PHYSIOLOGICAL-CHANGES IN SORGHUM ANTIFUNGAL PROTEINS

Changes in sorghum caryopsis antifungal proteins (AFP) in different ti ssues and during development, imbibition, and germination, were determ ined. Sormatin, chitinase, and glucanase levels increased during caryo psis development and peaked at physiological maturity (30 days after a nthesis (DAA)). Ribosome-inactivating protein levels were higher-at 15 DAA and decreased subsequently. Sormatin and chitinase levels were si gnificantly different between sorghum cultivars. Sormatin content at p hysiological 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 wer e retained in the pericarp of mature seeds. Levels of these proteins a lso changed significantly during seed germination and were present in the shoots of germinating caryopsis.