Biology subjects

Chervin, C.

Publications and source records attributed to Chervin, C..

5 recordsLinked to original sources

bioRxiv2025

Manipulation of in planta ethylene levels modulates the metabolome of Populus tremula x tremuloides in a microbial-dependent manner.

BackgroundThe assembly of tree microbiota is a dynamic process that varies across space and time, influenced by both biotic and abiotic factors. Plants have developed defence strategies, mediated by phytohormones such as ethylene, to manage its interactions with pathogens and, in certain non-perennials, interactions with the commensal microbiota. However, whether and how ethylene regulation affects the assembly of tree microbiota is unknown. ResultsWe investigated the assembly of fungal and bacterial communities in poplars (P. tremula x. P. tremuloides T89), altered either in ethylene biosynthesis (ACO1), or in ethylene perception (etr1.1), by combining high-throughput amplicon sequencing with confocal microscopy. In parallel, we characterised root exudates, as well as root and shoot metabolomes of the different poplar lines grown on sterile soil and in the presence of microbiota using GC-MS. Alteration of ethylene levels had little impact on the metabolome of sterile poplars, but led to differential primary and secondary metabolic responses in the root and shoots of poplars colonised by microorganisms. These metabolomic changes were associated with a decrease in fungal colonisation of shoots, particularly by saprophytes in the early stages, whereas reduced ethylene stimulated root colonisation by fungi. Conversely, arbuscular mycorrhizal fungal and bacterial communities, as well as root exudation, were little affected by changes in ethylene production. ConclusionThe findings of this study suggest a potential dual role for ethylene in poplar, whereby its levels may either promote or inhibit microbial growth and activity, depending on the concentration, microbial trophic guild, and poplar organ.

plant biology↗

bioRxiv2024

Responses of grapevine cells to physiological doses of ethanol, among which induced resistance to heat stress

Grapevine naturally endures stresses like heat, drought, and hypoxia. A recent study showed very low oxygen levels inside grape berries, linked to ethanol content. Other studies have established the link between ethanol and tolerance to various stresses: heat stress, drought, and high salinity. The causes of such a tolerance are not well understood. In our study, three-week-old Gamay calli, Vitis vinifera, were characterised for their endogenous oxygen levels and endogenous ethanol concentration. Subsequently, a transcriptomic study of these cells was conducted, 6 and 24 hours after treatment with 1 mM ethanol. After 6 hours, ethanol addition led to 386 differentially expressed genes, with a notable upregulation of genes related to heat response, especially small Heat Shock Proteins (sHSPs). Further experiments showed that ethanol priming in grape cells or in Arabidopsis seedlings reduced pigment and electrolyte leakage under heat stress, respectively. This study supports the idea that ethanol priming helps protect plants against heat stress and provides a valuable RNA-seq dataset for further research into the underlying mechanisms, sHSPs playing a potentially crucial role in this adaptive response.

plant biology↗

bioRxiv2024

Ethanol reduces grapevine water consumption by limiting transpiration

Studies suggest that ethanol (EtOH), triggers plant adaptation to various stresses at low concentrations (10 {micro}M to 10 mM). This study investigates whether EtOH induces drought acclimation in grapevine, as demonstrated previously in Arabidopsis, rice, and wheat. Preliminary results with bare root Gamay cuttings showed that those pre-treated with 10 {micro}M EtOH aqueous solutions lost fewer leaves when deprived of water compared to controls. Subsequently, we ran a potted-cutting experiment with progressive soil water deficit. Plants pre-treated with 250 mM EtOH solutions exhibited slower depletion of the fraction of transpirable soil water (FTSW), compared to controls. While 250 mM EtOH decreased transpiration in early days, these EtOH pre-treated plants maintained higher leaf transpiration than controls after 10 days of soil water depletion. The transpiration response to FTSW was affected by EtOH application. EtOH pre-treatments limited plant leaf expansion without increasing leaf senescence. Interestingly, plants primed with EtOH followed typical hormesis curves. These results suggest that EtOH improves grapevine acclimation to drought, leading to potential water-savings in wine growing regions prone to high water shortages, linked to climate change. These should encourage further testing under various vineyard conditions.

plant biology↗

bioRxiv2022

Ethylene impact on grapevine pistil temperature and fruit set

Ethylene is known to stimulate plant respiration, and this later is always associated with heat generation. The grapevine fruit set is dependent upon pistil temperature, controlling the pollen germination and ovule fertilization. This led us to test whether ethylene would be able to impact fruit set often limited in cool climate conditions, particularly in the case of Vitis vinifera L. cv. Malbec, a variety prone to poor fruit set. With this cultivar, we ran trials in growth chambers using the ethylene gas, and field trials using ethephon as an ethylene precursor. At 14.5 {degrees}C ambient temperature, we observed that ethylene at 1 and 10 ppm increased the stigma and pistil temperature to 15 {degrees}C, compared to 14.7 {degrees}C in controls. This minor temperature rise was associated with an increase of fruit set from 10 to 25 %. The field trials, conducted in the South West of France, confirmed this trend. Indeed, spraying a concentration as low as 216 mg/ha of ethephon onto Malbec at full bloom at 16 {degrees}C in the shade, led to an increase of fruit set from 35 % to 45 %. These experiments suggest that spraying ultra-low concentrations of ethylene precursors onto the grapevines prone to poor fruit set, during cool mornings, could improve fruit set and reduce crop losses.

plant biology↗

bioRxiv2020

Phytohormone production by the arbuscular mycorrhizal fungus Rhizophagus irregularis

Arbuscular mycorrhizal symbiosis is a mutualistic interaction between most land plants and fungi of the glomeromycotina subphylum. The initiation, development and regulation of this symbiosis involve numerous signalling events between and within the symbiotic partners. Among other signals, phytohormones are known to play important roles at various stages of the interaction. During presymbiotic steps, plant roots exude strigolactones which stimulate the fungus, and favour the initiation of symbiosis. At later stages, different plant hormone classes can act as positive or negative regulators of the interaction. Although the fungus is known to reciprocally emit regulatory signals, its potential contribution to the phytohormonal pool has received little attention, and has so far only been addressed by indirect assays. In this study, using mass spectrometry, we analyzed phytohormones released into the medium by germinated spores of the arbuscular mycorrhizal fungus Rhizophagus irregularis. We detected the presence of a cytokinin (isopentenyl-adenosine) and an auxin (indole-acetic acid). In addition, we identified a gibberellin (gibberellic acid 4) in spore extracts. We also used gas chromatography to show that R. irregularis produces ethylene from methionine and the -keto {gamma}-methylthiobutyric acid pathway. These results highlight the possibility for AM fungi to use phytohormones to interact with their host plants, or to regulate their own development.

plant biology↗