Plant Sciences

Après avoir été cheffe du département scientifique Biologie et amélioration des plantes de 2020 à 2024, Isabelle Litrico est désormais directrice scientifique Agriculture d’INRAE. Une fonction qu’elle embrasse avec conviction et goût grâce à un parcours conséquent à l’interface de nombreuses disciplines, en relation avec de nombreux partenaires.

Symbiosis evolution is often viewed as a progress, with emergence of new adaptive properties. However, symbiosis also enhances the interdependence between partners. I describe several such interdependences, and emphasize that they arise without emergence of new property. Generally, when two partners permanently interact, a mutation in one partner can be complemented by the other. Independency is then lost without any positive selection, in a neutral evolution. The accumulation of such steps makes the reversion to independency unlikely, and drives interdependency in symbiosis. 

Thiol-dependent redox regulation of enzyme activities plays a central role in regulating photosynthesis. Besides the regulation of metabolic pathways, alternative electron transport is subjected to thiol-dependent regulation. We investigated the regulation of O2 reduction at photosystem I. The level of O2reduction in leaves and isolated thylakoid membranes depends on the photoperiod in which plants are grown. We used a set of Arabidopsis (Arabidopsis thaliana) mutant plants affected in the stromal, membrane, and lumenal thiol network to study the redox protein partners involved in regulating O2 reduction. Light-dependent O2 reduction was determined in leaves and thylakoids of plants grown in short-day and long-day conditions using a spin-trapping electron paramagnetic resonance assay. In wild-type samples from short-day conditions, reactive oxygen species generation was double that of samples from long-day conditions, while this difference was abolished in several redoxin mutants. An in vitro reconstitution assay showed that thioredoxin m, NADPH-thioredoxin reductase C, and NADPH are required for high O2-reduction levels in thylakoids from plants grown in long-day conditions. Using isolated photosystem I, we also showed that reduction of a photosystem I protein is responsible for the increase in O2 reduction. Furthermore, differences in the membrane localization of m-type thioredoxins and 2-Cys peroxiredoxin were detected between thylakoids of short-day and long-day plants. Overall, we propose a model of redox regulation of O2reduction according to the reduction power of the stroma and the ability of different thiol-containing proteins to form a network of redox interactions.

We are pleased to announce that the "PLant science in the ANThropocene" (PLANT) workshop will take place March 24th to April 4th 2025 at University Paris-Saclay. It will address key challenges from basic sciences to socio-economic and environmental aspects including climate change. Applications for researchers (postdoc level and above) to participate have opened today, see
https://eng-saclay-plant-sciences.hub.inrae.fr/events/workshop-institut-pascal
The deadline for applying is December 17th.

The "PLant science in the ANThropocene" (PLANT) workshop will run from March 24 to April 4, 2025 at the Institut Pascal of the University Paris-Saclay (campus about 25 km south of Paris).

This 2-week workshop will address key challenges for the international Plant Science community, from basic sciences to socio-economic and environmental aspects including climate change. It will gather about 60 international scientists. The attendance will mix high stature senior scientists, together with numerous younger ones.

The program will focus on three themes:
- Theme I: "Frontiers in Plant Science fundamental research" (March 24-25-26)
- Theme II: “Feeding the planet: roles for Plant Science and associated socio-economic challenges" (March 27-28-31 and April 1)
- Theme III: "Plants as factories: from chemical compounds to mitigating climate change” (April 2-3-4)

Mornings will consist mainly of presentations by about 20 senior scientists, who will provide their vision of how to rise to those challenges, while the afternoon sessions will be devoted principally to brainstorming across generations on selected topics. This workshop will thus require input from all participants, the goals being the emergence of consensus community opinions and the specification of paths to success for several major challenges, be they at the level of training the next generation, guiding deciders of public policies, or connecting with the wider public on the importance of plant sciences in the Anthropocene. All these challenges are of high complexity and depend on several disciplines. Thus, beyond plant biologists and geneticists, some participants will come from agronomy, ecology, social and environmental sciences, economics, and also from chemical, physical and computational sciences.

Syntheses in the form of opinion papers will be drafted for publication.

