Thesis defence – Université Montpellier

August 31, 2026 at 2:00 p.m. – amphi 206
Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)

Madame Anaïs Rodriguez-Euzet

will publicly defend his thesis entitled

Functional characterization of BOLA proteins in the maintenance of plastidial and mitochondrial activities in Arabidopsis thaliana

Doctoral school : GAIA – Biodiversité, Agriculture, Alimentation, Environnement, Terre, Eau
Spéciality : BIDAP – Biologie, Interactions, Diversité Adaptative des Plantes
University : Université Montpellier
Reasearch unit : IPSiM –  Institut for Plant Sciences of Montpellier

Jury:
Florence VIGNOLS, Chargé de recherche CNRS – Directeur de thèse
Claire REMACLE, Professeur Université de Liège – Rapporteur
Sébastien THOMINE, Directeur de recherche CNRS / Univ. Paris Saclay – Rapporteur
José LE GOURRIEREC-GENTILHOMME, Maître de conférences Université d’Angers – Examinateur
Jean-Philippe REICHHELD, Directeur de recherche CNRS / Univ. Perpignan – Examinateur
Enric ZELAZNY, Chargé de recherche CNRS – IPSiM – Examinateur

Abstract:
In Arabidopsis thaliana, approximately 200 proteins involved in a wide range of metabolic pathways require iron-sulfur (Fe-S) clusters for their activity. These ubiquitous cofactors are essential for fundamental cellular processes, including electron transfer and protein maturation. Despite their importance, many components of the Fe-S cluster assembly and trafficking machinery remain poorly characterized in plants.
This project demonstrates that BOLA1 and BOLA4, two evolutionarily conserved and functionally redundant paralogs localized in plastids and mitochondria, play a crucial role in Fe-S cluster delivery to client proteins. Already known as interactors of monothiol glutaredoxins (GRXs), our work reveals that they also interact with mitochondrial NFU proteins, a family of Fe-S cluster carrier proteins. We show that BOLA1 and BOLA4 are required for the maturation of the 24-kDa, 51-kDa, PSST, and SDH2-1 proteins, corresponding to three Fe-S-containing subunits of mitochondrial respiratory complex I and one subunit of complex II, as well as CNX2, a key enzyme involved in molybdenum cofactor (Moco) biosynthesis.
Consistent with these molecular functions, the bola1 bola4 double mutant displays severe developmental defects accompanied by extensive proteomic alterations. These phenotypes include early arrest of primary root growth, auxin accumulation within the root meristem, early lateral root emergence, increased oxidative stress and disruption of iron homeostasis.
Collectively, our findings establish BOLA1 and BOLA4 as essential and functionally redundant factors required for Fe-S protein maturation, at least in mitochondria, thereby supporting mitochondrial respiration and Moco biosynthesis. Furthermore, these proteins are critical for the maintenance of primary root growth and iron homeostasis. This work identifies BOLA1 and BOLA4 as key components of the Iron-Sulfur Cluster (ISC) machinery responsible for Fe-S cluster trafficking in Arabidopsis.

Keywords: BOLA proteins, Mitochondria/Plastid, Iron-Sulfur Cluster, Fe-S Assembly machineries, Arabidopsis thaliana, Interactomics