PLANTdataHUB: a collaborative platform for continuous FAIR data sharing in plant research.

In modern reproducible, hypothesis-driven plant research, scientists are increasingly relying on research data management (RDM) services and infrastructures to streamline the processes of collecting, processing, sharing, and archiving research data. FAIR (i.e., findable, accessible, interoperable, and reusable) research data play a pivotal role in enabling the integration of interdisciplinary knowledge and facilitating the comparison and synthesis of a wide range of analytical findings. The PLANTdataHUB offers a solution that realizes RDM of scientific (meta)data as evolving collections of files in a directory - yielding FAIR digital objects called ARCs - with tools that enable scientists to plan, communicate, collaborate, publish, and reuse data on the same platform while gaining continuous quality control insights. The centralized platform is scalable from personal use to global communities and provides advanced federation capabilities for institutions that prefer to host their own satellite instances. This approach borrows many concepts from software development and adapts them to fit the challenges of the field of modern plant science undergoing digital transformation. The PLANTdataHUB supports researchers in each stage of a scientific project with adaptable continuous quality control insights, from the early planning phase to data publication. The central live instance of PLANTdataHUB is accessible at (https://git.nfdi4plants.org), and it will continue to evolve as a community-driven and dynamic resource that serves the needs of contemporary plant science.

A Powerful P-N Connection: Preparative Approaches, Reactivity, and Applications of P-Stereogenic Aminophosphines.

For more than five decades, P-stereogenic aminophosphine chalcogenides and boranes have attracted scientific attention and are still in the focus of ongoing research. In the last years, novel transition metal-based synthesis methods have been discovered, in addition to the long-known use of chiral auxiliaries. Enantiomerically pure compounds with N-P+-X- (X=O, S, BH3) motifs served as valuable reactive building blocks to provide new classes of organophosphorus derivatives, thereby preserving the stereochemical information at the phosphorus atom. Over the years, intriguing applications in organocatalysis and transition metal catalysis have been reported for some representatives. Asymmetric reductions of C=C, C=N, and C=O double bonds were feasible with selected P-stereogenic aminophosphine oxides in the presence of hydrogen transfer reagents. P-stereogenic aminophosphine boranes could be easily deprotected and used as ligands for various transition metals to enable catalytic asymmetric hydrogenations of olefins and imines. This review traces the emergence of a synthetically and catalytically powerful functional compound class with phosphorus-centered chirality in its main lines, starting from classical approaches to modern synthesis methods to current applications.

Measuring leaf and root functional traits uncovers multidimensionality of plant responses to arbuscular mycorrhizal fungi.

PREMISE: While many studies have measured the aboveground responses of plants to mycorrhizal fungi at a single time point, little is known about how plants respond belowground or across time to mycorrhizal symbiosis. By measuring belowground responses and growth over time in many plant species, we create a more complete picture of how mycorrhizal fungi benefit their hosts. METHODS: We grew 26 prairie plant species with and without mycorrhizal fungi and measured 14 functional traits to assess above- and belowground tissue quality and quantity responses and changes in resource allocation. We used function-valued trait (FVT) modeling to characterize changes in species growth rate when colonized. RESULTS: While aboveground biomass responses were positive, the response of traits belowground were much more variable. Changes in aboveground biomass accounted for 60.8% of the variation in mycorrhizal responses, supporting the use of aboveground biomass response as the primary response trait. Responses belowground were not associated with aboveground responses and accounted for 18.3% of the variation. Growth responses over time were highly variable across species. Interestingly, none of the measured responses were phylogenetically conserved. CONCLUSIONS: Mycorrhizal fungi increase plant growth in most scenarios, but the effects of these fungi belowground and across time are more complicated. This study highlights how differences in plant allocation priorities might affect how they utilize the benefits from mycorrhizal fungi. Identifying and characterizing these differences is a key step to understanding the effects of mycorrhizal mutualisms on whole plant physiology.

High avoidance and low approach motivation affect cognitive reappraisal generation in the face of anger.