APPLICATIONS ARE OPEN FOR PARTICIPATION IN THIS WORKSHOP

Applications deadline: Tuesday December 17, midnight

To know more and apply : https://indico.ijclab.in2p3.fr/event/10763/

Admission is restricted because of capacity constraints and the need to have the brainstorming sessions be effective. There are no registration fees and lunches and coffee breaks will be provided.

Participants must hold a PhD

Innate immune receptors provide plants with sufficient recognition specificities to maintain resistance against rapidly evolving pathogens. Understanding the rules of plant innate receptor evolution can produce new bioengineering approaches to genetic resistance in crops. Availability of plant pan-genomes, including those of Arabidopsis, Brachypodium, soybean and maize, allowed us to identify subsets of receptors that are highly variable in nature. With updated computational approaches, we are able to predict and rationally modify receptor ligand binding sites. Newly engineered receptors require appropriate control of receptor activation, which we are achieving through a combination of protein engineering and transcriptional regulation. We foresee application of synthetic biology combined with genome editing to become a sustainable solution to disease resistance and can be adapted across different crops.

In recent years, the exploration of genome three-dimensional (3D) conformation has yielded profound insights into the regulation of gene expression and cellular functions in both animals and plants. While animals exhibit a characteristic genome topology defined by topologically associating domains (TADs), plants display similar features with a more diverse conformation across species. Employing advanced high-throughput sequencing and microscopy techniques, we investigated the landscape of 26 histone modifications and RNA polymerase II distribution in tomato (Solanum lycopersicum). Our study unveiled a rich and nuanced epigenetic landscape, shedding light on distinct chromatin states associated with heterochromatin formation and gene silencing. Moreover, we elucidated the intricate interplay between these chromatin states and the overall topology of the genome. Employing a genetic approach, we delved into the role of the histone modification H3K9ac in genome topology. Notably, our investigation revealed that the ectopic deposition of this chromatin mark triggered a reorganization of the 3D chromatin structure, defining different TAD-like borders. Our work emphasizes the critical role of H3K9ac in shaping the topology of the tomato genome, providing valuable insights into the epigenetic landscape of this agriculturally significant crop species.

https://www.tsl.ac.uk/about/people/sophien-kamoun

Plants coordinately use cell-surface and intracellular immune receptors to perceive pathogens and mount an immune response. Intracellular events of pathogen recognition are largely mediated by immune receptors of the nucleotide binding and leucine rich-repeat (NLR) classes. Upon pathogen perception, NLRs trigger a potent broad-spectrum immune reaction, usually accompanied by a form of programmed cell death termed the hypersensitive response. Some plant NLRs act as multifunctional singleton receptors which combine pathogen detection and immune signaling. However, NLRs can also function in higher order pairs and networks of functionally specialized interconnected receptors. I will cover the basic aspects of plant NLR biology with an emphasis on NLR networks. I will highlight some of the recent advances in NLR structure, function, and activation and discuss emerging topics such as modulator NLRs, pathogen suppression of NLRs, and NLR bioengineering. Multi-disciplinary approaches are required to disentangle how these NLR immune receptor pairs and networks function and evolve. Answering these questions holds the potential to deepen our understanding of the plant immune system and unlock a new era of disease resistance breeding.

Contreras, M.P., Luedke, D., Pai, H., Toghani, A., and Kamoun, S. 2023. NLR receptors in plant immunity: making sense of the alphabet soup
https://www.embopress.org/doi/full/10.15252/embr.202357495

Very nice talk of Sophien Kamoun (@KamounLab),  about Plant Immunity for the students of the Master of Plant Sciences...

L’équipe pédagogique du Master Professionnel, « Innovation en Qualité et Productions Végétales » vous invite à LA JOURNEE DES METIERS IQPV, le vendredi 4 octobre 2024, Amphi, Bâtiment 630, IPS2, avec le soutien de SPS

This Summer School is organized by the Saclay Plant Sciences (SPS) network, one of the largest European plant sciences communities, and will be hosted by the cytology and imaging platform of the Institut Jean Pierre Bourgin - Plant Sciences in Versailles.

