Les séminaires ont lieu sur le Campus Montpellier Institut Agro/INRA de La Gaillarde (2, place P. Viala Montpellier)

Jeudi 28 septembre 2023

à 14h – Amphi 208 (Coeur d’école)

Santosh B. Satbhai

Assistant Professor & DBT Ramalingaswami Fellow (Indian Institute of Science Education and Research, India)

HY5: A Pivotal Regulator of Iron Deficiency Signaling in Plants

Iron (Fe) is an essential micronutrient for both plants and animals. Fe limitation significantly reduces crop yield and therefore has adverse impacts on human nutrition. Owing to limited bio-availability of Fe, plants have adapted different strategies that regulate Fe uptake and homeostasis. Particularly, modifications of root growth traits are a key for the survival of plants on Fe-deficient soils. Understanding molecular basis for these root growth responses will have critical implications for plant breeding. Fe uptake is regulated by the basic helix-loop-helix (bHLH) transcription factors and it is highly induced under iron deficiency. In our study, we find that HY5 (Elongated Hypocotyl 5), a member of the basic leucine zipper (bZIP) family of transcription factors plays an important role in iron deficiency signalling pathway in Arabidopsis thaliana. The hy5 mutant plants fails to mount an iron deficiency response and has less iron and chlorophyll content than WT under iron limitation. Further studies showed that the genes involved in iron uptake which include FER-like iron deficiency-induced transcription factor (FIT), Ferric Reduction Oxidase 2 (FRO2) and Iron-Regulated Transporter1 (IRT1) are less induced in the mutant as compared to the WT under iron deficiency. Interestingly, our results also showed that HY5 acts as a negative regulator of BRUTUS (BTS) which is known to negatively regulate iron deficiency responses. Chromatin Immunoprecipitation followed by qPCR reveals direct binding of HY5 to the promoter of BTS. Altogether, our results show that HY5 plays an important role in activation of iron deficiency responses in Arabidopsis.

Contact : Christian Dubos

Contacts IBIP :

Sabine Zimmermann (sabine.zimmermann@cnrs.fr)

Alexandre Martiniere (alexandre.martiniere@cnrs.fr)

Aude Coupel-Ledru (aude.coupel-ledru@inrae.fr)

Chantal Baracco (chantal.baracco@inrae.fr)