Plant Sciences

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

"Depuis plusieurs années, le réseau Sciences des Plantes de Saclay accueillent des groupes scolaires dans des laboratoires de recherche de l’Université Paris Saclay, dans le cadre du programme Des Plantes et des Hommes. Ces visites incitent les adolescents à réfléchir à l’importance des plantes dans l’histoire de l’humanité et au rôle de la génétique dans cette histoire, au passé, mais aussi comme levier de la transition agroécologique actuelle. Elles sont l’occasion pour les élèves de participer à un atelier interactif et de rencontrer des chercheurs en biologie des plantes.

"Understanding plant responses to individual stresses does not mean that we understand real-world situations, where stresses usually combine and interact. These interactions arise at different levels, from stress exposure to the molecular networks of the stress response. Here, we built an in-depth multiomic description of plant responses to mild water (W) and nitrogen (N) limitations, either individually or combined, among 5 genetically different Arabidopsis (Arabidopsis thaliana) accessions. We highlight the different dynamics in stress response through integrative traits such as rosette growth and the physiological status of the plants. We also used transcriptomic and metabolomic profiling during a stage when the plant response was stabilized to determine the wide diversity in stress-induced changes among accessions, highlighting the limited reality of a “universal” stress response. The main effect of the W × N interaction was an attenuation of the N-deficiency syndrome when combined with mild drought, but to a variable extent depending on the accession. Other traits subject to W × N interactions are often accession specific. Multiomic analyses identified a subset of transcript–metabolite clusters that are critical to stress responses but essentially variable according to the genotype factor. Including intraspecific diversity in our descriptions of plant stress response places our findings in perspective."

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

Le réseau Sciences Plantes de Saclay participera une fois encore au Village des Sciences organisé par La Diagonale Paris-Saclay. Nous accueillerons des classes de primaire et de collège le vendredi 4 octobre et le grand-public pourra venir à notre rencontre les samedi 5 et dimanche 6 octobre.

Programme

Programme complet du Village des Sciences Paris-Saclay : https://www.universite-paris-saclay.fr/fete-de-la-science-du-4-au-14-octobre-2024-initiez-vous-a-la-recherche/

Programme complet des activités INRAE (en particulier en Île-de-France) : https://www.inrae.fr/fete-de-la-science

Programme SPS :

Des Plantes et des Hommes
Jouez (quiz, jeu de cartes) et découvrez comment les humains ont utilisé la diversité naturelle pour domestiquer et sélectionner les plantes que nous cultivons aujourd’hui. D’où viennent-elles ? Pourquoi sont-elles adaptées à nos usages ? Seront-elles les mêmes à l’avenir ?
Vendredi 4 octobre (scolaires) / Samedi 5 octobre (grand public) - 14h>18h / Dimanche 6 octobre (grand public) - 11h>18h

Guttation, les perles des feuilles
Dans la nature au petit matin, on peut observer des gouttes d’eau perler sur le bord des feuilles. C’est ce qu’on appelle la guttation, un phénomène facilement confondu avec la rosée.  Qu’est-ce qu’est ? A quoi ça sert ? Quel en est le responsable ? A travers une expérience, percez le mystère de ces « perles » de feuilles !
Vendredi 4 octobre (scolaires) / Samedi 5 octobre (grand public) - 14h>18h / Dimanche 6 octobre (grand public) - 11h>18h

Le bénéfice des fautes d’orthographe pour s’adapter à l’environnement
La diversité génétique inter et intra espèces définit la répartition géographique des plantes dans le monde. Certaines sont capables de s’adapter à des environnements différents, d’autres non. Comment l’expliquer, quelle est la source de cette diversité ? Mimer la synthèse d’un brin d’ADN permettra d’illustrer les mécanismes cellulaires qui génèrent cette diversité et ses conséquences sur la capacité des plantes à s’adapter.
Samedi 5 octobre (grand public) - 14h>18h

Les huiles du bout du monde
Saurez-vous reconnaitre les huiles du bout du monde ? Odeurs, couleurs, textures, origines seront autant d'éléments pour vous guider dans ce voyage dépaysant. Les huiles végétales et leurs fabuleuses propriétés chimiques sont pleines de ressources : alimentation, cosmétique, chimie verte !
Dimanche 6 octobre (grand public) - 11h>18h

La plante face aux changements climatiques
Les plantes sont à la base des chaines trophiques et de l’alimentation humaine. Elles sont adaptées aux conditions climatiques locales et leur répartition géographique est affectée par le changement climatique. Par ailleurs, l’élévation du CO2 atmosphérique booste leur photosynthèse mais cet effet est contrebalancé par la détérioration des conditions de vie. Quelles conséquences pour l’agriculture ?
Vendredi 4 octobre (scolaires)

Localisation

École normale supérieure Paris-Saclay
4, avenue des Sciences
91190 Gif-sur-Yvette
https://ens-paris-saclay.fr/lecole/venir-lecole

http://www.ibpc.fr/UMR7141/en/home/

Diatoms are a major class of phytoplankton, standing at the crossroads of several evolutionary lineages. They represent the most species-rich class of microalgae and are distributed worldwide, from tropical and subtropical regions to polar ecosystems. Thus, the diversity of diatom lifestyles and survival strategies can likely be attributed to their exceptional ability to adapt to diverse environments.

Light is the primary source of energy for photosynthetic organisms but also a key source of information on the surrounding environment. It is well established that diatoms have developed highly effective systems for optimizing light harvesting and energy generation from photosynthesis. Yet, little is known on the role of light sensing in the acclimation mechanisms, which synergistically control diatom cell growth and distribution within the ecological oceanic provinces they inhabit. To address these questions, we are performing integrated analyses of diverse but highly interconnected light-driven processes. By developing genomic and genetic resources for Phaeodactylum tricornutum, currently the most established experimental model for diatom molecular research, and by integrating genome-enabled and (eco)physiology approaches, we started to unveil new molecular players of diatom photoregulation. They include key regulators of photosynthesis and plastid photoprotection, photoreceptor variants, and a long-sought circadian clock controlling diatom responses to periodic light:dark cycles. Comparative functional investigations in diverse species and the analysis of the distribution of light regulators in the marine environment support hypothesis that light-driven processes are key players of diatom persistence. Providing new perspectives on how photoregulators evolved, diversified and act in aquatic environments strongly structured by light, these studies also highlight that integration of laboratory and environmental studies are both timely and essential to understand the life of algae in complex ecosystems.