This study investigates the link between the revised reinforcement sensitivity theory (RST) and individuals' capacity to spontaneously invent alternate appraisals for aversive events. Eighty-two women completed the Reappraisal Inventiveness Test for anger-eliciting situations, and quantity and quality of reappraisal ideas were correlated with BIS, BAS, and FFFS sensitivity (RST-Personality Questionnaire). Results revealed that high BIS and high FFFS reduced the total number of reappraisal ideas, indicating that combined heightened sensitivity of the two avoidance systems may deplete individuals' repertoire of potential reappraisals. RST effects on the quality of generated reappraisals were also found. High BIS and low BAS lowered individuals' propensity to produce positive re-interpretations, which are considered a more adaptive reappraisal tactic. High FFFS sensitivity was linked to a lower preference for problem-oriented reappraisals. This study underlines that certain interactions of motivational subsystems may be particularly detrimental for successful reappraisal of anger-eliciting events. Our findings reveal potential links between revised RST effects and adaptive emotion regulation.

Molecular Scissors for Tailor-Made Modification of Siloxane Scaffolds.

The controlled design of functional oligosiloxanes is an important topic in current research. A consecutive Si-O-Si bond cleavage/formation using siloxanes that are substituted with 1,2-diaminobenzene derivatives acting as molecular scissors is presented. The method allows to cut at certain positions of a siloxane scaffold forming a cyclic diaminosilane or -siloxane intermediate and then to introduce new functional siloxy units. The procedure could be extended to a direct one-step cleavage of chlorooligosiloxanes. Both siloxane formation and cleavage proceed with good to excellent yields, high regioselectivity, and great variability of the siloxy units. Control of the selectivity is achieved by the choice of the amino substituent. Insight into the mechanism was provided by low temperature NMR studies and the isolation of a lithiated intermediate.

Access to Enantiomerically Pure P-Stereogenic Primary Aminophosphine Sulfides under Reductive Conditions.

Stereochemically pure phosphines with phosphorus-heteroatom bonds and P-centered chirality are a promising class of functional building blocks for the design of chiral ligands and organocatalysts. A route to enantiomerically pure primary aminophosphine sulfides was opened through stereospecific reductive C-N bond cleavage of phosphorus(V) precursors by lithium in liquid ammonia. The chemoselectivity of the reaction as a function of reaction time, substrate pattern, and chiral auxiliary was investigated. In the presence of exclusively aliphatic groups bound to the phosphorus atom, all competing reductive side reactions are totally prevented. The absolute configurations of all P-stereogenic compounds were determined by single-crystal X-ray diffraction analysis. Their use as synthetic building blocks was demonstrated. The lithium salt of (R)-BINOL-dithiophosphoric acid proved to be a useful stereochemical probe to determine the enantiomeric purity. Insights into the coordination mode of the lithium-based chiral complex formed in solution was provided by NMR spectroscopy and DFT calculations.

Structural and Electronic Effects on Phosphine Chalcogenide Stabilized Silicon Centers in Four-Membered Heterocyclic Cations.

Understanding the interplay of structural and electronic parameters in the stabilization of Lewis acidic silicon centers is crucial for stereochemical questions and applications in bond activation and catalytic transformations. Phosphine chalcogenide functionalized (Ch = O, S, and Se) hydrosilanes having tert-butyl and 2,4,6-trimethoxyphenyl (TMP) substituents on the silicon atom were synthesized, and the ring-closing reactions to afford the heterocyclic four-membered CPChSi cations were investigated. Synthetic access was only achieved for the sulfur- and selenium-based cations. A thorough study by means of single-crystal X-ray structure determination, NMR spectroscopic data, and density functional theory (DFT) calculations provided insight into important electronic and structural parameters affecting the stability of the intramolecularly stabilized cations. Detailed structural considerations were made on the contributions to the ring strain (angular strain and steric repulsion). Thermochemical investigations showed that the substituents on the silicon and phosphorus atoms play an important role for the stability of the cationic heterocycles. In the absence of large steric repulsions through bulky substituents (methyl groups on silicon and tert-butyl groups on phosphorus), an intrinsic stability sequence of the intramolecular Ch-Si coordination depending on the chalcogen atom in the direction Se ≤ S < O can be observed. However, the order is reversed (O < S < Se) in the case of strong repulsions between sterically demanding substituents (tert-butyl groups on both silicon and phosphorus atoms). Natural bond orbital (NBO) analysis supported the explanations for the observed deshielding trends in 31P NMR spectroscopy and revealed that the O-Si bond is more ionic in nature compared to the S-Si and Se-Si bonds, with the latter exhibiting higher covalent character due to a more efficient charge transfer through a σ-type nCh → pSi interaction.

