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Inheritance and gift taxation vary widely among countries in both the design and tax burden. We analyze the impact of a series of factors, such as the country’s affluence, political preferences, preferences for equity, aging ratio, fiscal standing of the state, and the country’s size, on inheritance tax systems. The applied methods involve the random effects ordered logistic regression for tax design and tobit correlated-random effect models for tax revenues. We find that inheritance tax design is mainly determined by demographic factors while tax revenues depend on a broader group of factors including political orientation of a state, condition of an economy, and the size of a country. Higher preferences for equal distribution and commitment to democratic norms are associated with higher tax revenues. Good economic condition of the state boosts revenues, as does country’s higher population. The results shed some light on future evolution of inheritance taxation.

Diurnal light-dark cycles regulate nutrient uptake and transport; however, the underlying molecular mechanisms remain largely unknown. Transcription factor MYB59 and ion transporter NPF7.3 participate in root-to-shoot K + /NO 3 - translocation in Arabidopsis. In this study, transcriptional analyses and western blotting experiments revealed the diurnal expression of the MYB59-NPF7.3 module. ChIP-qPCR and EMSA showed that transcription factors HY5 and PIF directly bind to the MYB59 promoter. Phenotype analyses and ion content measurement indicated that HY5 and PIF antagonistically control root-to-shoot K + /NO 3 - translocation through the MYB59-NPF7.3 module. We found HY5 proteins accumulate in roots and repress MYB59 transcription during daytime, while PIF proteins promote MYB59 transcription in the dark. The expression levels of the NPF7.3 transcript and protein are gradually decreased during daytime, but increased at night. The enhancement of K + /NO 3 - loading into the xylem mediated by NPF7.3 could increase root pressure at night, which maintained the root-to-shoot water/nutrient translocation. This study reveals a synergistic mechanism between light signaling and nutrient transport in plants, and defines a diurnal molecular switch of driving forces for root-to-shoot water/nutrient translocation., (© 2025 The Author(s). New Phytologist © 2025 New Phytologist Foundation.)

Systemic signaling is an essential hallmark of multicellular life. Pathogen encounter occurs locally but triggers organ-scale and organismic immune responses. In plants, elicitor perception provokes systemically expanding Ca 2+ and H 2 O 2 signals conferring immunity. Here, we identify a Ca 2+ sensing bi-kinase module as becoming super-activated through mutual phosphorylation and as imposing synergistically enhanced NADPH oxidase activation. A combined two-layer bi-kinase/substrate phospho-code allows for sensitized signaling initiation already by near-resting elevations of Ca 2+ concentration. Subsequently, it facilitates further signal wave proliferation with minimal Ca 2+ amplitude requirement, triggering protective defense responses throughout the plant. Our study reveals how plants build and perpetuate trans-cellular immune signal proliferation while avoiding disturbance of ongoing cellular signaling along the path of response dissemination.

Chloride (Cl - ) ions cause major damage to crops in saline soils. Understanding the key factors that influence Cl - uptake and translocation will aid the breeding of more salt-tolerant crops. Here, using genome-wide association study and transcriptomic analysis, we identified a NITRATE TRANSPORTER 1 (NRT1)/PEPTIDE TRANSPORTER family (NPF) protein, GmNPF7.5, as the dominant gene locus influencing Cl - homeostasis in soybean (Glycine max). A natural SNP variation resulted in two haplotypes (GmNPF7.5 HapA and GmNPF7.5 HapB ), which was associated with Cl - content. GmNPF7.5 HapA mediated Cl - or nitrate (NO 3 - ) uptake in a pH-dependent manner and exhibited higher permeability for Cl - over NO 3 - . The suppression of GmNPF7.5 HapA expression decreased Cl - accumulation and salt damage in plants, whereas its overexpression showed the opposite effects. The elite haplotype GmNPF7.5 HapB diminished Cl - transport activity independently from NO 3 - permeability, thus enhancing soybean salt tolerance. Furthermore, the protein kinase GmPI4Kγ4 could phosphorylate GmNPF7.5, which repressed Cl - uptake without affecting NO 3 - permeability. Our findings define a regulatory mechanism for Cl - control under NaCl stress, providing a strategy for the improvement of salt tolerance in soybean plants., Competing Interests: Disclosure and competing interests statement. The authors declare no competing interests., (© 2025. The Author(s).)

