Plant Biology Researcher M/F

Job Description

Missions

The agent will be responsible for elucidating the functional role and mechanisms of action of LMTP1 and TLP26 proteins in the biogenesis, maintenance, and regulation of photosystem II (PSII) in Chlamydomonas reinhardtii. Their main tasks will consist of:

- Identifying the interaction partners of LMTP1 and TLP26 within PSII and other photosynthetic complexes.
- Understanding the molecular mechanism by which these proteins influence photosynthetic performance.
- Establishing a link between the observed “stay green” phenotype and redox or retrograde signaling processes.
- Developing and characterizing genetic mutants to validate hypotheses in vivo.

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Activity

A. Identification of interaction partners

- Isolate thylakoid membranes from C. reinhardtii cultures (normal conditions and light stress).
- Perform salt treatments to expose the Mn complex of PSII.
- Apply cross-linkers in the presence of recombinant CrLMTP1 and CrTLP26 proteins.
- Collaborate with external partners to identify, by mass spectrometry, the contact points between the proteins of interest and the photosynthetic subunits.
- Use proximity labeling techniques (e.g., TurboID) to map the interactome of target proteins.

B. Functional and mechanistic characterization

- Design and produce mutated variants of the TPM domains of LMTP1 and TLP26 (directed mutagenesis at key sites: conserved cysteines, metal binding site, etc.).
- Perform in vitro/in vivo pull-down assays to validate the identified interactions.
- Measure oxygen evolution, chlorophyll a fluorescence, and QA-QB electron transfer under different conditions.
- Use metal-sensitive dyes (e.g., BODIPY) to track Mn compartmentalization in the thylakoid lumen.

C. Generation and phenotyping of mutants

- Generate point mutants of C. reinhardtii by CRISPR/Cas9 at sites identified as critical.
- Design constructs for in vivo labeling (fluorescent tags, TurboID) to track localization.

Your Profil

Skills

Technical skills (know-how) - Advanced mastery of molecular biology techniques: cloning, site-directed mutagenesis, PCR, Western blot. - Proven experience in protein biochemistry: recombinant protein production, purification, pull-down assays, chemical cross-linking. - In-depth knowledge of spectroscopy methods and photosynthetic activity measurement: chlorophyll fluorescence, O₂ evolution, redox titrations. - Proficiency in reverse genetics tools (CRISPR/Cas9) and Chlamydomonas reinhardtii transformation. - Experience in confocal microscopy and image analysis for tracking labeled proteins. - Ability to use omics data analysis software (mass spectrometry, interactome). Theoretical knowledge - Excellent understanding of photosynthesis, PSII structure and function, and the mechanisms of photosynthetic complex biogenesis and repair. - Knowledge of retrograde signaling pathways and redox processes in chloroplasts.
Familiarity with microalgae physiology and responses to environmental stress. Interpersonal skills - Independence and rigor in planning and conducting complex experiments. - Ability to work in a team and collaborate with academic and technical partners. - Analytical and synthesis skills to interpret multifaceted results and propose mechanistic hypotheses. - Good written and oral communication skills (report writing, scientific presentations, exchanges with colleagues).

Your Work Environment

As part of the Photosynthesis & Environment (P&E) team at BIAM (Biosciences and Biotechnologies of Aix-Marseille), a CEA laboratory located on the Cadarache campus, you will join a multidisciplinary team dedicated to studying the fundamental mechanisms of photosynthesis, from the molecular scale to plant physiology. Our team is committed to deciphering the factors that determine photosynthetic performance in plants and microalgae, in particular their ability to acclimatize to fluctuations in light and CO₂, in the context of climate change. We combine innovative approaches in genetics, biochemistry, biophysics, and modeling to elucidate the fine regulations of solar energy capture, electron transfer, CO₂ fixation, and the resilience of photosynthetic organisms. The project is part of a dynamic scientific environment, benefiting from privileged access to cutting-edge technological platforms (Imaplant, Phytotec) and non-invasive phenotyping tools developed for real-time monitoring of photosynthetic processes. You will work at the heart of a collaborative ecosystem, interacting with experts in structural biology, ecophysiology, synthetic biology, and systemic modeling, and will benefit from a network of academic and industrial collaborations, both nationally and internationally.
The P&E team, led by Jean Alric and Xenie Johnson, is recognized for its excellence in studying the structure-function relationships of photosynthetic complexes, as well as for its translational approaches aimed at optimizing crop and microalgae productivity in the face of abiotic stresses. Your work will contribute directly to major societal challenges, such as the adaptation of photosynthetic organisms to environmental constraints and the development of sustainable solutions for agriculture and low-carbon energy production. You will benefit from a stimulating work environment, combining fundamental research and practical applications, within an institute committed to energy and ecological transition.
The Aix Marseille Institute of Biosciences and Biotechnology (BIAM) is a Joint Research Unit (UMR) comprising around 100 permanent employees and 50 non-permanent employees (fixed-term contracts, doctoral and post-doctoral students, interns). The UMR is located on the CEA Cadarache site and on the Luminy Faculty of Sciences campus. BIAM's fundamental research projects aim to understand the mechanisms involved in the response and adaptation of living organisms to environmental constraints and to develop technologies dedicated to preserving the quality of our environment. They are conducted using several multidisciplinary approaches on model organisms (algae, plants, bacteria) or on the most adapted organisms based on biodiversity studies.

Compensation and benefits

Compensation

4000 to 4200 gross

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions