Molecular Plant
○ Elsevier BV
Preprints posted in the last 30 days, ranked by how well they match Molecular Plant's content profile, based on 39 papers previously published here. The average preprint has a 0.04% match score for this journal, so anything above that is already an above-average fit.
Zhang, H.; Aizezi, Y.; Bessho-Uehara, K.; Chaudhary, A.; Trinh, C. S.; Xu, S.-L.; Wang, Z.-Y.
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Sugar is both an essential energy source and the major substrate for cell wall biosynthesis during plant growth, yet how growth-promoting hormones regulate sugar synthesis remains unclear. Here, we show that the brassinosteroids (BRs) promote gluconeogenic and photosynthetic sugar synthesis by activating phosphoenolpyruvate carboxykinase (PCK), which catalyzes the conversion of oxaloacetate to phosphoenolpyruvate, a central step in primary metabolism. Arabidopsis BR-deficient mutants display reduced PCK1 activity and elevated phosphorylation at conserved Ser-62 and Thr-66 residues. BR treatment induces PCK1 dephosphorylation and activation, whereas the GSK3-like kinase BIN2 phosphorylates these sites, altering quaternary structure and inhibiting PCK1. Phospho-blocking mutations of Ser-62/Thr-66 confer BR-independent PCK1 activity and enhance seedling growth, while phosphomimetic mutations reduce PCK1 activity and impair seedling growth and establishment. BR also promotes PCK dephosphorylation and activation in photosynthetic leaves of maize and sorghum. Our study demonstrates that BR regulates primary metabolism via GSK3/BIN2-mediated phosphorylation of PCK, thereby promoting gluconeogenesis and photosynthesis.
Wu, Y.-N.; Lu, J.-Y.; Gao, Y.; Li, S.; Xiong, F.; Zhang, Y.
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Ribosome biogenesis is critical for plant development and environmental responses. A large number of ribosomal proteins (RPs) and ribosomal biogenesis factors (RBFs) are required for ribosome biogenesis, many of which remain uncharacterized in plants. We report here the identification of Arabidopsis RBF FAN and its interacting partner FAN-INTERACTING PROTEIN 1 (FIP1). As their human and yeast orthologues, FAN-FIP1 interact. Both FAN and FIP1 participate in the processing of pre-rRNAs. Functional loss of FAN or FIP1 knock-down results in developmental retardation and hypersensitivity to heat stresses. We demonstrate that FAN-FIP1 positively mediates brassinosteroid (BR) signaling by ensuring the translation efficiency of the BR receptor-coding gene BRASSINOSTEROID INSENSITIVE 1 (BRI1) through the presence of its upstream open reading frame (uORF). Importantly, BR signaling positively mediates the processing of pre-rRNAs, which may be critical not only for development but also for heat tolerance.
Prasetyaningrum, P.; Crisostomo, V. H.; Reimers, M.; Krueger, S.; Hiltbrunner, A.
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Plants detect neighbours through a reduced red-to-far-red ratio (R:FR), triggering elongation growth that reduces crop yield. Although Gibberellin (GA) is required for the neighbour-proximity (NP) elongation response, bioactive GA levels do not increase sufficiently to account for elongation magnitude, suggesting GA sensitivity as an additional regulated variable. Here, we show that GID1C, one of three Arabidopsis GA receptors, is the primary GA receptor involved in NP-induced elongation. GID1C protein accumulates selectively in hypocotyls and root tips under low R:FR without an increase in bioactive GA. The gid1c mutant shows a reduced elongation response that exogenous GA treatment cannot rescue. Transcriptome profiling reveals that GID1C controls 86% of the NP-responsive transcriptome, including genes for cell growth, division, and transcriptional regulation. Hub analysis identifies ICE1 as a GID1C-repressed transcriptional brake. ICE1 transcript is suppressed under low R:FR in a GID1C-dependent manner, and a phosphorylation-resistant ICE1 allele blocks NP-induced elongation. Together, these findings establish GA perception as an additional regulatory layer in NP, with subfunctionalisation among GID1 paralogs shaping the response to neighbouring plants.
Zhao, F.; Zhao, J.; Zhao, F.; Bai, S.; Wu, Y.; Zhu, R.