Date palm (Phoenix dactylifera L.) is an important crop in arid regions that is well-adapted to desert ecosystems. To understand the remarkable ability to grow and yield in water-limited environments, experiments with water-withholding for up to four weeks were conducted. In response to drought, root, rather than leaf, osmotic strength increased, with organic solutes such as sugars and amino acids contributing more to the osmolyte increase than minerals. Consistently, carbon and amino acid metabolism was acclimated toward biosynthesis at both the transcriptional and translational levels. In leaves, a remodeling of membrane systems was observed, suggesting changes in thylakoid lipid composition, which together with the restructuring of the photosynthetic apparatus, indicated an acclimation preventing oxidative damage. Thus, xerophilic date palm avoids oxidative damage under drought by combined prevention and rapid detoxification of oxygen radicals. Although minerals were expected to serve as cheap key osmotics, date palm also relies on organic osmolytes for osmotic adjustment of the roots during early drought acclimation. The diversion of these resources away from growth is consistent with date palm's strategy of generally slow growth in harsh environments and clearly indicates a trade-off between growth and stress-related physiological responses., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

Date palm (Phoenix dactylifera L.) is able to grow and complete its life cycle while being rooted in highly saline soils. Which of the many well-known salt-tolerance strategies are combined to fine-tune this remarkable resilience is unknown. The precise location, whether in the shoot or the root, where these strategies are employed remains uncertain, leaving us unaware of how the various known salt-tolerance mechanisms are integrated to fine-tune this remarkable resilience. To address this shortcoming, we exposed date palm to a salt stress dose equivalent to seawater for up to 4 weeks and applied integrative multi-omics analyses followed by targeted metabolomics, hormone, and ion analyses. Integration of proteomic into transcriptomic data allowed a view beyond simple correlation, revealing a remarkably high degree of convergence between gene expression and protein abundance. This sheds a clear light on the acclimatization mechanisms employed, which depend on reprogramming of protein biosynthesis. For growth in highly saline habitats, date palm effectively combines various salt-tolerance mechanisms found in both halophytes and glycophytes: "avoidance" by efficient sodium and chloride exclusion at the roots, and "acclimation" by osmotic adjustment, reactive oxygen species scavenging in leaves, and remodeling of the ribosome-associated proteome in salt-exposed root cells. Combined efficiently as in P. dactylifera L., these sets of mechanisms seem to explain the palm's excellent salt stress tolerance., (© 2023 The Authors. The Plant Genome published by Wiley Periodicals LLC on behalf of Crop Science Society of America.)

Gadolinium-based contrast agents (GBCAs) are found increasingly in different water bodies, making the investigation of their uptake and distribution behavior in plants a matter of high interest to assess their potential effects on the environment. Depending on the used complexing agent, they are classified into linear or macrocyclic GBCAs, with macrocyclic complexes being more stable. In this study, by using TbCl 3 , Gd-DTPA-BMA, and Eu-DOTA as model compounds for ionic, linear, and macrocyclic lanthanide species, the elemental species-dependent uptake into leaves of Arabidopsis thaliana under identical biological conditions was studied. After growing for 14 days on medium containing the lanthanide species, the uptake of all studied compounds was confirmed by means of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Furthermore, the uptake rate of TbCl 3 and the linear Gd-DTPA-BMA was similar, with Tb and Gd hotspots colocated in the areas of hydathodes and the trichomes of the leaves. In contrast, in the case of the macrocyclic Eu-DOTA, Eu was mainly located in the leaf veins. Additionally, Eu was colocated with Tb and Gd in the hydathode at the tip of the leave. Removal of the lanthanide species from the medium led to a decrease in signal intensities, indicating their subsequent release to some extent. However, seven days after the removal, depositions of Eu, Gd, and Tb were still present in the same areas of the leaves as before, showing that complete elimination was not achieved after this period of time. Overall, more Eu was present in the leaves compared to Gd and Tb, which can be explained by the high stability of the Eu-DOTA complex, potentially leading to a higher transport rate into the leaves, whereas TbCl 3 and Gd-DTPA-BMA could interact with the roots, reducing their mobility., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Soil salinity impairs plant growth reducing crop productivity. Toxic accumulation of sodium ions is counteracted by the Salt Overly Sensitive (SOS) pathway for Na + extrusion, comprising the Na + transporter SOS1, the kinase SOS2, and SOS3 as one of several Calcineurin-B-like (CBL) Ca 2 + sensors. Here, we report that the receptor-like kinase GSO1/SGN3 activates SOS2, independently of SOS3 binding, by physical interaction and phosphorylation at Thr16. Loss of GSO1 function renders plants salt sensitive and GSO1 is both sufficient and required for activating the SOS2-SOS1 module in yeast and in planta. Salt stress causes the accumulation of GSO1 in two specific and spatially defined areas of the root tip: in the endodermis section undergoing Casparian strip (CS) formation, where it reinforces the CIF-GSO1-SGN1 axis for CS barrier formation; and in the meristem, where it creates the GSO1-SOS2-SOS1 axis for Na + detoxification. Thus, GSO1 simultaneously prevents Na + both from diffusing into the vasculature, and from poisoning unprotected stem cells in the meristem. By protecting the meristem, receptor-like kinase-conferred activation of the SOS2-SOS1 module allows root growth to be maintained in adverse environments., (© 2023 The Authors. Published under the terms of the CC BY NC ND 4.0 license.)

Guard cells control the opening of stomatal pores in the leaf surface, with the use of a network of protein kinases and phosphatases. Loss of function of the CBL-interacting protein kinase 23 (CIPK23) was previously shown to decrease the stomatal conductance, but the molecular mechanisms underlying this response still need to be clarified. CIPK23 was specifically expressed in Arabidopsis guard cells, using an estrogen-inducible system. Stomatal movements were linked to changes in ion channel activity, determined with double-barreled intracellular electrodes in guard cells and with the two-electrode voltage clamp technique in Xenopus oocytes. Expression of the phosphomimetic variant CIPK23 T190D enhanced stomatal opening, while the natural CIPK23 and a kinase-inactive CIPK23 K60N variant did not affect stomatal movements. Overexpression of CIPK23 T190D repressed the activity of S-type anion channels, while their steady-state activity was unchanged by CIPK23 and CIPK23 K60N . We suggest that CIPK23 enhances the stomatal conductance at favorable growth conditions, via the regulation of several ion transport proteins in guard cells. The inhibition of SLAC1-type anion channels is an important facet of this response., (© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.)

Unusually low temperatures caused by global climate change adversely affect rice production. Sensing cold to trigger signal network is a key base for improvement of chilling tolerance trait.  Here, we report that Oryza sativa Calreticulin 3 (OsCRT3) localized at the endoplasmic reticulum (ER) exhibits conformational changes under cold stress, thereby enhancing its interaction with CBL-interacting protein kinase 7 (OsCIPK7) to sense cold. Phenotypic analyses of OsCRT3 knock-out mutants and transgenic overexpression lines demonstrate that OsCRT3 is a positive regulator in chilling tolerance. OsCRT3 localizes at the ER and mediates increases in cytosolic calcium levels under cold stress. Notably, cold stress triggers secondary structural changes of OsCRT3 and enhances its binding affinity with OsCIPK7, which finally boosts its kinase activity. Moreover, Calcineurin B-like protein 7 (OsCBL7) and OsCBL8 interact with OsCIPK7 specifically on the plasma membrane. Taken together, our results thus identify a cold-sensing mechanism that simultaneously conveys cold-induced protein conformational change, enhances kinase activity, and Ca 2+ signal generation to facilitate chilling tolerance in rice., (©2022 The Authors. Published under the terms of the CC BY NC ND 4.0 license.)

Homeostasis of the essential micronutrient manganese (Mn) is crucially determined through availability and uptake efficiency in all organisms. Mn deficiency of plants especially occurs in alkaline and calcareous soils, seriously restricting crop yield. However, the mechanisms underlying the sensing and signaling of Mn availability and conferring regulation of Mn uptake await elucidation. Here, we uncover that Mn depletion triggers spatiotemporally defined long-lasting Ca 2+ oscillations in Arabidopsis roots. These Ca 2+ signals initiate in individual cells, expand, and intensify intercellularly to transform into higher-order multicellular oscillations. Furthermore, through an interaction screen we identified the Ca 2+ -dependent protein kinases CPK21 and CPK23 as Ca 2+ signal-decoding components that bring about translation of these signals into regulation of uptake activity of the high-affinity Mn transporter natural resistance associated macrophage proteins 1 (NRAMP1). Accordingly, a cpk21 / 23 double mutant displays impaired growth and root development under Mn-limiting conditions, while kinase overexpression confers enhanced tolerance to low Mn supply to plants. In addition, we define Thr498 phosphorylation within NRAMP1 as a pivot mechanistically determining NRAMP1 activity, as revealed by biochemical assays and complementation of yeast Mn uptake and Arabidopsis nramp1 mutants. Collectively, these findings delineate the Ca 2+ -CPK21/23-NRAMP1 axis as key for mounting plant Mn homeostasis.

Excessive Na + in soils inhibits plant growth. Here, we report that Na + stress triggers primary calcium signals specifically in a cell group within the root differentiation zone, thus forming a "sodium-sensing niche" in Arabidopsis. The amplitude of this primary calcium signal and the speed of the resulting Ca 2+ wave dose-dependently increase with rising Na + concentrations, thus providing quantitative information about the stress intensity encountered. We also delineate a Ca 2+ -sensing mechanism that measures the stress intensity in order to mount appropriate salt detoxification responses. This is mediated by a Ca 2+ -sensor-switch mechanism, in which the sensors SOS3/CBL4 and CBL8 are activated by distinct Ca 2+ -signal amplitudes. Although the SOS3/CBL4-SOS2/CIPK24-SOS1 axis confers basal salt tolerance, the CBL8-SOS2/CIPK24-SOS1 module becomes additionally activated only in response to severe salt stress. Thus, Ca 2+ -mediated translation of Na + stress intensity into SOS1 Na + /H + antiporter activity facilitates fine tuning of the sodium extrusion capacity for optimized salt-stress tolerance., Competing Interests: Declaration of interests After completion of this work in the laboratory of J.K., K.H.E. became an employee of Yara GmbH & Co. KG, a company that offers products based on calcium as a stress alleviator., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Efficient allocation of the essential nutrient potassium (K + ) is a central determinant of plant ion homeostasis and involves AKT2 K + channels. Here, we characterize four AKT2 K + channels from cotton and report that xylem and phloem expressed GhAKT2bD facilitates K + allocation and that AKT2-silencing impairs plant growth and development. We uncover kinase activity-dependent activation of GhAKT2bD-mediated K + uptake by AtCBL4-GhCIPK1 calcium signalling complexes in HEK293T cells. Moreover, AtCBL4-AtCIPK6 complexes known to convey activation of AtAKT2 in Arabidopsis also activate cotton GhAKT2bD in HEK293T cells. Collectively, these findings reveal an essential role for AKT2 in the source-sink allocation of K + in cotton and identify GhAKT2bD as subject to complex regulation by CBL-CIPK Ca 2+ sensor-kinase complexes., (© 2022 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Manganese (Mn) is an essential micronutrient for all living organisms. However, excess Mn supply that can occur in acid or waterlogged soils has toxic effects on plant physiology and development. Although a variety of Mn transporter families have been characterized, we have only a rudimentary understanding of how these transporters are regulated to uphold and adjust Mn homeostasis in plants. Here, we demonstrate that two calcineurin-B-like proteins, CBL2/3, and their interacting kinases, CIPK3/9/26, are key regulators of plant Mn homeostasis. Arabidopsis mutants lacking CBL2 and 3 or their interacting protein kinases CIPK3/9/26 exhibit remarkably high Mn tolerance. Intriguingly, CIPK3/9/26 interact with and phosphorylate the tonoplast-localized Mn and iron (Fe) transporter MTP8 primarily at Ser35, which is conserved among MTP8 proteins from various species. Mn transport complementation assays in yeast combined with multiple physiological assays indicate that CBL-CIPK-mediated phosphorylation of MTP8 negatively regulates its transport activity from the cytoplasm to the vacuole. Moreover, we show that sequential phosphorylation of MTP8, initially at Ser31/32 by the calcium-dependent protein kinase CPK5 and subsequently at Ser35 by CIPK26, provides an activation/deactivation fine-tuning mechanism for differential regulation of Mn transport. Collectively, our findings define a two-tiered calcium-controlled mechanism for dynamic regulation of Mn homeostasis under conditions of fluctuating Mn supply., (Copyright © 2021 The Author. Published by Elsevier Inc. All rights reserved.)

Adverse variations of abiotic environmental cues that deviate from an optimal range impose stresses to plants. Abiotic stresses severely impede plant physiology and development. Consequently, such stresses dramatically reduce crop yield and negatively impact on ecosystem stability and composition. Physical components of abiotic stresses can be, for example, suboptimal temperature and osmotic perturbations, while representative chemical facets of abiotic stresses can be toxic ions or suboptimal nutrient availability. The sheer complexity of abiotic stresses causes a multitude of diverse components and mechanisms for their sensing and signal transduction. Ca 2+ , as a versatile second messenger, plays multifaceted roles in almost all abiotic stress responses in that, for a certain abiotic stress, Ca 2+ is not only reciprocally connected with its perception, but also multifunctionally ensures subsequent signal transduction. Here, we will focus on salt/osmotic stress and responses to altered nutrient availability as model cases to detail novel insights into the identity of components that link stress perception to Ca 2+ signal formation as well as on new insights into mechanisms of Ca 2+ signal implementation. Finally, we will deduce emerging conceptual consequences of these novel insights and outline arising avenues of future research on the role of Ca 2+ signaling in abiotic stress responses in plants., (© 2022 Institute of Botany, Chinese Academy of Sciences.)