Easy Access to Enantiomerically Pure Heterocyclic Silicon-Chiral Phosphonium Cations and the Matched/Mismatched Case of Dihydrogen Release.

Phosphonium ions are widely used in preparative organic synthesis and catalysis. The provision of new types of cations that contain both functional and chiral information is a major synthetic challenge and can open up new horizons in asymmetric cation-directed and Lewis acid catalysis. We discovered an efficient methodology towards new Si-chiral four-membered CPSSi* heterocyclic cations. Three synthetic approaches are presented. The stereochemical sequence of anchimerically assisted cation formation with B(C6 F5 )3 and subsequent hydride addition was fully elucidated and proceeds with excellent preservation of the chiral information at the stereogenic silicon atom. Also the mechanism of dihydrogen release from a protonated hydrosilane was studied in detail by the help of Si-centered chirality as stereochemical probe. Chemoselectivity switch (dihydrogen release vs. protodesilylation) can easily be achieved through slight modifications of the solvent. A matched/mismatched case was identified and the intermolecularity of this reaction supported by spectroscopic, kinetic, deuterium-labeling experiments, and quantum chemical calculations.

Primary Amine Functionalization of Alkoxysilanes: Synthesis, Selectivity, and Mechanistic Insights.

We report a highly selective substitution of silicon-bound methoxy groups by primary lithium amides. This unusual reactivity is possible because of the formation of particularly stable lithium methoxide, which compensates for the decreased Si-N bond enthalpy compared to Si-O bonds. In contrast to substitution reactions on halosilanes, highly selective monosubstitutions under mild conditions are possible, even in the presence of further reactive methoxy groups. A combination of experiments and density functional theory calculations was carried out in order to get an extensive understanding of the reaction. The calculations reveal a possible reaction mechanism with considerably low activation barriers and the entry of the nucleophile to be the rate-determining step. The low activation energies allow for the substitutions to be carried out at low temperatures, therefore preventing side reactions from occurring. The presented investigations expand the view of fundamental transformation processes on silicon and give access to a wide variety of functionalized silicon-based building blocks for various fields of chemistry.

Local adaptation of mycorrhizae communities changes plant community composition and increases aboveground productivity.

Soil microbial communities can have an important role in the adaptation of plants to their local abiotic soil conditions and in mediating plant responses to environmental stress. This has been clearly demonstrated for individual plant species, but it is unknown how locally adapted microbes may affect plant communities. It is possible that the adaptation of microbial communities to local conditions can shape plant community composition. Additionally, it is possible that the effects of locally adapted microorganisms on individual plant species could be altered by co-occurring plant species. We tested these possibilities in plant community mesocosms with soils and mycorrhizal fungi (AMF) from three locations. We found that plant community biomass responded positively to local adaptation of AMF to soil conditions. Plant community composition also changed in response to local adaptation of AMF. Unexpectedly, the strongest benefits of locally adapted AMF went to early successional plant species that have the highest relative growth rates and the lowest responsiveness to the presence of AMF. Late successional plants that responded positively overall to the presence of AMF were often suppressed in communities with local AMF, perhaps because of strong competition from fast growing plant species. These results show that local adaptation of soil microbial communities can shape plant community composition, and the benefits that plants derive from locally adapted microorganisms can be reshaped by the competitive context in which these associations occur.

When and where plant-soil feedback may promote plant coexistence: a meta-analysis.