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Pigmented rice landraces are prized for their anthocyanin-accumulating pericarp, yet the repeat-rich regulatory alleles that govern pigmentation are poorly resolved in draft assemblies. Here we report a gap-free, telomere-to-telomere (T2T) genome of Mojiang purple rice (ZN65), a glutinous purple-pericarp Hani landrace from Yunnan, China. The 395.1-Mb assembly comprises twelve gap-free chromosomes with all 24 telomeres, all 12 centromeres and the 45S/5S ribosomal DNA arrays resolved (contig N50 32.35 Mb; Merqury QV 53.6; 99.6% BUSCO); we annotated 42,090 protein-coding genes, with transposable elements occupying 56.6% of the genome. Against the japonica reference Nipponbare we identified 1,045,956 single-nucleotide variants, 121 inversions and 449 translocations; ZN65 is larger on every chromosome (~22 Mb cumulative excess), reflecting lineage-specific retrotransposon expansion (26.9 Mb of LTR/Gypsy within 73.3 Mb of ZN65-specific sequence), and falls in the indica group. The flavonoid pathway is complete and copy-number-conserved (100 genes), so pigmentation maps to regulators: OsC1/Kala3 is conserved, whereas Kala4/OsB2, Kala1/OsDFR and Rc each carry transposon-associated structural variation. ZN65 encodes a functional pigmentation-allele complement - most diagnostically a full-length Rc with an intact bHLH domain, unlike the truncated rc allele of white Nipponbare. At Kala4/OsB2, ZN65 carries a long-read-validated retrotransposon architecture, including a ZN65-specific proximal-promoter insertion absent across a seven-genome panel - a candidate, lineage-specific realization of the black-rice gain-of-function mechanism, distinct from the canonical tandem-duplication allele. This T2T resource and its pigmentation-locus haplotypes provide a foundation for the functional study and molecular breeding of pigmented rice.
Hong, K.;Kim, J.;Sung, S.;Song, J.
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Polycomb Repressive Complex 2 (PRC2) is a histone H3K27 methyltransferase that represses gene expression. Arabidopsis thaliana (A. thaliana) has several different PRC2 isoforms that are functionally distinct during the life cycle of the plants. However, their biochemical and structural characteristics have not been investigated. Here, we biochemically characterized PRC2 isoforms having different catalytic subunits: SWNINGER (SWN; PRC2 SWN ) and CURLY LEAF (CLF; PRC2 CLF ). Interestingly, PRC2 SWN showed much lower activity than PRC2 CLF . In addition, PRC2 SWN methylates histone H3K27 in mono and di-methylation, while PRC2 CLF shows robust tri-methylase activity. We also determined the cryo-electron microscopy (cryo-EM) structures of PRC2 SWN and PRC2 CLF , revealing that the substrate binding pocket of the SWN SET domain is blocked by a loop in the pre-SET domain, functioning as an auto-inhibitory loop, while that of the CLF SET domain is freely accessible. Introduction of CLF-like mutations in the auto-inhibitory loop in SWN enhances PRC2 SWN activity. Furthermore, structure-guided in planta analysis shows that a CLF-mimetic SWN mutant rescues the CLF knockout phenotype. Our work provides structural and molecular insights into the isoform-specific regulatory mechanism of plant PRC2.
Anzardi Ruffino, L.; Suarez, J.; Yanez Santos, A. M.; Lobatto, V. L.; Mary, V. S.; Theumer, M. G.; Mesquida Nardini, M. C.; Cecchini, N. M.; Lascano, H. R.; Lescano Lopez I, I.
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Elevated temperatures compromise plant immunity and increase susceptibility to bacterial pathogens through extensive reprogramming of hormone signaling pathways. Although autophagy contributes to both stress adaptation and pathogen defense, its role in hormone-dependent immune regulation under warm conditions remains unclear. Here, we investigated the contribution of NBR1 (NEIGHBOR OF BRCA1 GENE 1)-mediated selective autophagy to Arabidopsis immunity against Pseudomonas cannabina pv. alisalensis at elevated temperature. Bacterial infection under warming enhanced autophagic flux and promoted NBR1 turnover, indicating increased autophagic activity. Analysis of atg5 and nbr1 mutants, and NBR1-overexpressing lines, demonstrated that both core autophagy and NBR1-mediated selective autophagy contribute to bacterial immunity under warm conditions. Hormone and gene expression analyses indicated that NBR1 negatively regulates abscisic acid (ABA)-associated transcriptional responses during infection, while salicylic acid signaling was largely unaffected. Mechanistically, NBR1 physically associated with the ABA-responsive transcription factor ABI5 (ABA INSENSITIVE 5) and promoted its autophagy-dependent turnover in planta. ABI5 turnover was strongly reduced under warm conditions, leading to its accumulation in nbr1 and atg5 plants. Consistent with a functional role for ABI5 in this phenotype, genetic disruption of ABI5 largely reversed the increased susceptibility of nbr1 mutants at elevated temperature, whereas ABI5 overexpression increased susceptibility to bacterial infection. Together, our results identify NBR1-mediated selective autophagy as a regulatory mechanism that restrains ABA-associated susceptibility through the autophagy-dependent turnover of ABI5. These findings reveal a previously unrecognized connection between selective autophagy and ABA-dependent immune regulation and identify NBR1-mediated ABI5 turnover as a temperature-dependent mechanism that prevents stronger bacterial susceptibility under warm conditions.
