Protein complexes involved in epigenetic regulation of transcription have 
evolved as molecular strategies to face environmental stress in plants. SAGA 
(Spt-Ada-Gcn5 Acetyltransferase) is a transcriptional co-activator complex that 
regulates numerous cellular processes through the coordination of multiple 
post-translational histone modifications, including acetylation, 
deubiquitination, and chromatin recognition. The diverse functions of the SAGA 
complex involve distinct modules that are highly conserved between yeast, flies, 
and mammals. In this review, the composition of the SAGA complex in plants is 
described and its role in gene expression regulation under stress conditions 
summarized. Some of these proteins are likely involved in the regulation of the 
inducible expression of genes under light, cold, drought, salt, and iron stress, 
although the functions of several of its components remain unknown.