A Tomato Tocopherol Binding Protein Sheds Light on Intracellular α-tocopherol Metabolism in Plants

Luisa Bermúdez , Talía del Pozo , Bruno Silvestre Lira , Fabiana de Godoy , Irene Boos , Cecilia Romanò , Viola Previtali , Juliana Almeida , Claire Bréhélin (1) , Ramón Asis , Leandro Quadrana , Diego Demarco , Saleh Alseekh , Rigel Salinas Gamboa , Laura Pérez-Flores , Pia Guadalupe Dominguez , Christophe Rothan (2) , Alisdair Robert Fernie , Maurício González , Achim Stocker , Andreas Hemmerle , Mads Hartving Clausen , Fernando Carrari , Magdalena Rossi

1 LBM - Laboratoire de biogenèse membranaire
2 INRA - Institut National de la Recherche Agronomique

Tocopherols are non-polar compounds synthesized in the plastids, which function as major antioxidants of the plant cells and are essential in the human diet. Both the inter-mediates and final products of the tocopherol biosynthetic pathway must cross plastid membranes to reach their sites of action. So far, no protein with tocopherol binding activity has been reported in plants. Here, we demonstrated that the tomato SlTBP protein is targeted to chloroplasts and able to bind a-tocopherol. SlTBP-knockdown tomato plants exhibited reduced levels of tocopherol in both leaves and fruits. Several tocopherol deficiency phenotypes were apparent in the transgenic lines, such as alterations in photosyn-thetic parameters, dramatic distortion of thylakoid membranes and significant variations in the lipid profile. These results, along with the altered expression of genes related to photosynthesis, and tetrapyrrole, lipid, isopre-noid, inositol/phosphoinositide and redox metabolism, suggest that SlTBP may act in conducting tocopherol (or its biosynthetic intermediates) between the plastid compartments and/or at the interface between chloroplast and endoplasmic reticulum membranes, affecting interorganel-lar lipid metabolism.

Mots clés: lipid metabolism; Solanum lycopersicum; tocopherol metabolism; tomato

Mots clés: organelle communication

Domaines: Biologie végétale

Luisa Bermúdez, Talía del Pozo, Bruno Silvestre Lira, Fabiana de Godoy, Irene Boos, et al.. A Tomato Tocopherol Binding Protein Sheds Light on Intracellular α-tocopherol Metabolism in Plants. Plant and Cell Physiology, 2018, 59 (11), pp.2188-2203. ⟨10.1093/pcp/pcy191⟩. ⟨hal-02106324⟩