eSoil: A low-power bioelectronic growth scaffold that enhances crop seedling growth

Active hydroponic substrates that stimulate on demand the plant growth have not been demonstrated so far. Here, we developed the eSoil, a low- power bioelectronic growth scaffold that can provide electrical stimulation to the plants’ root system and growth environment in hydroponics settings. eSoil’s active material is an organic mixed ionic electronic conductor while its main structural component is cellulose, the most abundant biopolymer. We demonstrate that barley seedlings that are widely used for fodder grow within the eSoil with the root system integrated within its porous matrix. Simply by polarizing the eSoil, seedling growth is accelerated resulting in increase of dry weight on average by 50% after 15 d of growth. The effect is evident both on root and shoot development and occurs during the growth period after the stimulation. The stimulated plants reduce and assimilate NO3− more efficiently than controls, a finding that may have implications on minimizing fertilizer use. However, more studies are required to provide a mechanistic understanding of the physical and biological processes involved. eSoil opens the pathway for the development of active hydroponic scaffolds that may increase crop yield in a sustainable manner

An ectomycorrhizal fungus alters sensitivity to jasmonate, salicylate, gibberellin, and ethylene in host roots.

The phytohormones jasmonate, gibberellin, salicylate, and ethylene regulate an interconnected reprogramming network integrating root development with plant responses against microbes. The establishment of mutualistic ectomycorrhizal symbiosis requires the suppression of plant defense responses against fungi as well as the modification of root architecture and cortical cell wall properties. Here, we investigated the contribution of phytohormones and their crosstalk to the ontogenesis of ectomycorrhizae (ECM) between grey poplar (Populus tremula x alba) roots and the fungus Laccaria bicolor. To obtain the hormonal blueprint of developing ECM, we quantified the concentrations of jasmonates, gibberellins, and salicylate via liquid chromatography-tandem mass spectrometry. Subsequently, we assessed root architecture, mycorrhizal morphology, and gene expression levels (RNA sequencing) in phytohormone-treated poplar lateral roots in the presence or absence of L. bicolor. Salicylic acid accumulated in mid-stage ECM. Exogenous phytohormone treatment affected the fungal colonization rate and/or frequency of Hartig net formation. Colonized lateral roots displayed diminished responsiveness to jasmonate but regulated some genes, implicated in defense and cell wall remodelling, that were specifically differentially expressed after jasmonate treatment. Responses to salicylate, gibberellin, and ethylene were enhanced in ECM. The dynamics of phytohormone accumulation and response suggest that jasmonate, gibberellin, salicylate, and ethylene signalling play multifaceted roles in poplar L. bicolor ectomycorrhizal development

Biohybrid plants with electronic roots via in vivo polymerization of conjugated oligomers

Plant processes, ranging from photosynthesis through production of biomaterials to environmental sensing and adaptation, can be used in technology via integration of functional materials and devices. Previously, plants with integrated organic electronic devices and circuits distributed in their vascular tissue and organs have been demonstrated. To circumvent biological barriers, and thereby access the internal tissue, plant cuttings were used, which resulted in biohybrids with limited lifetime and use. Here, we report intact plants with electronic functionality that continue to grow and develop enabling plant-biohybrid systems that fully maintain their biological processes. The biocatalytic machinery of the plant cell wall was leveraged to seamlessly integrate conductors with mixed ionic-electronic conductivity along the root system of the plants. Cell wall peroxidases catalyzed ETE-S polymerization while the plant tissue served as the template, organizing the polymer in a favorable manner. The conductivity of the resulting p(ETE-S) roots reached the order of 10 S cm(-1) and remained stable over the course of 4 weeks while the roots continued to grow. The p(ETE-S) roots were used to build supercapacitors that outperform previous plant-biohybrid charge storage demonstrations. Plants were not affected by the electronic functionalization but adapted to this new hybrid state by developing a more complex root system. Biohybrid plants with electronic roots pave the way for autonomous systems with potential applications in energy, sensing and robotics