Percio, F.;Pagano-Marquez, R.;Espino, A.;Colin, L.;Luo, J.;Pérez-Sancho, J.;Toth, R.;DeFalco, T.;Zhou, J.;Macho, A.;Zipfel, C.;Rubio, L.;Persson, S.;Amorim-Silva, V.;Botella, M.
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Cellulose, a central structural component of plant cell walls, is produced by cellulose synthase complexes (CSCs) at the plasma membrane. Salinity stress is particularly damaging to cellulose biosynthesis, and therefore, plants have developed adaptive mechanisms to cope with these conditions. TETRATRICOPEPTIDE THIOREDOXIN-LIKE (TTL) proteins are essential for growth under salt stress and show a salt-dependent association with CSCs through an as-yet unknown mechanism. Here, we identify a phosphorylation-dependent regulatory mechanism linking salt stress signaling to cellulose biosynthesis through the coordinated action of TTL3 and the receptor-like cytoplasmic kinase BOTRYTIS-INDUCED KINASE 1 (BIK1). Phosphorylation of Serine 93 in the N-terminal intrinsically disordered region of TTL3 controls its localization, retaining it in the cytosol, while dephosphorylation promotes association with CSCs at the plasma membrane. Biochemical and genetic analysis identified BIK1 as the kinase responsible for TTL3-S93 phosphorylation, with bik1 mutants phenocopying the phosphoablative TTL3S93A in vivo. Transcriptomic analyses reveal a strong overlap of differentially expressed genes between bik1 and a cellulose-deficient mutant, supporting a broader role for BIK1 in cell wall regulation. Notably, TTL proteins do not appear to be involved in the assayed canonical immune responses, suggesting pathway specificity downstream of BIK1. Together, these findings define a signaling module that connects salt stress perception to CSCs regulation and establish BIK1-dependent TTL3 phosphorylation as a molecular switch for maintaining cell wall integrity under abiotic stress.
Brykov, V.; Huffer, L.; Medvecka, E.; Korec Podmanicka, T.; Kocourkova, D.; Levenets, L.; Harant, K.; Schmidtova, M.; Dubey, S. M.; Krtkova, J.; Kulich, I.; Pleskot, R.; Oulehlova, D.; Fendrych, M.
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The phytohormone auxin is a central coordinator of plant growth and development. Besides its canonical effect on gene transcription1,2, auxin triggers an ultra-rapid calcium ion influx that initiates the root gravitropic response3. The nature of the so-called rapid auxin pathway connecting the AFB1 auxin receptor3,4 and plasma membrane calcium channels remained unknown. Here, we show that auxin induces the direct interaction of the AFB1 receptor with the CNGC14 calcium channel. As the AFB1 receptor is independent of the ubiquitin ligase complex5, the auxin-induced interaction translates into relocalization of the receptor to the plasma membrane. We identify the interaction interface and provide evidence that the docking of the receptor to the channel complex activates Ca2+ influx and triggers growth inhibition. These findings position a calcium channel as an unprecedented component of the AFB1 auxin receptor complex. The ligand-dependent localization shift of a TIR1/AFB family receptor represents a novel paradigm in signal transduction and opens the possibility of unforeseen branches of auxin signaling pathways.
Shazadee, H.; Edwards, T.; Levesque-Lemay, M.; Zheng, C.; Ens, J.; Pozniak, C. J.; You, F. M.; Cloutier, S.
