Scientific Portrait IBMP-CNRS

Institut de Biologie Moléculaire des Plantes (IBMP-CNRS)
Strasbourg University
Scientific portrait

Our research

Plants are outstanding organic chemists and produce extremely diverse repertories of natural metabolites, resulting from the long evolution of terrestrial plant lineages. This very rich chemical equipment provides the building blocks enabling the incredible variability of plant forms during their colonisation of virtually any environment, up to the most extreme. The main objective of our team (E. Gaquerel, https://www.ibmp.cnrs.fr/) is to elucidate the biochemical bases and to trace the evolutionary history of metabolic pathways contributing to the fundamental processes of development, and especially to the adaptation of plants to their biotic and abiotic environment.

Specifically, our team identifies and characterises key genes of plant metabolism and aims to understand the molecular bases, and the evolutionary history of metabolic pathways leading to the synthesis of:

structural biopolymers (phenolic- and fatty acid-based biopolymers)
various specialized metabolites of economic or ecological interest
jasmonate type hormones

Using a wide range of plant models and multidisciplinary approaches (biochemistry, targeted and non-targeted metabolic analyses, molecular genetics, physiology), we seek to acquire fundamental knowledge of plant metabolism at the molecular, enzymatic and supramolecular level as well as on its ecological functions.

Our contribution to KliwiResse

We have studied the jasmonate hormonal pathway for many years and demonstrated in different species its positive effect on tolerance to several stresses, such as microbial attacks or extreme environmental conditions. We have also shown that specific enzymatic modifications of the hormone can change the level of induced resistance. A particular hormonal signature, therefore, allows us to predict signaling activity. This is a precondition to search for regulated targets in plants subjected to either favourable or stressful physiological conditions. As part of KliwiResse, we are going to apply this approach to grapevine and carry out the metabolic characterisation of many varieties (wild and cultivated) provided by the partners JKI and KIT, that differ with respect to their tolerance to drought and heat.

This will be carried out by analysis in liquid or gas chromatography coupled with mass spectrometry, the results will be exploited with a suite of specialised bioinformatics tools. This approach will allow us on the one hand to establish the hormonal profiles (particularly jasmonates) associated with a particular behavior in response to stress, and on the other hand to identify metabolic markers characteristic of tolerance or sensitivity. This new knowledge should facilitate the prediction of stress resilience in new varieties.

What did we achieve

Our contribution
We are studying the response of grapevines to heat stress, looking at the issue from a metabolomic point of view. The idea is that some of the properties of adaptation, or susceptibility, to heat could be based on the particular accumulation of natural compounds ('metabolites'), before or after exposure to stress. We are therefore seeking to identify which metabolites characterize a heat-sensitive variety such as cultivated Riesling or, on the contrary, a heat-tolerant variety such as wild Hördt 29. To this end, we are using leaf samples from plants grown at KIT in summer 2023, derived from a heat stress experiment under controlled conditions including early, intermediate and late measurement points, between these two contrasting vine varieties.

How did we proceed?
We extracted the moderately polar molecules from these numerous leaf samples for metabolomic analysis. The compounds are first separated by liquid or gas chromatography, before being fragmented by mass spectrometry, enabling their detection for relative or absolute quantification, and eventually their identification. These methods enable targeted or global metabolic mapping and, applied to a kinetic study, provide a picture of the comparative evolution of biochemical pathways between different plant varieties.

Our first analysis focused on the hormonal response to heat stress. In a plant, hormones are involved in regulating growth, development and the response to various types of stress, particularly in response to environmental constraints. We then carried out a high-resolution non-targeted analysis, which requires complex bioinformatics processing to obtain their quantification and potential identification. These analyses will help us determine major metabolic differences between Riesling and Hördt 29, some of which may be associated with heat tolerance or sensitivity.

At present, we are carrying out a central metabolic analysis to characterize the evolution under heat conditions of molecules underlying basal processes such as photosynthesis and its carbohydrate production, respiration, nutrient assimilation, and tissue differentiation.

What is the metabolomic response to heat?
Based on a comparison experiment between the wild Hördt 29 vine and the Riesling grape variety, we determined the hormonal profile of various derivatives of jasmonic acid, as well as abscisic acid and salicylic acid, in the face of heat stress. It was observed that the abundance of certain jasmonic acid hormone derivatives was reduced under heat, but with no significant difference between the two types of vine. Contrary to the cold response, the jasmonic acid pathway does not therefore appear to be predominant in the rapid adaptation to high temperatures. The levels of two other stress hormones, abscisic acid and salicylic acid, were little affected by this stress.

Secondly, non-targeted LC-MS exploration identified numerous metabolites belonging to different biochemical classes, which accumulated differently in the two varieties, sometimes already before exposure to heat stress. For example, Hördt 29 is richer in tannin precursors, and Riesling contains more flavonoid derivatives. Other compounds show a particular signature between the two varieties in response to stress. We are working to understand the link between these differences and their significance in terms of heat tolerance. Analysis of the central metabolism will complete our understanding of these differential processes and provide a molecular basis for the results of the physiological measurements carried out by KIT.

Project-relevant publications

Ndecky S, Nguyen TH, Eiche E, Cognat V, Pflieger D, Pawar N, Betting F, Saha S, Champion A, Riemann M, Heitz T. (2023) Jasmonate signaling controls negative and positive effectors of salt stress tolerance in rice. J Exp Bot. doi: 10.1093/jxb/erad086.

Marquis, V., Smirnova, E., Graindorge, S., Delcros, P., Villette, C., Zumsteg, J., Heintz, D. and Heitz, T. (2022). Broad-spectrum stress tolerance conferred by suppressing jasmonate signaling attenuation in Arabidopsis JASMONIC ACID OXIDASE (JAO) mutants. The Plant Journal. 109:856-872. doi:10.1111/tpj.15598.

Marquis V, Smirnova E, Poirier L, Zumsteg J, Schweizer F, Reymond P and Heitz T. (2020) Stress- and pathway-specific impacts of impaired jasmonoyl-isoleucine (JA-Ile) catabolism on defense signalling and biotic stress resistance. Plant Cell Environ 43, 1558-1570. doi: 10.1111/pce.13753.

Heitz T., Smirnova E., Marquis V., and Poirier L. (2019) Metabolic Control within the Jasmonate Biochemical Pathway. Plant Cell Physiol. 60, 2621-2628. doi:10.1093/pcp/pcz172.

Hazman M., Sühnel M., Schäfer S., Zumsteg J., Lesot., Beltran F., Marquis V., Herrgott L., Miesch L., Riemann M. and Heitz T. (2019) Characterization of Jasmonoyl-Isoleucine (JA-Ile) Hormonal Catabolic Pathways in Rice upon Wounding and Salt Stress. Rice (N Y) 12, doi: 10.1186/s12284-019-0303-0.

Team