The mutualism effector MiSSP7 of Laccaria bicolor alters the interactions between the poplar JAZ6 protein and its associated proteins

Despite the pivotal role of jasmonic acid in the outcome of plant-microorganism interactions, JA-signaling components in roots of perennial trees like western balsam poplar (Populus trichocarpa) are poorly characterized. Here we decipher the poplar-root JA-perception complex centered on PtJAZ6, a co-repressor of JA-signaling targeted by the effector protein MiSSP7 from the ectomycorrhizal basidiomycete Laccaria bicolor during symbiotic development. Through protein–protein interaction studies in yeast we determined the poplar root proteins interacting with PtJAZ6. Moreover, we assessed via yeast triple-hybrid how the mutualistic effector MiSSP7 reshapes the association between PtJAZ6 and its partner proteins. In the absence of the symbiotic effector, PtJAZ6 interacts with the transcription factors PtMYC2s and PtJAM1.1. In addition, PtJAZ6 interacts with it-self and with other Populus JAZ proteins. Finally, MiSSP7 strengthens the binding of PtJAZ6 to PtMYC2.1 and antagonizes PtJAZ6 homo-/heterodimerization. We conclude that a symbiotic effector secreted by a mutualistic fungus may promote the symbiotic interaction through altered dynamics of a JA-signaling-associated protein–protein interaction network, maintaining the repression of PtMYC2.1-regulated genes

Chitosan-Modified Polyethyleneimine Nanoparticles for Enhancing the Carboxylation Reaction and Plants' CO2 Uptake

Increasing plants' photosynthetic efficienc y is a major challenge that must be addressed in order to cover the food demands of the growing population in the changing climate. Photosynthes i s is greatly limited at the initial carboxylation reaction, where CO2 is converted to the organic acid 3-PGA, catalyzed by the RuBisCO enzyme. RuBisCO has poor affinity for CO2, but also the CO2 concentration at the RuBisCO site is limited by the diffusion of atmospheric CO2 through the various leaf compartments to the reaction site. Beyond genetic engineer-ing, nanotechnology can offer a materials-based approach for enhancing photosynthesis, and yet, it has mostly been explored for the light-dependent reactions. In this work, we developed polyethyleneimine-based nanoparticl e s for enhancing the carbox-ylation reaction. We demonstrate that the nanoparticles can capture CO2 in the form of bicarbonate and increase the CO2 that reacts with the RuBisCO enzyme, enhancing the 3-PGA production in in vitro assays by 20%. The nanoparticles can be introduced to the plant via leaf infiltration and, because of the functionalization with chitosan oligomers, they do not induce any toxic effect to the plant. In the leaves, the nanoparticles localize in the apoplastic space but also spontaneously reach the chloroplasts where photosynthetic activity takes place. Their CO2 loading-dependent fluorescence verifies that, in vivo, they maintain their abi l i t y to capture CO2 and can be therefore reloaded with atmospheric CO2 while in planta. Our results contribute to the development of a nanomaterials-based CO2-concentrating mechanism in plants t h a t can potentially increase photosynthetic efficiency and overall plants' CO2 storage

Metatranscriptomics captures dynamic shifts in mycorrhizal coordination in boreal forests

Carbon storage and cycling in boreal forests—the largest terrestrial carbon store—ismoderated by complex interactions between trees and soil microorganisms. However,existing methods limit our ability to predict how changes in environmental conditionswill alter these associations and the essential ecosystem services they provide. To addressthis, we developed a metatranscriptomic approach to analyze the impact of nutrientenrichment on Norway sprucefine roots and the community structure, function, andtree–microbe coordination of over 350 root-associated fungal species. In response toaltered nutrient status, host trees redefined their relationship with the fungal commu-nity by reducing sugar efflux carriers and enhancing defense processes. This resulted ina profound restructuring of the fungal community and a collapse in functional coordi-nation between the tree and the dominant Basidiomycete species, and an increase infunctional coordination with versatile Ascomycete species. As such, there was a func-tional  shift  in  community  dominance  from  Basidiomycetes  species,  with  importantroles in enzymatically cycling recalcitrant carbon, to Ascomycete species that have mela-nized cell walls that are highly resistant to degradation. These changes were accompa-nied  by  prominent  shifts  in  transcriptional  coordination  between  over  60  predictedfungal effectors, with more than 5,000 Norway spruce transcripts, providing mechanis-tic insight into the complex molecular dialogue coordinating host trees and their fungalpartners. The host–microbe dynamics captured by this study functionally inform howthese complex and  sensitive biological  relationships may mediate  the carbon  storagepotential of boreal soils under changing nutrient conditions