Plant-soil feedback (PSF) theory provides a powerful framework for understanding plant dynamics by integrating growth assays into predictions of whether soil communities stabilise plant-plant interactions. However, we lack a comprehensive view of the likelihood of feedback-driven coexistence, partly because of a failure to analyse pairwise PSF, the metric directly linked to plant species coexistence. Here, we determine the relative importance of plant evolutionary history, traits, and environmental factors for coexistence through PSF using a meta-analysis of 1038 pairwise PSF measures. Consistent with eco-evolutionary predictions, feedback is more likely to mediate coexistence for pairs of plant species (1) associating with similar guilds of mycorrhizal fungi, (2) of increasing phylogenetic distance, and (3) interacting with native microbes. We also found evidence for a primary role of pathogens in feedback-mediated coexistence. By combining results over several independent studies, our results confirm that PSF may play a key role in plant species coexistence, species invasion, and the phylogenetic diversification of plant communities.

Catalytic Enantioselective Synthesis of a Pyrrolizidine-Alkaloid-Inspired Compound Collection with Antiplasmodial Activity.

A novel enantioselective approach to the synthesis of a compound collection inspired by natural pyrrolizidine alkaloids was developed, employing an enantioselectively catalyzed 1,3-dipolar cycloaddition as the key step. The cycloadducts were obtained with excellent enantio- and diastereoselectivity. Biological evaluation of the resulting compound collection revealed that the compound class has multiple bioactivities, including activity against Plasmodium falciparum 3D7 and inhibition of Hedgehog signaling.

Negative plant-phyllosphere feedbacks in native Asteraceae hosts - a novel extension of the plant-soil feedback framework.

Over the past 25 years, the plant-soil feedback (PSF) framework has catalyzed our understanding of how belowground microbiota impact plant fitness and species coexistence. Here, we apply a novel extension of this framework to microbiota associated with aboveground tissues, termed 'plant-phyllosphere feedback (PPFs)'. In parallel greenhouse experiments, rhizosphere and phyllosphere microbiota of con- and heterospecific hosts from four species were independently manipulated. In a third experiment, we tested the combined effects of soil and phyllosphere feedback under field conditions. We found that three of four species experienced weak negative PSF whereas, in contrast, all four species experienced strong negative PPFs. Field-based feedback estimates were highly negative for all four species, though variable in magnitude. Our results suggest that phyllosphere microbiota, like rhizosphere microbiota, can potentially mediate plant species coexistence via negative feedbacks. Extension of the PSF framework to the phyllosphere is needed to more fully elucidate plant-microbiota interactions.

Selective Si-C(sp3 ) Bond Cleavage in (Aminomethyl)silanes by Carbanionic Nucleophiles and Its Stereochemical Course.

Selective cleavage of a silicon-carbon bond in tetraorganosilanes is still a great challenge. A new type of Si-C(sp3 ) bond cleavage in bench-stable (aminomethyl)silanes with common organolithium reagents as nucleophiles has now been identified. Suitable leaving groups are benzyl, allyl, and phenylthiomethyl groups. A ß-donor function and polar solvents are essential for the reaction. Simple switching between α-deprotonation and substitution is possible through slight modifications of the reaction conditions. The stereochemical course of the reaction was elucidated by using a silicon-chiral benzylsilane. The new transformation proceeds stereospecifically with inversion of configuration and can be used for the targeted synthesis of enantiomerically pure tetraorganosilanes, which are otherwise difficult to access. Quantum chemical calculations provided insight into the mechanism of the new substitution.

Suppressing the Rayleigh-Plateau Instability in Field-Directed Colloidal Assembly.

Suspensions of superparamagnetic colloids that equilibrate in a toggled magnetic field undergo a Rayleigh-Plateau instability with a characteristic wavelength λ = 600 µm for the toggle frequency ν = 0.66 Hz. The instability is suppressed when the chamber length L in the field direction is less than 2λ. The final size of the magnetic domains perpendicular to the field, D, follows a power law relation of D ∼ L(0.71±0.07). These results demonstrate the structural differences of field-directed suspensions when confined to lengths scale set by the phase separation process and can potentially be used to create self-assembled colloidal crystals with well-defined size and shape.

