Resumen de Identification of key regulatory genes involved in arsenic perception in Arabidopsis thaliana
Arsenic is a toxic metalloid naturally present in the biosphere. Agricultural soils and drinking waters are under threat of toxic metalloid contamination due to natural weathering processes —further exacerbated by climate change—, posing a significant risk to humans. This serious situation has sparked interest in the design of novel sustainable strategies to deal with arsenic contamination. In this sense, understanding how plants sense and tolerate arsenic would be of outmost importance for phytoremediation applications, as well as for the generation of crops that limit the accumulation of the metalloid in edible plants, enabling safe agriculture in contaminated areas. In recent years, we have gained understanding of the mechanisms of arsenic uptake and detoxification in plants. However, the components of arsenic signaling triggering the arsenic response in plants remain to be discovered. Arsenic tolerance comprises a compendium of responses that include uptake restriction, sequestering and extrusion of the metalloid. In response to arsenic, a number of genes and biological pathways exhibit transcriptional regulation, indicating the existence of an arsenic-specific signaling pathway and suggesting that transcriptional regulation is a major factor in the arsenic response in plants. In this thesis, we aimed at the identification of transcriptional regulators of the arsenic response in Arabidopsis thaliana by means of a high-throughput Y1H, using as baits arsenic responsive promoters in combination with an in silico analysis of binding sites of gene clusters derived from an RNA-seq of roots exposed to the metalloid. Among all the selected transcription factors , we focused on PLETHORA3/5/7 and GLABRA2 as central regulators of arsenic detoxification mechanisms in tight coordination with the modulation root development under arsenic stress. In this work we have made a significant contribution to the identification and characterization of master regulators involved in arsenic sensing in Arabidopsis and we provide the first insights into how plants effectively adapt their root shape and growth and recover from the arsenic stress