Analyse fonctionnelle d'effecteurs fongiques impliqués dans le développement de la symbiose ectomycorhizienne Laccaria bicolor-Populus trichocarpa

Roots of most trees form symbiosis with mutualistic soil-borne fungi. The ectomycorrhizal basidiomycete L. bicolor (Maire) P.D. Orton relies on mycorrhizal-induced small secreted proteins (MiSSP) to establish symbiotic tissues in the host-plant. The host proteins targeted by these fungal effectors are yet unknown. In the present study, we used the binary yeast two-hybrid (Y2H) system to determine direct interactions between MiSSP7 and the plant proteins in the L. bicolor-P. trichocarpa ectomycorrhizae. We showed that MiSSP7 interact with the jasmonic acid (JA) co-receptors JAZ5 and JAZ6 of P. trichocarpa, blocking JA signaling and promoting mutualism. L. bicolor transformants with severely reduced expression of MiSSP7 did not enter into symbiosis with poplar roots, a phenotype that could be complemented by transgenically varying the transcription of PtJAZ6 or through inhibiting JA signalling. Additional Y2H assays showed that PtJAZ6 protein form a regulatory complex involving 14-3-3 protein(s) and MYC transcriptional factors. Two others L. bicolor effector-like proteins, MiSSP8 and MiSSP17, are secreted and are essential for the symbiosis development. Y2H assays suggested that these MiSSPs interact with plant proteins involved in plant defence signalling pathways. During symbiosis development, L. bicolor experiences important genetic reprogramming required for root colonization. Transcription factors (TFs) are key players of these genetic changes. Here, we developed high throughput analysis of TFs in L. bicolor to obtain a comprehensive inventory of significantly regulated transcription factors in ECMLes racines de la plupart des arbres forment des symbioses ectomycorhiziennes avec les champignons mutualistes du sol. Le basidiomycète L. bicolor (Maire) P.D. Orton secrète de petites protéines effectrices (MiSSP) afin d'établir les structures symbiotiques. Toutefois, les protéines de l'hôte ciblées par les MiSSPs ne sont pas connues. Dans notre étude, nous démontrons, à l'aide du système double hybride chez la levure (Y2H), que la protéine MiSSP7 interagit avec les co-récepteurs de l'acide jasmonique (AJ) JAZ5 et JAZ6 de P. trichocarpa. Cette interaction entraine un blocage de la voie de signalisation de l'AJ et favorise le développement symbiotique. Des transformants de L. bicolor, dont l'expression de MiSSP7 est fortement réduite, ne sont plus capables de mycorhizer les racines du peuplier. Une variation transgénique de la transcription de PtJAZ6 ou l'inhibition de la voie de signalisation de l'AJ complémente ce phénotype. Nous avons également montré que la protéine PtJAZ6 interagit avec une protéine de type 14-3-3 et un facteur de transcription de type MYC, formant un complexe de régulation. Deux autres protéines effectrices, MiSSP8 et MiSSP17, sont sécrétées et essentielles au développement symbiotique. Les résultats des analyses Y2H suggèrent que MiSSP8 et MiSSP17 pourraient aider au contournement des réactions de défense de la plante-hôte. Au cours du développement symbiotique, le champignon est le siège d'une reprogrammation génétique importante. Les facteurs de transcription (TFs) sont les principaux acteurs de ces changements génétiques. Nous avons donc étudié les TFs de L. bicolor afin d'obtenir un inventaire complet des TFs régulés par la mycorhizatio