Microscopy is a fundamental tool for understanding the functioning of plants at the cellular to molecular scale. Recent technological advances (super-resolution, fluorescence lifetime imaging, biosensors...) now make it possible to address new scientific questions. This Summer School will provide theoretical and practical insights into these aspects for 20 outstanding and enthusiastic PhD students or young postdoctoral researchers divided in small groups. Participants will have the opportunity to discuss the advantages and disadvantages of different modalities, sample preparation, image acquisition, and data processing throughout the week.

 

The Summer School will include:

> A set of theoretical lectures (~9 hours) on the major issues in advanced imaging. The lectures will be given by experts in the field, who will be available for discussions during the Summer School, giving the participants an insight into the latest research findings and identifying key open questions in the field.

> A set of practical sessions (~24 hours + Restitution) to tackle real-life approaches on plant samples and compare different modalities of conventional confocal microscopy, super-resolution and fluorescence lifetime analysis. All Summer School participants will have access to all practical sessions, in groups of 3 or 4, with one (or more) expert per system. Given the advanced technologies covered, the Summer School is aimed at PhD students or young post-docs who already have practical experience in confocal microscopy. At the end of the Summer School, the experiences of all participants will be confronted in a general discussion, to expose the differences and possible advantages of the imaging technologies approached.

> Participant flash-talks and poster session (5 hours)

> Social activities

 

This intensive and varied one-week program will allow many opportunities to discuss with speakers and fellow participants.

 

Deadline for application: March 4, 2025 (midnight)

Dear colleague,

The International Master 1 'Plant and Microbial molecular Biology', entirely taught in English, has opened at the beginning of the academic year 2023, in the framework of the "Saclay Plant Sciences" (SPS) network.

This Master 1, intended primarily for international students, aims to train, through research, future specialists in the most recent concepts of biology at a molecular level, applied to the current challenges of research on plants and micro-organisms.

This training is part of new pedagogical practices called "active" which favours the dynamic participation of students, an immersion in the laboratories as well as individual tutoring to develop the autonomy of students in project management.

We would be grateful if you could circulate this announcement and the attached flyer within your structure and international networks.

All details are available on the WEBSITE.

Marianne Delarue and Matthieu Jules
Coordinators of the Master PMB

C-terminally encoded peptides (CEPs) are small secreted signaling peptides that promote nitrogen-fixing root nodulation symbiosis in legumes depending on soil mineral nitrogen availability. In the Medicago truncatula model legume plant, their action is mediated by the leucine-rich repeat receptor-like protein kinase COMPACT ROOT ARCHITECTURE 2 (CRA2). Like most land plants, under inorganic phosphate limitation, M. truncatula establishes another root endosymbiotic interaction with arbuscular fungi, the arbuscular mycorrhizal symbiosis (AMS). Because this interaction is beneficial for the plant but has a high energetic cost, it is tightly controlled by host plants to limit fungal infections mainly depending on phosphate availability. In a study published in Current Biology by the F. Frugier team at IPS2, in collaboration with Nicolas Frey-dit-Frei at the LRSV (Toulouse), we showed that the expression of a subset of CEP-encoding genes is enhanced in the low-phosphate conditions. In addition, overexpression of one of these low-phosphate-induced CEP gene, MtCEP1, previously shown to promote the nitrogen-fixing root nodulation symbiosis, enhances AMS from the initial entry point of the fungi. Conversely, a loss-of-function mutation of the CRA2 receptor required for mediating CEP peptide action decreases the endomycorrhizal interaction from the same initial fungal entry stage. Transcriptomic analyses revealed that the cra2 mutant is negatively affected in the regulation of key phosphate transport and response genes as well as in the biosynthesis of strigolactone hormones that are required for establishing AMS. Accordingly, strigolactone contents were drastically decreased in cra2 mutant roots. Overall, we showed that the CEP/CRA2 pathway promotes both root nodulation and AMS in legume plants, depending on soil mineral nutrient availability.

Contact: florian.frugier@universite-paris-saclay.fr

#IJPB  We are happy to announce that Léa Barreda from SEEDEV team : http://bit.ly/3rlXeZN will defend her PhD When? Thurday 31th October at 2 pm to register and join us http://bit.ly/4f3LZvc