FUNCTIONAL CHARACTERIZATION OF GZF1 DURING BRANCHED INFLORESCENCE DEVELOPMENT

BELLINO CAROLINA D.;; REINHEIMER R.

Congreso; RAFV Conference; 2021

The grass family is characterized by their inflorescence architecture, which final form is the result of a balance between the ability of the axillary meristems to form branches or terminate in spikelets. GRASS ZINC FINGER 1 (GZF1) is a Cys2-His2-type zinc finger transcription factor that seems to influence the fate of axillary meristems at early stages of inflorescence development. The aim of this work is to explore the molecular and functional divergence of GZF1 grass homologs. By comparison of C2H2 zinc finger peptide sequences available on databases, we observed a partial conservation of the sequences towards the C-terminal. As a result of phylogenetic analysis, we identified two successive duplications of GZF1 at the grass family origin which generated three unique grass sequences lineages. In order to generate knowledge on GZF1 expression patterns and its biological role, we performed experiments with GZF1 homologs of three PACMAD species (Zea mays, Setaria viridis and Cenchrus echinatus). Expression experiments showed that GZF1 homologs are preferentially expressed in inflorescence with developing branches and their expression decays at late stages of inflorescence development. Transgenic Arabidopsis thaliana plants that overexpress GZF1 homologs showed a highly branched phenotype in comparison with wild type plants. We observed the presence of sterile branches similar to bristles of the Setaria inflorescence. These results suggest that homologs of GZF1 may regulate the fate of apical and axillary meristems in transgenic Arabidopsis plants.