Evolution of the Cytokinin Dehydrogenase (CKX) Domain.

Siarhei A Dabravolski, Stanislav V Isayenkov

Journal of molecular evolution 2021 Dec

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Plant hormone cytokinins are important regulators of plant development, response to environmental stresses and interplay with other plant hormones. Cytokinin dehydrogenases (CKXs) are proteins responsible for the irreversible break-down of cytokinins to the adenine and aldehyde. Even though plant CKXs have been extensively studied, homologous proteins from other taxa remain mainly uncharacterised. Here we present our study on the molecular evolution and divergence of the CKX from bacteria, fungi, amoeba and viridiplantae. Although CKXs are present in eukaryotes and prokaryotes, they are missing in algae and metazoan taxa. The prevalent domain architecture consists of the FAD-binding and cytokinin binding domains, whereas some bacteria appear to have only cytokinin binding domain proteins. The CKXs play important role in the various aspects of plant life including control of plant development, response to biotic and abiotic stress, influence nutrition. Results of our study suggested that CKX originates from the FAD-linked C-terminal oxidase and has a defence-oriented function. The obtained results significantly extend the current understanding of the cytokinin dehydrogenases structure-function from the relationship to homologues from other taxa and provide a starting point baseline for their future functional characterization. © 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Citation

Siarhei A Dabravolski, Stanislav V Isayenkov. Evolution of the Cytokinin Dehydrogenase (CKX) Domain. Journal of molecular evolution. 2021 Dec;89(9-10):665-677