Synthesis of an Iridoid-Inspired Compound Collection and Discovery of Autophagy Inhibitors.

Iridoids comprise a large group of monoterpenoid natural products displaying a diverse array of biological activities ranging from neurotrophic to anti-inflammatory and anti-tumorigenic properties. Therefore, the development of concise synthesis routes to compound collections inspired by the structural features of these natural products is of particular relevance for chemical biology and medicinal chemistry. Herein we describe a samarium diiodide-mediated synthesis of a small, focused iridoid-inspired compound collection. Characterization of these iridoid analogues in biological assays revealed novel small-molecule inhibitors of autophagy.

Stereocontrol in nucleophilic substitution reactions at silicon: the role of permutation in generating silicon-centered chirality.

Intramolecular isomerization in pentacoordinate compounds can play an essential role for the adjustment of defined stereochemical information. Here, we present a conclusive mechanism of a stereocontrolled reaction on chiral dimethoxysilanes that opens new aspects in understanding the origin of creating silicon-centered chirality during a nucleophilic substitution process. By combining experimental, structural, and quantum chemical methods, we were able to disclose an interconversion process, based on consecutive Berry-type motions, as the most plausible mechanism for describing the stereochemical outcome in suchlike substitution reactions.

Stereoselective synthesis of a natural product inspired tetrahydroindolo[2,3-a]-quinolizine compound library.

A natural product-inspired synthesis of a compound collection embodying the tetrahydroindolo[2,3-a]quinolizine scaffold was established with a five step synthesis route. An imino-Diels-Alder reaction between Danishefsky's diene and the iminoesters derived from tryptamines was used as a key reaction. Reductive amination of the ketone function and amide synthesis with the carboxylic acid derived from the ethyl ester, were used to decorate the core scaffold. Thus a compound library of 530 tetrahydroindolo[2,3-a]quinolizines was generated and submitted to European lead factory consortium for various biological screenings.

Antiplasmodial and Cytotoxic Triterpenoids from the Bark of the Cameroonian Medicinal Plant Entandrophragma congoënse.

Eight new triterpenoids, prototiamins A-G (1-6, 9) and seco-tiaminic acid A (10), were isolated along with four known compounds from the bark of Entandrophragma congoënse. Their structures were elucidated by means of HRMS and different NMR techniques and chemical transformations. Assignments of relative and absolute configurations for the new compounds were achieved using NOESY experiments and by chemical modification including the advanced Mosher's method. Additionally, the structure and relative configuration of compound 3 were confirmed by single-crystal X-ray diffraction analysis. Compounds 1, 3, and 5 displayed significant in vitro antiplasmodial activity against the erythrocytic stages of chloroquine-sensitive Plasmodium falciparum strain NF54. Prototiamin C (3) was the most potent of the compounds isolated, with an IC50 value of 0.44 µM. All compounds tested showed low cytotoxicity for the L6 rat skeletal myoblast cell line.

Coarsening mechanics of a colloidal suspension in toggled fields.

Suspensions of paramagnetic colloids are driven to phase separate and self-assemble in toggled magnetic fields. At field strengths above 575 A/m and toggle frequencies between 0.66 and 2 Hz, an initial gel-like, arrested network collapses into condensed, ellipsoidal aggregates. The evolution to this equilibrium structure occurs via a Rayleigh-Plateau instability. The toggle frequency ν determines the fluidity of the breakup process. At frequencies between 0.66 and 1.5 Hz, the suspension breaks up similar to a viscous, Newtonian fluid. At frequencies ν > 1.5 Hz, the network ruptures like a viscoplastic material. The field strength alters the onset time of the instability. A power law relationship emerges as the scaled frequency and field strength can be used to predict the onset of breakup. These results further aid in understanding the mechanics and dynamics of the phase separation process of suspensions of polarizable colloids in toggled external fields.