Identifying targets of fungal effectors in the ectomycorrhizal symbiosis Laccaria bicolor-Populus trichocarpa

Les racines de la plupart des arbres forment des symbioses ectomycorhiziennes avec les champignons mutualistes du sol. Le basidiomycète L. bicolor (Maire) P.D. Orton secrète de petites protéines effectrices (MiSSP) afin d'établir les structures symbiotiques. Toutefois, les protéines de l'hôte ciblées par les MiSSPs ne sont pas connues. Dans notre étude, nous démontrons, à l'aide du système double hybride chez la levure (Y2H), que la protéine MiSSP7 interagit avec les co-récepteurs de l'acide jasmonique (AJ) JAZ5 et JAZ6 de P. trichocarpa. Cette interaction entraine un blocage de la voie de signalisation de l'AJ et favorise le développement symbiotique. Des transformants de L. bicolor, dont l'expression de MiSSP7 est fortement réduite, ne sont plus capables de mycorhizer les racines du peuplier. Une variation transgénique de la transcription de PtJAZ6 ou l'inhibition de la voie de signalisation de l'AJ complémente ce phénotype. Nous avons également montré que la protéine PtJAZ6 interagit avec une protéine de type 14-3-3 et un facteur de transcription de type MYC, formant un complexe de régulation. Deux autres protéines effectrices, MiSSP8 et MiSSP17, sont sécrétées et essentielles au développement symbiotique. Les résultats des analyses Y2H suggèrent que MiSSP8 et MiSSP17 pourraient aider au contournement des réactions de défense de la plante-hôte. Au cours du développement symbiotique, le champignon est le siège d'une reprogrammation génétique importante. Les facteurs de transcription (TFs) sont les principaux acteurs de ces changements génétiques. Nous avons donc étudié les TFs de L. bicolor afin d'obtenir un inventaire complet des TFs régulés par la mycorhizationRoots of most trees form symbiosis with mutualistic soil-borne fungi. The ectomycorrhizal basidiomycete L. bicolor (Maire) P.D. Orton relies on mycorrhizal-induced small secreted proteins (MiSSP) to establish symbiotic tissues in the host-plant. The host proteins targeted by these fungal effectors are yet unknown. In the present study, we used the binary yeast two-hybrid (Y2H) system to determine direct interactions between MiSSP7 and the plant proteins in the L. bicolor-P. trichocarpa ectomycorrhizae. We showed that MiSSP7 interact with the jasmonic acid (JA) co-receptors JAZ5 and JAZ6 of P. trichocarpa, blocking JA signaling and promoting mutualism. L. bicolor transformants with severely reduced expression of MiSSP7 did not enter into symbiosis with poplar roots, a phenotype that could be complemented by transgenically varying the transcription of PtJAZ6 or through inhibiting JA signalling. Additional Y2H assays showed that PtJAZ6 protein form a regulatory complex involving 14-3-3 protein(s) and MYC transcriptional factors. Two others L. bicolor effector-like proteins, MiSSP8 and MiSSP17, are secreted and are essential for the symbiosis development. Y2H assays suggested that these MiSSPs interact with plant proteins involved in plant defence signalling pathways. During symbiosis development, L. bicolor experiences important genetic reprogramming required for root colonization. Transcription factors (TFs) are key players of these genetic changes. Here, we developed high throughput analysis of TFs in L. bicolor to obtain a comprehensive inventory of significantly regulated transcription factors in EC

Analyse fonctionnelle d'effecteurs fongiques impliqués dans le développement de la symbiose ectomycorhizienne Laccaria bicolor-Populus trichocarpa

