Arabidopsis ILITHYIA protein is necessary for proper chloroplast biogenesis and root development independent of eIF2alpha phosphorylation

[EN] One of the main mechanisms blocking translation after stress situations is mediated by phosphorylation of the alpha-subunit of the eukaryotic initiation factor 2 (eIF2), performed in Arabidopsis by the protein kinase GCN2 which interacts and is activated by ILITHYIA(ILA). ILA is involved in pla...

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Bibliographic Details
Authors: Faus, I., Kesari, V., Llabata, P., Tam, E., Nebauer, Sergio G., Santiago, J., Hauser, M.T., Niñoles Rodenes, Regina|||0000-0002-7862-9509, Gadea Vacas, José|||0000-0002-3612-7914
Format: article
Publication Date:2018
Country:España
Institution:Universitat Politècnica de València (UPV)
Repository:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Language:English
OAI Identifier:oai:riunet.upv.es:10251/121382
Online Access:https://riunet.upv.es/handle/10251/121382
Access Level:Open access
Keyword:GCN1
GCN2
Arabidopsis
Transcriptomic
EIF2 alpha
BIOQUIMICA Y BIOLOGIA MOLECULAR
FISIOLOGIA VEGETAL
Description
Summary:[EN] One of the main mechanisms blocking translation after stress situations is mediated by phosphorylation of the alpha-subunit of the eukaryotic initiation factor 2 (eIF2), performed in Arabidopsis by the protein kinase GCN2 which interacts and is activated by ILITHYIA(ILA). ILA is involved in plant immunity and its mutant lines present phenotypes not shared by the gcn2 mutants. The functional link between these two genes remains elusive in plants. In this study, we show that, although both ILA and GCN2 genes are necessary to mediate eIF2 alpha phosphorylation upon treatments with the aromatic amino acid biosynthesis inhibitor glyphosate, their mutants develop distinct root and chloroplast phenotypes. Electron microscopy experiments reveal that ila mutants, but not gcn2, are affected in chloroplast biogenesis, explaining the macroscopic phenotype previously observed for these mutants. ila3 mutants present a complex transcriptional reprogramming affecting defense responses, photosynthesis and protein folding, among others. Double mutant analyses suggest that ILA has a distinct function which is independent of GCN2 and eIF2 alpha phosphorylation. These results suggest that these two genes may have common but also distinct functions in Arabidopsis.