GETTING OUT OF THE SHADE: CHARACTERIZATION OF NOVEL BHLH/HLH THAT MODULATE SHADE AVOIDANCE RESPONSES

MARCELO YANOVSKY; CARLOS ESTEBAN HERNANDO; LUCILA VALESE; SANTIAGO MORA GARCIA

Paraná

Congreso; LIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2018

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Plants grown at high crop densities receive reduced light irradiance as a result of mutual shading. Some plants have developed the ability to avoidshade by readjusting phenotypical traits such as growth rates of the stems, internodes and petioles, among others. Taken together, these responsesare known as Shade Avoidance Syndrome (SAS). Whereas these responses may be useful in nature to improve photosynthesis, in agronomicalpractices they are detrimental because resources that should be used for the filling of the harvested organs are diverted to sustain elongation. Atthe molecular level, many of these responses are mediated by a family of typical and atypical basic helix loop helix transcription factors, bHLHsand HLH respectively. These transcription factors orchestrate a complex signaling network were some bHLH/HLHs act as activators of the SASwhile others act as a brake of the responses. Using a high throughput transcriptome analysis of shaded Glycine max(Soybean) plants, we found anovel bHLH/HLH that could modulate SAS responses in this legume of agronomic interest. Using a reverse genetics approach, we set to studythe role of the orthologs of this gene in Arabidopsis thaliana in the regulation of the shade avoidance response. Our findings suggest that onlysubsets of these orthologues are involved in the shade responses. This work contributes to the characterization of novel bHLH/HLHs thatparticipate in the intricate signaling network of shade avoidance responses.