Insight into diversification and evolution of HD-Zip I transcription factors in Streptophytes

ROMANI F; CHAN RL; MORENO JE

Cordoba

Congreso; SAIB 2016; 2016

SAIB

Streptophytes dispersion and evolution onto land was accompanied by an increment in the number of genes encoding transcription factors (TFs). This rise in TFs diversity suggests that they might have played a fundamental role in the adaptation of plants to an environment with less water availability. Homeodomain-leucine zipper I (HD-Zip I) is a TF family whose members are involved in drought responses. In Arabidopsis, this family has 17 members and based on mutant phenotypes it is proposed they redundant functions. Until now, HD-Zip I were identified only in the land plant lineage. Here, we report the identification of HD-Zip I genes in aquatic charophytes genomes. We also found a single common ancestor in land plants. Duplication events occurring in specific plant divisions might explain the emergence of current clades of HD-Zip I in angiosperms, likely due to neofunctionalization. We also identified a couple of HD-Zip I gene-loss events related to monocot plants that have moved back to aquatic environment. To better understand the diversification and evolution of HD-Zip I TFs, we are now using the livewort Marchantia polymorpha, which occupies a basal position in the evolution of land plants. Marchantia genome also has a low genetic redundancy in regulatory genes and encodes a unique HD-Zip I that could be relevant to understand the role of these genes during the transition to land.