore germination and growth in vitro in the concentration of 10ug.ml-1. The concentration and activity of TI in resistant genotypes were significantly higher than that in susceptible genotypes. The activities of chitinase and ß-1-3-glucanase were increased significantly in the seeds after inoculation with A. flavus. The enzymatic activity was considerably higher in the resistance genotypes at 3-4d after inoculation than that in susceptible genotypes. From in-gel (native PAGE) assay, one band and two bands of endo-chitinase isoforms were detected in susceptible and resistant genotypes, respectively. The isoform patterns of ß-1-3-glucanase also showed more bands in resistant genotypes than in susceptible genotypes. Chitinase from PI337494 inoculated with A. flavus was purified with molecular weight 31-kD. The purified chitinase from peanut significantly inhibits spores germination and hypha growth in vitro.