An evolutionary view of the function of CC-type glutaredoxins in plant development and adaptation to the environment.

The article focuses on class III CC-type glutaredoxins (ROXYs), a land plant–specific subgroup of thiol oxidoreductases involved in redox-dependent post-translational modifications critical for plant development, reproduction, and stress responses. ROXYs have diversified into five subgroups (Aα, Aβ, Bα, Bβ, Bγ) in angiosperms, with the Bγ subgroup showing particularly dynamic evolution and specialized roles in nitrogen signaling. Functionally, ROXYs interact with TGA transcription factors and transcriptional co-repressors to modulate gene expression, often acting as negative regulators of biotic and abiotic stress responses, likely by resetting redox-dependent transcriptional changes to maintain plant growth and development. Their biochemical activity involves glutathione-dependent oxidoreductase functions, although substrate specificity and molecular mechanisms vary among ROXY members. The evolutionary expansion and functional diversification of ROXYs suggest their essential role in adapting plants to terrestrial oxidative environments.