AAO3 — Arabidopsis thaliana

Summary

AT2G27150 (AAO3) in Arabidopsis thaliana encodes an abscisic aldehyde oxidase, a molybdenum cofactor-containing enzyme with FAD and 2Fe-2S binding domains that catalyses the final step of abscisic acid (ABA) biosynthesis. AAO3 is associated with ABA metabolism and signalling, and mutants show drought tolerance, reduced ABA levels, wilty leaves, altered stomatal movement and closure, and changes in seed dormancy and germination. The gene is associated with chlorophyll breakdown, leaf senescence, hormone anabolism including gibberellin and cytokinin, TOR signalling, and responses to water, salt, temperature and oxidative stress. AAO3 has also been linked to callus formation, memory, cutin biosynthesis, and resistance to Bamboo mosaic virus and Pythium irregulare. The protein localises to plastids, cytosol and nucleus. Studies of related genes in other species link the family to seed shattering, root architecture, plant height, fruit traits, and abiotic stress tolerance.