The Histone Acetyltransferase GCN5 and Transcriptional Coactivator ADA2b Affect Trichome Initiation in <i>Arabidopsis thaliana</i>

While genome sequencing projects have helped us uncover what information is encoded in DNA of many species, one critical challenge that remains is to understand how gene function is controlled. We investigate the roles of chromatin‐modifying factors in regulating developmental processes in Arabidopsis thaliana . Our current work explores how the histone acetyltransferase GCN5 and the associated transcriptional adaptor ADA2b act to define which leaf cells are selected to become trichomes, single‐celled protrusions implicated in defense mechanisms. In a loss‐of‐function ada2b mutant background, trichome number on rosette leaves is decreased while in gcn5 mutant backgrounds the number of trichomes tends to increase. Using qRT‐PCR analysis, we have established a role for GCN5 in impacting the expression of key players in the trichome initiation pathway including the paralogs Repressor of GA (RGA) and GA Insensitive (GAI) . Gibberellic acid (GA) signaling stimulates trichome initiation by blocking the DELLA repressors RGA and GAI, which in turn block a transcription factor cascade that controls trichome development. This approach has the potential to identify novel connections between GA, a critical plant hormone, and histone acetylation in plant growth. It also provides an example of how chromatin modifiers and transcription factors interact to drive developmental processes. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .