Natural nitrogen isotopic signature reveals deprotonation during ammonium transport across living organisms.
Diphthamide, a post-translationally modified histidine residue of eukaryotic TRANSLATION ELONGATION FACTOR2 (eEF2), is the human host cell-sensitizing target of diphtheria toxin. Diphthamide biosynthesis depends on the 4Fe-4S-cluster protein Dph1 catalyzing the first committed step, as well as Dph2 to Dph7, in yeast and mammals. Here we show that diphthamide modification of eEF2 is conserved inArabidopsis thalianaand requires AtDPH1. Ribosomal \uffe2\uff88\uff921 frameshifting-error rates are increased in Arabidopsisdph1mutants, similar to yeast and mice. Compared to the wild type, shorter roots and smaller rosettes ofdph1mutants result from fewer formed cells. TARGET OF RAPAMYCIN (TOR) kinase activity is attenuated, and autophagy is activated, indph1mutants. Under abiotic stress diphthamide-unmodified eEF2 accumulates in wild-type seedlings, most strongly upon heavy metal excess, which is conserved in human cells. In summary, our results suggest that diphthamide contributes to the functionality of the translational machinery monitored by plants to regulate growth.Drought severely restricts plant production and global warming is further increasing drought stress for crops. Much information reveals the ability of individual microbes affecting plant stress tolerance. However, the effects of emergent bacterial community properties on plant drought tolerance remain largely unexplored. Here, we inoculated Arabidopsis plants in vivo with a four-species bacterial consortium (Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans, and Paenibacillus amylolyticus, termed as SPMX), which is able to synergistically produce more biofilm biomass together than the sum of the four single-strain cultures, to investigate its effects on plant performance and rhizo-microbiota during drought. We found that SPMX remarkably improved Arabidopsis survival post 21-day drought whereas no drought-tolerant effect was observed when subjected to the individual strains, revealing emergent properties of the SPMX consortium as the underlying cause of the induced drought tolerance. The enhanced drought tolerance was associated with sustained chlorophyll content and endogenous abscisic acid (ABA) signaling. Furthermore, our data showed that the addition of SPMX helped to stabilize the diversity and structure of root-associated microbiomes, which potentially benefits plant health under drought. These SPMX-induced changes jointly confer an increased drought tolerance to plants. Our work may inform future efforts to engineer the emergent bacterial community properties to improve plant tolerance to drought. Soil compaction represents a major agronomic challenge, inhibiting root elongation and impacting crop yields. Roots use ethylene to sense soil compaction as the restricted air space causes this gaseous signal to accumulate around root tips. Ethylene inhibits root elongation and promotes radial expansion in compacted soil, but its mechanistic basis remains unclear. Here, we report that ethylene promotes abscisic acid (ABA) biosynthesis and cortical cell radial expansion. Rice mutants of ABA biosynthetic genes had attenuated cortical cell radial expansion in compacted soil, leading to better penetration. Soil compaction-induced ethylene also up-regulates the auxin biosynthesis gene OsYUC8 . Mutants lacking OsYUC8 are better able to penetrate compacted soil. The auxin influx transporter OsAUX1 is also required to mobilize auxin from the root tip to the elongation zone during a root compaction response. Moreover, osaux1 mutants penetrate compacted soil better than the wild-type roots and do not exhibit cortical cell radial expansion. We conclude that ethylene uses auxin and ABA as downstream signals to modify rice root cell elongation and radial expansion, causing root tips to swell and reducing their ability to penetrate compacted soil. Soil salinity presents a dual challenge for plants, involving both osmotic and ionic stress. In response, plants deploy distinct yet interconnected mechanisms to cope with these facets of salinity stress. In this investigation, we observed a substantial overlap in the salt (NaCl)-induced transcriptional responses of Arabidopsis roots with those triggered by osmotic stress or the plant stress hormone abscisic acid (ABA), as anticipated. Notably, a specific cluster of genes responded uniquely to sodium (Na + ) ions and are not regulated by the known monovalent cation sensing mechanism MOCA1 . Surprisingly, expression of sodium-induced genes exhibited a negative correlation with the ABA response and preceded the activation of genes induced by the osmotic stress component of salt. Elevated exogenous ABA levels resulted in the complete abolition of sodium-induced responses. Consistently, the ABA insensitive snrk2.2/2.3 double mutant displayed prolonged sodium-induced gene expression, coupled with increased root cell damage and root swelling under high salinity conditions. Moreover, ABA biosynthesis and signaling mutants were unable to redirect root growth to avoid high sodium concentrations and had increased sodium accumulation in the shoot. In summary, our findings unveil an unexpected and pivotal role for ABA signaling in mitigating cellular damage induced by salinity stress and modulating sodium-induced responses in plant roots. We present unresolved questions in plant abiotic stress biology as posed by 15 research groups with expertise spanning eco-physiology to cell and molecular biology. Common themes of these questions include the need to better understand how plants detect water availability, temperature, salinity, and rising carbon dioxide (CO2) levels; how environmental signals interface with endogenous signaling and development (e.g. circadian clock and flowering time); and how this integrated signaling controls downstream responses (e.g. stomatal regulation, proline metabolism, and growth versus defense balance). The plasma membrane comes up frequently as a site of key signaling and transport events (e.g. mechanosensing and lipid-derived signaling, aquaporins). Adaptation to water extremes and rising CO2 affects hydraulic architecture and transpiration, as well as root and shoot growth and morphology, in ways not fully understood. Environmental adaptation involves tradeoffs that limit ecological distribution and crop resilience in the face of changing and increasingly unpredictable environments. Exploration of plant diversity within and among species can help us know which of these tradeoffs represent fundamental limits and which ones can be circumvented by bringing new trait combinations together. Better defining what constitutes beneficial stress resistance in different contexts and making connections between genes and phenotypes, and between laboratory and field observations, are overarching challenges.Climate oscillations in the Quaternary forced species to major latitudinal or altitudinal range shifts. It has been suggested that adaptation concomitant with range shifts plays key roles in species responses during climate oscillations, but the role of selection for local adaptation to climatic changes remains largely unexplored. Here, we investigated population structure, demographic history and signatures of climate-driven selection based on genome-wide polymorphism data of 141 Japanese Arabidopsis halleri individuals, with European ones as outgroups. Coalescent-based analyses suggested a genetic differentiation between Japanese subpopulations since the Last Glacial Period (LGP), which would have contributed to shaping the current pattern of population structure. Population demographic analysis revealed the population size fluctuations in the LGP, which were particularly prominent since the subpopulations started to diverge (\uffe2\uff88\uffbc50, 000 years ago). The ecological niche modeling predicted the geographic or distribution range shifts from southern coastal regions to northern coastal and mountainous areas, possibly in association with the population size fluctuations. Through genome-wide association analyses of bioclimatic variables and selection scans, we investigated whether climate-associated loci are enriched in the extreme tails of selection scans, and demonstrated the prevailing signatures of selection, particularly toward a warmer climate in southern subpopulations and a drier environment in northern subpopulations, which may have taken place during or after the LGP. Our study highlights the importance of integrating climate associations, selection scans and population demographic analyses for identifying genomic signatures of population-specific adaptation, which would also help us predict the evolutionary responses to future climate changes.Copper (Cu) is a cofactor of around 300 Arabidopsis proteins, including photosynthetic and mitochondrial electron transfer chain enzymes critical for adenosine triphosphate (ATP) production and carbon fixation. Plant acclimation to Cu deficiency requires the transcription factor SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE7 (SPL7). We report that in the wild type (WT) and in the spl7-1 mutant, respiratory electron flux via Cu-dependent cytochrome c oxidase is unaffected under both normal and low-Cu cultivation conditions. Supplementing Cu-deficient medium with exogenous sugar stimulated growth of the WT, but not of spl7 mutants. Instead, these mutants accumulated carbohydrates, including the signaling sugar trehalose 6-phosphate, as well as ATP and NADH, even under normal Cu supply and without sugar supplementation. Delayed spl7-1 development was in agreement with its attenuated sugar responsiveness. Functional TARGET OF RAPAMYCIN and SNF1-RELATED KINASE1 signaling in spl7-1 argued against fundamental defects in these energy-signaling hubs. Sequencing of chromatin immunoprecipitates combined with transcriptome profiling identified direct targets of SPL7-mediated positive regulation, including Fe SUPEROXIDE DISMUTASE1 (FSD1), COPPER-DEFICIENCY-INDUCED TRANSCRIPTION FACTOR1 (CITF1), and the uncharacterized bHLH23 (CITF2), as well as an enriched upstream GTACTRC motif. In summary, transducing energy availability into growth and reproductive development requires the function of SPL7. Our results could help increase crop yields, especially on Cu-deficient soils.Salinity stress constrains lateral root (LR) growth and severely affects plant growth. Auxin signaling regulates LR formation, but the molecular mechanism by which salinity affects root auxin signaling and whether salt induces other pathways that regulate LR development remains unknown. In Arabidopsis thaliana, the auxin-regulated transcription factor LATERAL ORGAN BOUNDARY DOMAIN 16 (LBD16) is an essential player in LR development under control conditions. Here, we show that under high-salt conditions, an alternative pathway regulates LBD16 expression. Salt represses auxin signaling but, in parallel, activates ZINC FINGER OF ARABIDOPSIS THALIANA 6 (ZAT6), a transcriptional activator of LBD16. ZAT6 activates LBD16 expression, thus contributing to downstream cell wall remodeling and promoting LR development under high-salt conditions. Our study thus shows that the integration of auxin-dependent repressive and salt-activated auxin-independent pathways converging on LBD16 modulates root branching under high-salt conditions.Soil salinity is a major contributor to crop yield losses. To improve our understanding of root responses to salinity, we developed and exploited a real-time salt-induced tilting assay. This assay follows root growth upon both gravitropic and salt challenges, revealing that root bending upon tilting is modulated by Na+ ions, but not by osmotic stress. Next, we measured this salt-specific response in 345 natural Arabidopsis (Arabidopsis thaliana) accessions and discovered a genetic locus, encoding the cell wall-modifying enzyme EXTENSIN ARABINOSE DEFICIENT TRANSFERASE (ExAD) that is associated with root bending in the presence of NaCl (hereafter salt). Extensins are a class of structural cell wall glycoproteins known as hydroxyproline (Hyp)-rich glycoproteins, which are posttranslationally modified by O-glycosylation, mostly involving Hyp-arabinosylation. We show that salt-induced ExAD-dependent Hyp-arabinosylation influences root bending responses and cell wall thickness. Roots of exad1 mutant seedlings, which lack Hyp-arabinosylation of extensin, displayed increased thickness of root epidermal cell walls and greater cell wall porosity. They also showed altered gravitropic root bending in salt conditions and a reduced salt-avoidance response. Our results suggest that extensin modification via Hyp-arabinosylation is a unique salt-specific cellular process required for the directional response of roots exposed to salinity.It is a plausible hypothesis that parallel adaptation events to the same environmental challenge should result in genetic changes of similar or identical effects, depending on the underlying fitness landscapes. However, systematic testing of this is scarce. Here we examine this hypothesis in two closely related plant species,Arabidopsis halleriandArabidopsis arenosa, which co-occur at two calamine metalliferous (M) sites harbouring toxic levels of the heavy metals zinc and cadmium. We conduct individual genome resequencing alongside soil elemental analysis for 64 plants from eight populations on M and non-metalliferous (NM) soils, and identify genomic footprints of selection and local adaptation. Selective sweep and environmental association analyses indicate a modest degree of gene as well as functional network convergence, whereby the proximal molecular factors mediating this convergence mostly differ between site pairs and species. Notably, we observe repeated selection on identical single nucleotide polymorphisms in severalA. hallerigenes at two independently colonized M sites. Our data suggest that species-specific metal handling and other biological features could explain a low degree of convergence between species. The parallel establishment of plant populations on calamine M soils involves convergent evolution, which will probably be more pervasive across sites purposely chosen for maximal similarity in soil composition.
This article is part of the theme issue \uffe2\uff80\uff98Convergent evolution in the genomics era: new insights and directions\uffe2\uff80\uff99.Plants growing in proximity to other plants are exposed to a variety of metabolites that these neighbors release into the environment. Some species produce allelochemicals to inhibit growth of neighboring plants, which in turn have evolved ways to detoxify these compounds. In order to understand how the allelochemical-receiving target plants respond to chemically diverse compounds, we performed whole-genome transcriptome analysis ofArabidopsis thalianaexposed to either the benzoxazinoid derivative 2-amino-3H-phenoxazin-3-one (APO) or momilactone B. These two allelochemicals belong to two very different compound classes, benzoxazinoids and diterpenes, respectively, produced by different cereal crop species. Despite their distinct chemical nature, we observed similar molecular responses ofA. thalianato these allelochemicals. In particular, many of the same or closely related genes belonging to the three-phase detoxification pathway were upregulated in both treatments. Further, we observed an overlap between genes upregulated by allelochemicals and those involved in herbicide detoxification. Our findings highlight the overlap in the transcriptional response of a target plant to natural and synthetic phytotoxic compounds and illustrate how herbicide resistance could arise via pathways involved in plant-plant interaction.
", "keywords": ["0301 basic medicine", "2. Zero hunger", "2-amino-3H-phenoxazin-3-one", "0303 health sciences", "Research", "Allelochemical", "Botany", "Arabidopsis", "Benzoxazinoid", "Plants", "Pheromones", "Benzoxazines", "03 medical and health sciences", "Momilactone B", "QK1-989", "Diterpenes", "Diterpene", "Detoxification"]}, "links": [{"href": "https://link.springer.com/content/pdf/10.1186/s12870-022-03780-w.pdf"}, {"href": "https://doi.org/10.1101/2022.02.21.480921"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/BMC%20Plant%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1101/2022.02.21.480921", "name": "item", "description": "10.1101/2022.02.21.480921", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1101/2022.02.21.480921"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-02-22T00:00:00Z"}}, {"id": "10.1101/2022.10.10.511665", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-06-23T16:19:12Z", "type": "Journal Article", "created": "2022-10-13", "title": "A suberized exodermis is required for tomato drought tolerance", "description": "SUMMARYPlant roots integrate environmental signals and developmental programs using exquisite spatiotemporal control. This is apparent in the deposition of suberin, an apoplastic diffusion barrier, which regulates the entry and exit of water, solutes and gases, and is environmentally plastic. Suberin is considered a hallmark of endodermal differentiation, but we find that it is absent in the tomato endodermis during normal development. Instead, suberin is present in the exodermis, a cell type that is absent in the model organismArabidopsis thaliana. Here, we uncover genes driving exodermal suberization and describe its effects on drought responses in tomato, unravelling the similarities and differences with the paradigmatic Arabidopsis endodermis. Cellular resolution imaging, gene expression, and mutant analyses reveal loss of this program from the endodermis, and its co-option in the exodermis. Functional genetic analyses of the tomato MYB92 transcription factor and ASFT enzyme demonstrate the importance of exodermal suberin for a plant water-deficit response. Controlling the degree of exodermal suberization could be a new strategy for breeding climate-resilient plants.During salt stress, the root system architecture of a plant is important for survival. Different accessions ofArabidopsis thalianahave adopted different strategies in remodeling their root architecture during salt stress. Salt induces a multiphase growth response in roots, consisting of a stop phase, quiescent phase, recovery phase and eventually a new level of homeostasis. We explored natural variation in the length of and growth rate during these phases in both main and lateral roots and find that some accessions lack the quiescent phase. Using mathematical models and correlation-based network, allowed us to correlate dynamic traits to overall root architecture and discover that both the main root growth rate during homeostasis and lateral root appearance are the strongest determinants of overall root architecture. In addition, this approach revealed a trade-off between investing in main or lateral root length during salt stress. By studying natural variation in high-resolution temporal root growth using mathematical modeling, we gained new insights in the interactions between dynamic root growth traits and we identified key traits that modulate overall root architecture during salt stress.
Summary statementBy studying natural variation in salt-induced root growth phases inArabidopsis, we show that main root growth rate during homeostasis and lateral root appearance contribute most to root architecture and we reveal a trade-off between investing in main and lateral root growth during salt stress.MicroRNAs (miRNAs) are a class of small non-coding RNAs that play important regulatory roles in plant genomes. While some miRNA genes are deeply conserved, the majority appear to be species-specific, raising the question of how they emerge and integrate into cellular regulatory networks. To address this question, we first performed a detailed annotation of miRNA genes in the closely related Arabidopsis halleri and A. lyrata, then evaluated their phylogenetic conservation across 87 plant species. We then characterized the process by which newly emerged miRNA genes progressively acquire the properties of \uffe2\uff80\uff9ccanonical\uffe2\uff80\uff9d miRNA genes, in terms of size and stability of the hairpin precursor, loading of their cleavage products into Argonaute proteins, and potential to regulate downstream target genes. Analysis of nucleotide polymorphism distribution along the hairpin sequence (stem, mature miRNA, terminal loop) revealed that the selective constraints on recently emerged miRNA genes were initially weak, gradually increasing toward evolutionarily conserved miRNA genes. Our results illustrate the rapid birth-and-death of miRNA genes in plant genomes, and provide a detailed picture of the evolutionary progression toward canonical miRNAs by which a small fraction of de novo formed miRNA genes eventually integrate into \uffe2\uff80\uff9ccore\uffe2\uff80\uff9d biological processes.
Acclimation of root growth is vital for plants to survive salt stress. Halophytes are great examples of plants that thrive even under severe salinity, but their salt tolerance mechanisms, especially those mediated by root responses, are still largely unknown.
We compared root growth responses of the halophyteSchrenkiella parvulawith its glycophytic relative speciesArabidopsis thalianaunder salt stress and performed transcriptomic analysis ofS.\uffc2\uffa0parvularoots to identify possible gene regulatory networks underlying their physiological responses.
Schrenkiella parvularoots do not avoid salt and experience less growth inhibition under salt stress. Salt\uffe2\uff80\uff90induced abscisic acid levels were higher inS.\uffc2\uffa0parvularoots compared with Arabidopsis. Root transcriptomic analysis ofS.\uffc2\uffa0parvularevealed the induction of sugar transporters and genes regulating cell expansion and suberization under salt stress.14C\uffe2\uff80\uff90labeled carbon partitioning analyses showed thatS.\uffc2\uffa0parvulacontinued allocating carbon to roots from shoots under salt stress while carbon barely allocated to Arabidopsis roots. Further physiological investigation revealed thatS.\uffc2\uffa0parvularoots maintained root cell expansion and enhanced suberization under severe salt stress.
In summary, roots ofS.\uffc2\uffa0parvuladeploy multiple physiological and developmental adjustments under salt stress to maintain growth, providing new avenues to improve salt tolerance of plants using root\uffe2\uff80\uff90specific strategies.
Natural nitrogen isotopic signature reveals deprotonation during ammonium transport across living organisms.
Heavy metal\uffe2\uff80\uff90rich toxic soils and ordinary soils are both natural habitats of Arabidopsis halleri, a diploid perennial and obligate outcrosser in the sister clade of the genetic model plant Arabidopsis thaliana. The molecular divergence underlying survival in sharply contrasting environments is unknown. Here we comparatively address metal physiology and transcriptomes of A. halleri originating from the most highly heavy metal\uffe2\uff80\uff90contaminated soil in Europe, Ponte Nossa, Italy (Noss), and from non\uffe2\uff80\uff90metalliferous (NM) soils. Plants from Noss exhibit enhanced hypertolerance and attenuated accumulation of cadmium (Cd), and their transcriptomic Cd responsiveness is decreased, compared to plants of NM soil origin. Among the condition\uffe2\uff80\uff90independent transcriptome characteristics of Noss, the most highly overrepresented functional class of \uffe2\uff80\uff98meiotic cell cycle\uffe2\uff80\uff99 comprises 21 transcripts with elevated abundance in vegetative tissues, in particular Argonaute 9 (AGO9) and the synaptonemal complex transverse filament protein\uffe2\uff80\uff90encoding ZYP1a/b. Increased AGO9 transcript levels in Noss are accompanied by decreased long terminal repeat retrotransposon expression. Similar to Noss, plants from other highly metalliferous sites in Poland and Germany share elevated somatic AGO9 transcript levels in comparison to plants originating from NM soils in their respective geographic regions. Transcript levels of Iron\uffe2\uff80\uff90Regulated Transporter 1 (IRT1) are very low and transcript levels of Heavy Metal ATPase 2 (HMA2) are strongly elevated in Noss, which can account for its altered Cd handling. We conclude that in plants adapted to the most extreme abiotic stress, broadly enhanced functions comprise genes with likely roles in somatic genome integrity maintenance, accompanied by few alterations in stress\uffe2\uff80\uff90specific functional networks.IRON\uffe2\uff80\uff90REGULATED TRANSPORTER1 (IRT1) is the root high\uffe2\uff80\uff90affinity ferrous iron (Fe) uptake system and indispensable for the completion of the life cycle of Arabidopsis thaliana without vigorous Fe supplementation. Here we provide evidence supporting a second role of IRT1 in root\uffe2\uff80\uff90to\uffe2\uff80\uff90shoot partitioning of Fe. We show that irt1 mutants overaccumulate Fe in roots, most prominently in the cortex of the differentiation zone in irt1\uffe2\uff80\uff902, compared to the wild type. Shoots of irt1\uffe2\uff80\uff902 are severely Fe\uffe2\uff80\uff90deficient according to Fe content and marker transcripts, as expected. We generated irt1\uffe2\uff80\uff902 lines producing IRT1 mutant variants carrying single amino\uffe2\uff80\uff90acid substitutions of key residues in transmembrane helices IV and V, Ser206 and His232, which are required for transport activity in yeast. Root short\uffe2\uff80\uff90term 55Fe uptake rates were uninformative concerning IRT1\uffe2\uff80\uff90mediated transport. Overall irt1\uffe2\uff80\uff90like concentrations of the secondary substrate Mn suggested that the transgenic Arabidopsis lines also remain incapable of IRT1\uffe2\uff80\uff90mediated root Fe uptake. Yet, IRT1S206A partially complements rosette dwarfing and leaf chlorosis of irt1\uffe2\uff80\uff902, as well as root\uffe2\uff80\uff90to\uffe2\uff80\uff90shoot Fe partitioning and gene expression defects of irt1\uffe2\uff80\uff902, all of which are fully complemented by wild\uffe2\uff80\uff90type IRT1. Taken together, these results suggest a regulatory function for IRT1 in root\uffe2\uff80\uff90to\uffe2\uff80\uff90shoot Fe partitioning that does not require Fe transport activity of IRT1. Among the genes of which transcript levels are partially dependent on IRT1, we identify MYB DOMAIN PROTEIN10, MYB DOMAIN PROTEIN72 and NICOTIANAMINE SYNTHASE4 as candidates for effecting IRT1\uffe2\uff80\uff90dependent Fe mobilization in roots. Understanding the biological functions of IRT1 will help to improve Fe nutrition and the nutritional quality of agricultural crops. Plant roots exhibit plasticity in their branching patterns to forage efficiently for heterogeneously distributed resources, such as soil water. The xerobranching response represses lateral root formation when roots lose contact with water. Here, we show that xerobranching is regulated by radial movement of the phloem-derived hormone abscisic acid, which disrupts intercellular communication between inner and outer cell layers through plasmodesmata. Closure of these intercellular pores disrupts the inward movement of the hormone signal auxin, blocking lateral root branching. Once root tips regain contact with moisture, the abscisic acid response rapidly attenuates. Our study reveals how roots adapt their branching pattern to heterogeneous soil water conditions by linking changes in hydraulic flux with dynamic hormone redistribution.
The convenient model Arabidopsis thaliana has allowed tremendous advances in plant genetics and physiology, in spite of only being a weed. It has also unveiled the main molecular networks governing, among others, abiotic stress responses. Through the use of the latest genomic tools, Arabidopsis research is nowadays being translated to agronomically interesting crop models such as tomato, but at a lagging pace. Knowledge transfer has been hindered by invariable differences in plant architecture and behaviour, as well as the divergent direct objectives of research in Arabidopsis vs. crops compromise transferability. In this sense, phenotype translation is still a very complex matter. Here, we point out the challenges of \uffe2\uff80\uff9ctranslational phenotyping\uffe2\uff80\uff9d in the case study of drought stress phenotyping in Arabidopsis and tomato. After briefly defining and describing drought stress and survival strategies, we compare drought stress protocols and phenotyping techniques most commonly used in the two species, and discuss their potential to gain insights, which are truly transferable between species. This review is intended to be a starting point for discussion about translational phenotyping approaches among plant scientists, and provides a useful compendium of methods and techniques used in modern phenotyping for this specific plant pair as a case study.
", "keywords": ["Crops", " Agricultural", "0301 basic medicine", "2. Zero hunger", "9. Industry and infrastructure", "Arabidopsis", "Review", "15. Life on land", "6. Clean water", "Droughts", "03 medical and health sciences", "Phenotype", "Solanum lycopersicum", "Gene Expression Regulation", " Plant", "Stress", " Physiological", "Arabidopsis; tomato; phenotyping; drought stress; translational phenotyping; osmotic stress; Dehydration; Arabidopsis thaliana; Solanum lycopersicum; Lycopersicon esculentum", "Plant Proteins"]}, "links": [{"href": "https://air.unimi.it/bitstream/2434/898415/2/genes-11-01011-v3.pdf"}, {"href": "https://iris.unito.it/bitstream/2318/1757296/1/genes-11-01011-v3.pdf"}, {"href": "https://www.mdpi.com/2073-4425/11/9/1011/pdf"}, {"href": "https://doi.org/10.3390/genes11091011"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Genes", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/genes11091011", "name": "item", "description": "10.3390/genes11091011", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/genes11091011"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-08-27T00:00:00Z"}}, {"id": "10.1242/dev.200363", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-06-23T16:20:07Z", "type": "Journal Article", "created": "2022-05-16", "title": "Arabidopsis root responses to salinity depend on pectin modification and cell wall sensing", "description": "ABSTRACTOwing to its detrimental effect on plant growth, salinity is an increasing worldwide problem for agriculture. To understand the molecular mechanisms activated in response to salt in Arabidopsis thaliana, we investigated the Catharanthus roseus receptor-like kinase 1-like family, which contains sensors that were previously shown to be involved in sensing the structural integrity of the cell walls. We found that herk1 the1-4 double mutants, lacking the function of HERKULES1 (HERK1) and combined with a gain-of-function allele of THESEUS1 (THE1), strongly respond to salt application, resulting in an intense activation of stress responses, similarly to plants lacking FERONIA (FER) function. We report that salt triggers pectin methyl esterase (PME) activation and show its requirement for the activation of several salt-dependent responses. Because chemical inhibition of PMEs alleviates these salt-induced responses, we hypothesize a model in which salt directly leads to cell wall modifications through the activation of PMEs. Responses to salt partly require the functionality of FER alone or HERK1/THE1 to attenuate salt effects, highlighting the complexity of the salt-sensing mechanisms that rely on cell wall integrity. Alterations of hydrogen peroxide (H2O2) levels have a profound impact on numerous signaling cascades orchestrating plant growth, development, and stress signaling, including programmed cell death. To expand the repertoire of known molecular mechanisms implicated in H2O2 signaling, we performed a forward chemical screen to identify small molecules that could alleviate the photorespiratory-induced cell death phenotype of Arabidopsisthaliana mutants lacking H2O2-scavenging capacity by peroxisomal catalase2. Here, we report the characterization of pakerine, an m-sulfamoyl benzamide from the sulfonamide family. Pakerine alleviates the cell death phenotype of cat2 mutants exposed to photorespiration-promoting conditions and delays dark-induced senescence in wild-type Arabidopsis leaves. By using a combination of transcriptomics, metabolomics, and affinity purification, we identified abnormal inflorescence meristem 1 (AIM1) as a putative protein target of pakerine. AIM1 is a 3-hydroxyacyl-CoA dehydrogenase involved in fatty acid \u03b2-oxidation that contributes to jasmonic acid (JA) and salicylic acid (SA) biosynthesis. Whereas intact JA biosynthesis was not required for pakerine bioactivity, our results point toward a role for \u03b2-oxidation-dependent SA production in the execution of H2O2-mediated cell death.
Copper (Cu) is a cofactor of around 300 Arabidopsis proteins, including photosynthetic and mitochondrial electron transfer chain enzymes critical for adenosine triphosphate (ATP) production and carbon fixation. Plant acclimation to Cu deficiency requires the transcription factor SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE7 (SPL7). We report that in the wild type (WT) and in the spl7-1 mutant, respiratory electron flux via Cu-dependent cytochrome c oxidase is unaffected under both normal and low-Cu cultivation conditions. Supplementing Cu-deficient medium with exogenous sugar stimulated growth of the WT, but not of spl7 mutants. Instead, these mutants accumulated carbohydrates, including the signaling sugar trehalose 6-phosphate, as well as ATP and NADH, even under normal Cu supply and without sugar supplementation. Delayed spl7-1 development was in agreement with its attenuated sugar responsiveness. Functional TARGET OF RAPAMYCIN and SNF1-RELATED KINASE1 signaling in spl7-1 argued against fundamental defects in these energy-signaling hubs. Sequencing of chromatin immunoprecipitates combined with transcriptome profiling identified direct targets of SPL7-mediated positive regulation, including Fe SUPEROXIDE DISMUTASE1 (FSD1), COPPER-DEFICIENCY-INDUCED TRANSCRIPTION FACTOR1 (CITF1), and the uncharacterized bHLH23 (CITF2), as well as an enriched upstream GTACTRC motif. In summary, transducing energy availability into growth and reproductive development requires the function of SPL7. Our results could help increase crop yields, especially on Cu-deficient soils.Copper (Cu) is a cofactor of around 300 Arabidopsis proteins, including photosynthetic and mitochondrial electron transfer chain enzymes critical for adenosine triphosphate (ATP) production and carbon fixation. Plant acclimation to Cu deficiency requires the transcription factor SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE7 (SPL7). We report that in the wild type (WT) and in the spl7-1 mutant, respiratory electron flux via Cu-dependent cytochrome c oxidase is unaffected under both normal and low-Cu cultivation conditions. Supplementing Cu-deficient medium with exogenous sugar stimulated growth of the WT, but not of spl7 mutants. Instead, these mutants accumulated carbohydrates, including the signaling sugar trehalose 6-phosphate, as well as ATP and NADH, even under normal Cu supply and without sugar supplementation. Delayed spl7-1 development was in agreement with its attenuated sugar responsiveness. Functional TARGET OF RAPAMYCIN and SNF1-RELATED KINASE1 signaling in spl7-1 argued against fundamental defects in these energy-signaling hubs. Sequencing of chromatin immunoprecipitates combined with transcriptome profiling identified direct targets of SPL7-mediated positive regulation, including Fe SUPEROXIDE DISMUTASE1 (FSD1), COPPER-DEFICIENCY-INDUCED TRANSCRIPTION FACTOR1 (CITF1), and the uncharacterized bHLH23 (CITF2), as well as an enriched upstream GTACTRC motif. In summary, transducing energy availability into growth and reproductive development requires the function of SPL7. Our results could help increase crop yields, especially on Cu-deficient soils.Heavy metal\uffe2\uff80\uff90rich toxic soils and ordinary soils are both natural habitats of Arabidopsis halleri, a diploid perennial and obligate outcrosser in the sister clade of the genetic model plant Arabidopsis thaliana. The molecular divergence underlying survival in sharply contrasting environments is unknown. Here we comparatively address metal physiology and transcriptomes of A. halleri originating from the most highly heavy metal\uffe2\uff80\uff90contaminated soil in Europe, Ponte Nossa, Italy (Noss), and from non\uffe2\uff80\uff90metalliferous (NM) soils. Plants from Noss exhibit enhanced hypertolerance and attenuated accumulation of cadmium (Cd), and their transcriptomic Cd responsiveness is decreased, compared to plants of NM soil origin. Among the condition\uffe2\uff80\uff90independent transcriptome characteristics of Noss, the most highly overrepresented functional class of \uffe2\uff80\uff98meiotic cell cycle\uffe2\uff80\uff99 comprises 21 transcripts with elevated abundance in vegetative tissues, in particular Argonaute 9 (AGO9) and the synaptonemal complex transverse filament protein\uffe2\uff80\uff90encoding ZYP1a/b. Increased AGO9 transcript levels in Noss are accompanied by decreased long terminal repeat retrotransposon expression. Similar to Noss, plants from other highly metalliferous sites in Poland and Germany share elevated somatic AGO9 transcript levels in comparison to plants originating from NM soils in their respective geographic regions. Transcript levels of Iron\uffe2\uff80\uff90Regulated Transporter 1 (IRT1) are very low and transcript levels of Heavy Metal ATPase 2 (HMA2) are strongly elevated in Noss, which can account for its altered Cd handling. We conclude that in plants adapted to the most extreme abiotic stress, broadly enhanced functions comprise genes with likely roles in somatic genome integrity maintenance, accompanied by few alterations in stress\uffe2\uff80\uff90specific functional networks.Diphthamide, a post-translationally modified histidine residue of eukaryotic TRANSLATION ELONGATION FACTOR2 (eEF2), is the human host cell-sensitizing target of diphtheria toxin. Diphthamide biosynthesis depends on the 4Fe-4S-cluster protein Dph1 catalyzing the first committed step, as well as Dph2 to Dph7, in yeast and mammals. Here we show that diphthamide modification of eEF2 is conserved inArabidopsis thalianaand requires AtDPH1. Ribosomal \uffe2\uff88\uff921 frameshifting-error rates are increased in Arabidopsisdph1mutants, similar to yeast and mice. Compared to the wild type, shorter roots and smaller rosettes ofdph1mutants result from fewer formed cells. TARGET OF RAPAMYCIN (TOR) kinase activity is attenuated, and autophagy is activated, indph1mutants. Under abiotic stress diphthamide-unmodified eEF2 accumulates in wild-type seedlings, most strongly upon heavy metal excess, which is conserved in human cells. In summary, our results suggest that diphthamide contributes to the functionality of the translational machinery monitored by plants to regulate growth. Heavy metal\uffe2\uff80\uff90rich toxic soils and ordinary soils are both natural habitats of Arabidopsis halleri , a diploid perennial and obligate outcrosser in the sister clade of the genetic model plant Arabidopsis thaliana . The molecular divergence underlying survival in sharply contrasting environments is unknown. Here we comparatively address metal physiology and transcriptomes of A. halleri originating from the most highly heavy metal\uffe2\uff80\uff90contaminated soil in Europe, Ponte Nossa, Italy (Noss), and from non\uffe2\uff80\uff90metalliferous (NM) soils. Plants from Noss exhibit enhanced hypertolerance and attenuated accumulation of cadmium (Cd), and their transcriptomic Cd responsiveness is decreased, compared to plants of NM soil origin. Among the condition\uffe2\uff80\uff90independent transcriptome characteristics of Noss, the most highly overrepresented functional class of \uffe2\uff80\uff98meiotic cell cycle\uffe2\uff80\uff99 comprises 21 transcripts with elevated abundance in vegetative tissues, in particular Argonaute 9 ( AGO9 ) and the synaptonemal complex transverse filament protein\uffe2\uff80\uff90encoding ZYP1a/b . Increased AGO9 transcript levels in Noss are accompanied by decreased long terminal repeat retrotransposon expression. Similar to Noss, plants from other highly metalliferous sites in Poland and Germany share elevated somatic AGO9 transcript levels in comparison to plants originating from NM soils in their respective geographic regions. Transcript levels of Iron\uffe2\uff80\uff90Regulated Transporter 1 ( IRT1 ) are very low and transcript levels of Heavy Metal ATPase 2 ( HMA2 ) are strongly elevated in Noss, which can account for its altered Cd handling. We conclude that in plants adapted to the most extreme abiotic stress, broadly enhanced functions comprise genes with likely roles in somatic genome integrity maintenance, accompanied by few alterations in stress\uffe2\uff80\uff90specific functional networks. 108 \u2009CFUs\u2009ml-1 ), suggesting that SA187 is able to evade or suppress the plant defence system at lower titres. Although SA187 flagellin epitopes are recognized by the FLS2 receptor, SA187-triggered salt tolerance functions independently of the FLS2 system. In contrast, overexpression of the chitin receptor components LYK4 and LYK5 compromised the beneficial effect of SA187 on Arabidopsis, while it was enhanced in lyk4 mutant plants. Transcriptome analysis revealed that the role of LYK4 is intertwined with a function in remodelling defence responses with growth and root developmental processes. LYK4 interferes with modification of plant ethylene homeostasis by Enterobacter SA187 to boost salt stress resistance. Collectively, these results contribute to unlock the crosstalk between components of the plant immune system and beneficial microbes and point to a new role for the Lys-motif receptor LYK4 in beneficial plant-microbe interaction.", "keywords": ["580", "[SDV] Life Sciences [q-bio]", "570", "Arabidopsis Proteins", "[SDV]Life Sciences [q-bio]", "Arabidopsis", "Enterobacter", "Plant Immunity", "Salt Tolerance", "Microbiology", "Ecology", " Evolution", " Behavior and Systematics", "Research Articles"]}, "links": [{"href": "https://air.unimi.it/bitstream/2434/895359/2/Environmental%20Microbiology%20-%202021%20-%20Rolli%20-%20The%20Lys%e2%80%90motif%20receptor%20LYK4%20mediates%20Enterobacter%20sp%20%20SA187%20triggered%20salt.pdf"}, {"href": "https://doi.org/10754/675134"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Environmental%20microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10754/675134", "name": "item", "description": "10754/675134", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10754/675134"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-01-01T00:00:00Z"}}, {"id": "10919/117635", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-06-23T16:25:54Z", "type": "Journal Article", "created": "2022-10-13", "title": "A suberized exodermis is required for tomato drought tolerance", "description": "SUMMARY
Plant roots integrate environmental signals and developmental programs using exquisite spatiotemporal control. This is apparent in the deposition of suberin, an apoplastic diffusion barrier, which regulates the entry and exit of water, solutes and gases, and is environmentally plastic. Suberin is considered a hallmark of endodermal differentiation, but we find that it is absent in the tomato endodermis during normal development. Instead, suberin is present in the exodermis, a cell type that is absent in the model organismArabidopsis thaliana. Here, we uncover genes driving exodermal suberization and describe its effects on drought responses in tomato, unravelling the similarities and differences with the paradigmatic Arabidopsis endodermis. Cellular resolution imaging, gene expression, and mutant analyses reveal loss of this program from the endodermis, and its co-option in the exodermis. Functional genetic analyses of the tomato MYB92 transcription factor and ASFT enzyme demonstrate the importance of exodermal suberin for a plant water-deficit response. Controlling the degree of exodermal suberization could be a new strategy for breeding climate-resilient plants. Soil compaction represents a major agronomic challenge, inhibiting root elongation and impacting crop yields. Roots use ethylene to sense soil compaction as the restricted air space causes this gaseous signal to accumulate around root tips. Ethylene inhibits root elongation and promotes radial expansion in compacted soil, but its mechanistic basis remains unclear. Here, we report that ethylene promotes abscisic acid (ABA) biosynthesis and cortical cell radial expansion. Rice mutants of ABA biosynthetic genes had attenuated cortical cell radial expansion in compacted soil, leading to better penetration. Soil compaction-induced ethylene also up-regulates the auxin biosynthesis gene OsYUC8 . Mutants lacking OsYUC8 are better able to penetrate compacted soil. The auxin influx transporter OsAUX1 is also required to mobilize auxin from the root tip to the elongation zone during a root compaction response. Moreover, osaux1 mutants penetrate compacted soil better than the wild-type roots and do not exhibit cortical cell radial expansion. We conclude that ethylene uses auxin and ABA as downstream signals to modify rice root cell elongation and radial expansion, causing root tips to swell and reducing their ability to penetrate compacted soil. Soil salinity is a major contributor to crop yield losses. To improve our understanding