Séminaire INTERNE

3 Présentations des étudiants de 2^ème année

Jeudi 25 janvier 2024

Amphi 2 Bât. 2Bis à 14h00

Jiang Duo

Supervisor: Boris PARENT (Team MAGE LEPSE)

Genetic variability in the floret fertility of wheat in response to various heat scenarios with physiological and modelling approaches

With global warming, there’s an increased likelihood of recurrent high temperatures events during crucial development stages for wheat. The knowledge of interactions between multiple heat stresses impacts on floret fertility still remain scarce. Due to wheat’s unique developmental characteristics, there are position-specific and unsynchronized floret developments within a plant, which leads to varying and dynamic physiological responses of a floret to heat stress both spatially and temporarily. Genetic variability in heat sensitivities and development gradients, making the interactions even more intricate. The project aims to study wheat floret fertility’s response to varying heat scenarios, factoring in genetic variability. The overall goal is to develop a quantitatively characterized ecophysiological methodologies and models for evaluating and predicting the integrated response of floret fertility to a single or multiple short-time heat stresses.

Anaïs Rodriguez

Supervisor: Florence Vignols (Feros, IPSiM)

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

Iron-sulfur (Fe-S) clusters are universal cofactors embedded in proteins in which they promote electron transfer, catalytic activities and protein folding. Proteins carrying such cofactors (called Fe-S proteins or client apoproteins) are very diverse in nature due to the chemical diversity of Fe-S centers. They participate in a wide range of biological functions including photosynthesis and respiration. The scaffolding of Fe-S centers and their delivery to client proteins are ensured by three subcellular machineries (SUF, ISC and CIA) involving numerous proteins and cofactors. Despite the importance of these machineries for life, many questions remain about the exact function of some of their components and the mechanisms governing the recognition of client proteins by Fe-S center delivery proteins. These questions are particularly relevant for plants, in which the client apoproteins are 10 times more numerous than the Fe-S shuttle proteins acting within Fe-S assembly machineries.

My thesis project focuses on the physiological and molecular study of two paralogs in Arabidopsis thaliana, BOLA1 and BOLA4, suspected to act as cofactors in the plastidial and mitochondrial SUF and ISC assembly machineries, respectively. BOLAs are highly conserved in prokaryotes and eukaryotes, and capable of forming heterodimers in planta with class-II glutaredoxins (GRXS) involved in the late stages of SUF and ISC machineries. However, no physiological role has been assigned to BOLA proteins, alone or associated with GRXS, and their mode of action remains to be identified in plants. Our recent work shows that the cumulative loss of function of AtBOLA1 and AtBOLA4 genes induces a very marked dwarf phenotype and a profound alteration of root architecture, indicating a very important role of BOLA1 and BOLA4 in plant growth and development. Proteome analysis of bola1bola4 also shows a strong decrease or even total loss of many Fe-S center proteins in the mitochondria and chloroplast, as well as a disturbance of iron distribution in the plant. Finally, the bola1bola4 double mutation causes an alteration of other protein complexes essential to the plastid, without any apparent link with iron nutrition. Therefore, my current work aims to confirm the involvement of BOLA1 and BOLA4, alone or in partnership with GRXS, in the transfer of Fe-S centers to client apoproteins by interactomics approaches. They also aim at identifying other molecular components of root development and iron transport and uptake targeted by the action of BOLA proteins, by physiological, molecular and imaging approaches, for a better understanding of the different roles and modes of action of BOLA proteins.

Martha Violet

Supervisors: Anne Pellegrino, Benoît Pallas (LEPSE)

Analysis  and characterisation of functioning and growth of grapevine resistant  varieties in response to contrasted cover crop and management practices

This  study is dedicated to the analysis of the nutritional (C,N) and water  functioning of grapevine subjected to contrasted genotype x environment x management interactions in order to define new  multi-factorial ‘ideotypes’ in the context of climate change and loss of  biodiversity.

Three  grapevine varieties known to be resistant to fungal diseases will be  studied and their environment will be modified with different inter-row covering and irrigation practices.
The  impact of training systems will be analysed using plants subjected to  contrasted crop load conditions, foliage height and pruning practices (including minimal pruning). The measurements will involve  medium to high throughput phenotyping methods (near infra-red  spectometrie, leaf fluorescence). This approach will allow accessing  some precise measurement at the organ scale on water (transpiration), nitrogen, carbon (photosynthesis) and to investigate the carbohydrate  composition of vegetative and reproductive organs, at the whole plant  level.

A  special focus will be given to the impact of management practices/  training systems on carbon and nitrogen allocation between vegetative and reproductive parts in order to determine the best  equilibrium between water and nitrogen consumption, yield and sugar  accumulation in berries. Finally, a functional structural modelling  approach will be used to simulate in-silico the performance of the different systems at the plant or  vineyard scale in term of light interception, water and nitrogen use  and carbon production. This will help defining the relative importance of the different measured parameters (architectural/functional) on the  water and nitrogen use-efficiency of the system.
Contact : sandra.cortijo@cnrs.f

Jeudi 1^er février : François BARBIER – Equipe Honude (contact francois.barbier@cnrs.fr)
Jeudi 22 février : Rob Roelfsema (contact : doantrung.luu@cnrs.fr )
Jeudi 29 février : Séminaire doctorants 1^er année (contact : sandra.cortijo@cnrs.fr)

https://www1.montpellier.inra.fr/wp-inra/bpmp/actualites/ rubrique Séminaires (2020-2025)

Contacts IBIP :
Sabine Zimmermann (sabine.zimmermann@cnrs.fr)
Justine Drouault (justine.drouault@inrae.fr)
Jessica Bertheloot (jessica.bertheloot@inrae.fr)
Chantal Baracco (chantal.baracco@inrae.fr)