Les racines de la plupart des arbres forment des symbioses ectomycorhiziennes avec les champignons mutualistes du sol. Le basidiomycète L. bicolor (Maire) P.D. Orton secrète de petites protéines effectrices (MiSSP) afin d'établir les structures symbiotiques. Toutefois, les protéines de l'hôte ciblées par les MiSSPs ne sont pas connues. Dans notre étude, nous démontrons, à l'aide du système double hybride chez la levure (Y2H), que la protéine MiSSP7 interagit avec les co-récepteurs de l'acide jasmonique (AJ) JAZ5 et JAZ6 de P. trichocarpa. Cette interaction entraine un blocage de la voie de signalisation de l'AJ et favorise le développement symbiotique. Des transformants de L. bicolor, dont l'expression de MiSSP7 est fortement réduite, ne sont plus capables de mycorhizer les racines du peuplier. Une variation transgénique de la transcription de PtJAZ6 ou l'inhibition de la voie de signalisation de l'AJ complémente ce phénotype. Nous avons également montré que la protéine PtJAZ6 interagit avec une protéine de type 14-3-3 et un facteur de transcription de type MYC, formant un complexe de régulation. Deux autres protéines effectrices, MiSSP8 et MiSSP17, sont sécrétées et essentielles au développement symbiotique. Les résultats des analyses Y2H suggèrent que MiSSP8 et MiSSP17 pourraient aider au contournement des réactions de défense de la plante-hôte. Au cours du développement symbiotique, le champignon est le siège d'une reprogrammation génétique importante. Les facteurs de transcription (TFs) sont les principaux acteurs de ces changements génétiques. Nous avons donc étudié les TFs de L. bicolor afin d'obtenir un inventaire complet des TFs régulés par la mycorhizationRoots of most trees form symbiosis with mutualistic soil-borne fungi. The ectomycorrhizal basidiomycete L. bicolor (Maire) P.D. Orton relies on mycorrhizal-induced small secreted proteins (MiSSP) to establish symbiotic tissues in the host-plant. The host proteins targeted by these fungal effectors are yet unknown. In the present study, we used the binary yeast two-hybrid (Y2H) system to determine direct interactions between MiSSP7 and the plant proteins in the L. bicolor-P. trichocarpa ectomycorrhizae. We showed that MiSSP7 interact with the jasmonic acid (JA) co-receptors JAZ5 and JAZ6 of P. trichocarpa, blocking JA signaling and promoting mutualism. L. bicolor transformants with severely reduced expression of MiSSP7 did not enter into symbiosis with poplar roots, a phenotype that could be complemented by transgenically varying the transcription of PtJAZ6 or through inhibiting JA signalling. Additional Y2H assays showed that PtJAZ6 protein form a regulatory complex involving 14-3-3 protein(s) and MYC transcriptional factors. Two others L. bicolor effector-like proteins, MiSSP8 and MiSSP17, are secreted and are essential for the symbiosis development. Y2H assays suggested that these MiSSPs interact with plant proteins involved in plant defence signalling pathways. During symbiosis development, L. bicolor experiences important genetic reprogramming required for root colonization. Transcription factors (TFs) are key players of these genetic changes. Here, we developed high throughput analysis of TFs in L. bicolor to obtain a comprehensive inventory of significantly regulated transcription factors in ECMMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Unravel the Local Complexity of Biological Environments by MALDI Mass Spectrometry Imaging

Classic metabolomic methods have proven to be very useful to study functional biology and variation in the chemical composition of different tissues. However, they do not provide any information in terms of spatial localization within fine structures. Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) does and reaches at best a spatial resolution of 0.25 mu m depending on the laser setup, making it a very powerful tool to analyze the local complexity of biological samples at the cellular level. Here, we intend to give an overview of the diversity of the molecules and localizations analyzed using this method as well as to update on the latest adaptations made to circumvent the complexity of samples. MALDI MSI has been widely used in medical sciences and is now developing in research areas as diverse as entomology, microbiology, plant biology, and plant-microbe interactions, the rhizobia symbiosis being the most exhaustively described so far. Those are the fields of interest on which we will focus to demonstrate MALDI MSI strengths in characterizing the spatial distributions of metabolites, lipids, and peptides in relation to biological questions