of root responses to salinity, we developed and exploited a real-time salt-induced tilting assay. This assay follows root growth upon both gravitropic and salt challenges, revealing that root bending upon tilting is modulated by Na+ ions, but not by osmotic stress. Next, we measured this salt-specific response in 345 natural Arabidopsis (Arabidopsis thaliana) accessions and discovered a genetic locus, encoding the cell wall-modifying enzyme EXTENSIN ARABINOSE DEFICIENT TRANSFERASE (ExAD) that is associated with root bending in the presence of NaCl (hereafter salt). Extensins are a class of structural cell wall glycoproteins known as hydroxyproline (Hyp)-rich glycoproteins, which are posttranslationally modified by O-glycosylation, mostly involving Hyp-arabinosylation. We show that salt-induced ExAD-dependent Hyp-arabinosylation influences root bending responses and cell wall thickness. Roots of exad1 mutant seedlings, which lack Hyp-arabinosylation of extensin, displayed increased thickness of root epidermal cell walls and greater cell wall porosity. They also showed altered gravitropic root bending in salt conditions and a reduced salt-avoidance response. Our results suggest that extensin modification via Hyp-arabinosylation is a unique salt-specific cellular process required for the directional response of roots exposed to salinity.IRON\uffe2\uff80\uff90REGULATED TRANSPORTER1 (IRT1) is the root high\uffe2\uff80\uff90affinity ferrous iron (Fe) uptake system and indispensable for the completion of the life cycle of Arabidopsis thaliana without vigorous Fe supplementation. Here we provide evidence supporting a second role of IRT1 in root\uffe2\uff80\uff90to\uffe2\uff80\uff90shoot partitioning of Fe. We show that irt1 mutants overaccumulate Fe in roots, most prominently in the cortex of the differentiation zone in irt1\uffe2\uff80\uff902, compared to the wild type. Shoots of irt1\uffe2\uff80\uff902 are severely Fe\uffe2\uff80\uff90deficient according to Fe content and marker transcripts, as expected. We generated irt1\uffe2\uff80\uff902 lines producing IRT1 mutant variants carrying single amino\uffe2\uff80\uff90acid substitutions of key residues in transmembrane helices IV and V, Ser206 and His232, which are required for transport activity in yeast. Root short\uffe2\uff80\uff90term 55Fe uptake rates were uninformative concerning IRT1\uffe2\uff80\uff90mediated transport. Overall irt1\uffe2\uff80\uff90like concentrations of the secondary substrate Mn suggested that the transgenic Arabidopsis lines also remain incapable of IRT1\uffe2\uff80\uff90mediated root Fe uptake. Yet, IRT1S206A partially complements rosette dwarfing and leaf chlorosis of irt1\uffe2\uff80\uff902, as well as root\uffe2\uff80\uff90to\uffe2\uff80\uff90shoot Fe partitioning and gene expression defects of irt1\uffe2\uff80\uff902, all of which are fully complemented by wild\uffe2\uff80\uff90type IRT1. Taken together, these results suggest a regulatory function for IRT1 in root\uffe2\uff80\uff90to\uffe2\uff80\uff90shoot Fe partitioning that does not require Fe transport activity of IRT1. Among the genes of which transcript levels are partially dependent on IRT1, we identify MYB DOMAIN PROTEIN10, MYB DOMAIN PROTEIN72 and NICOTIANAMINE SYNTHASE4 as candidates for effecting IRT1\uffe2\uff80\uff90dependent Fe mobilization in roots. Understanding the biological functions of IRT1 will help to improve Fe nutrition and the nutritional quality of agricultural crops. Alterations of hydrogen peroxide (H2O2) levels have a profound impact on numerous signaling cascades orchestrating plant growth, development, and stress signaling, including programmed cell death. To expand the repertoire of known molecular mechanisms implicated in H2O2 signaling, we performed a forward chemical screen to identify small molecules that could alleviate the photorespiratory-induced cell death phenotype of Arabidopsisthaliana mutants lacking H2O2-scavenging capacity by peroxisomal catalase2. Here, we report the characterization of pakerine, an m-sulfamoyl benzamide from the sulfonamide family. Pakerine alleviates the cell death phenotype of cat2 mutants exposed to photorespiration-promoting conditions and delays dark-induced senescence in wild-type Arabidopsis leaves. By using a combination of transcriptomics, metabolomics, and affinity purification, we identified abnormal inflorescence meristem 1 (AIM1) as a putative protein target of pakerine. AIM1 is a 3-hydroxyacyl-CoA dehydrogenase involved in fatty acid \u03b2-oxidation that contributes to jasmonic acid (JA) and salicylic acid (SA) biosynthesis. Whereas intact JA biosynthesis was not required for pakerine bioactivity, our results point toward a role for \u03b2-oxidation-dependent SA production in the execution of H2O2-mediated cell death.
It is a plausible hypothesis that parallel adaptation events to the same environmental challenge should result in genetic changes of similar or identical effects, depending on the underlying fitness landscapes. However, systematic testing of this is scarce. Here we examine this hypothesis in two closely related plant species, Arabidopsis halleri and Arabidopsis arenosa , which co-occur at two calamine metalliferous (M) sites harbouring toxic levels of the heavy metals zinc and cadmium. We conduct individual genome resequencing alongside soil elemental analysis for 64 plants from eight populations on M and non-metalliferous (NM) soils, and identify genomic footprints of selection and local adaptation. Selective sweep and environmental association analyses indicate a modest degree of gene as well as functional network convergence, whereby the proximal molecular factors mediating this convergence mostly differ between site pairs and species. Notably, we observe repeated selection on identical single nucleotide polymorphisms in several A. halleri genes at two independently colonized M sites. Our data suggest that species-specific metal handling and other biological features could explain a low degree of convergence between species. The parallel establishment of plant populations on calamine M soils involves convergent evolution, which will probably be more pervasive across sites purposely chosen for maximal similarity in soil composition.
This article is part of the theme issue \uffe2\uff80\uff98Convergent evolution in the genomics era: new insights and directions\uffe2\uff80\uff99.