Physiological changes in sorghum antifungal proteins

Changes in sorghum caryopsis antifungal proteins (AFP) in different tissues and during development, imbibition, and germination, were determined. Sormatin, chitinase, and glucanase levels increased during caryopsis development and peaked at physiological maturity (30 days after anthesis (DAA)). Ribosome-inactivating protein levels were higher-at 15 DAA and decreased subsequently. Sormatin and chitinase levels were significantly different between sorghum cultivars. Sormatin content at physiological maturity correlated with mold rating (R(2) = 0.65). Seed AFPs were present in the endosperm and migrated toward the exterior of caryopsis upon imbibition. AFPs leached out of immature seeds but were retained in the pericarp of mature seeds. Levels of these proteins also changed significantly during seed germination and were present in the shoots of germinating caryopsis.