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Aegilops species are the closest wild relatives of wheat and an important reservoir of genetic diversity for its improvement. Despite their potential, many Aegilops genomes remain poorly characterized. Here we present high-quality assemblies of 18 diploid, tetraploid, and hexaploid Aegilops genomes, which, along with the previously published genomes, complete the production of reference assemblies for all 25 genomes in this genus. Assembly sizes ranged from 5.24 Gb in diploids to 12.65 Gb in hexaploids, with scaffold N50 values up to 749.2 Mb. Gene annotation identified 53,035-156,779 protein-coding genes, of which 21,865-60,490 were classified as high-confidence. Orthogroup-based pangenome analysis across the 25 Aegilops genomes identified 80,521 orthogroups, including 15,809 core, 61,735 dispensable, and 2,977 species-specific orthogroups, highlighting substantial gene content variation among genomes. Phylogenetic analysis of 63 Triticum and Aegilops genomes/subgenomes based on near single-copy orthologs defines the phylogenetic relationships within the Triticum/Aegilops complex and confirms diploid progenitors of polyploid lineages. Ae. mutica (T) and Ae. speltoides (S) belong to the B lineage while the remaining Sitopsis grouped within the D lineage. Structural variation analyses using diploid progenitors as references revealed extensive large-scale rearrangements following polyploidization, emphasizing the dynamics of their evolution. Transposable element (TE) annotation further highlighted subgenome-specific TE expansions and contractions, providing insights into the mechanisms shaping genome structure after polyploidization. Collectively, these genomic resources provide a comprehensive framework for exploring Aegilops diversity, understanding polyploid evolution, and accelerating wheat improvement.
Tsinyk, M.; Hlavackova, K.; Ovecka, M.; Rehak, J.; Sojka, J.; Spundova, M.; Kucerova, Z.; Samaj, J.; Takac, T.; Dvorak, P.
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Copper (Cu) is an essential micronutrient whose bioavailability is strongly affected by soil physicochemical properties. During evolution, plants have developed mechanisms to flexibly adjust their metabolism to Cu status. Superoxide dismutases (SODs), including Cu/ZnSOD1 (CSD1) and FeSOD1 (FSD1), are key antioxidant enzymes regulated in Cu dependent manner in Arabidopsis thaliana. Examination of CSD1 cellular distribution and activity revealed that CSD1 is a nuclear and cytosolic SOD whose abundance and activity respond to Cu availability inversely to FSD1. Combined microscopic and biochemical analyses of Cu-dependent dynamics revealed that, unlike FSD1, CSD1 localization in guard cells (GCs) remains independent of Cu availability. CSD1 escapes miR398-mediated regulation in GCs through a cell type-specific splice variant (CSD1.2) that carries an altered miR398-binding site. In silico analyses indicate that this mechanism is also present in crop species. Functionally, the csd1 mutant showed reduced sensitivity to abscisic acid (ABA)-induced stomatal closure, a phenotype rescued by reintroducing CSD1. Biochemical and reactive oxygen species (ROS) level analyses indicate that CSD1.2 most likely acts independently of its canonical enzymatic activity in GCs and functions upstream of the ROS burst in the ABA signaling pathway. Together, we present a novel, cell-type-specific mechanism that safeguards ABA-driven stomatal closure under fluctuating Cu supply.
Ortner-Krause, F.; Goliasse, M.; Gitau, J.; Johary, A.; Rahmdani, F.; Joly-Lopez, Z.
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Drought increasingly constrains global rice productivity, yet how water deficit remodels cis-regulatory activity in plants remains poorly resolved. Here we used precision run-on sequencing (PRO-seq) to profile nascent transcription in rice leaves under well-watered and drought conditions and mapped transcription-initiation regions with the tool dREG, which detects genome-wide peaks of bidirectional transcription displaying active-enhancer behaviour. PRO-seq captured a robust drought response at genes and revealed extensive remodelling of initiation landscapes. We detected 85,764 consensus dREG sites, of which 17,193 changed significantly under drought and were predominantly intergenic. Because plant intergenic space is rich in transposable elements and silencing-associated transcription, we integrated transposable-element overlap and small-RNA loci with chromatin accessibility and DNA methylation to prioritize 2,428 drought-responsive intergenic sites (841 induced and 1,308 repressed) that are accessible, locally hypomethylated, and bidirectionally transcribed - features consistent with enhancer-like elements. Activity at proximal candidates correlated with elevated nascent transcription of nearby genes, and a subset overlapped gene-connected chromatin loop anchors, supporting candidate enhancer-target relationships. Motif enrichment further supported the involvement of drought-responsive regulatory programs, and hundreds of candidates overlapped rice STARR-seq enhancers. Together, these data define a drought-responsive atlas of candidate enhancer-like nascent transcription in rice and provide prioritized cis-regulatory candidates for mechanistic validation and crop improvement.
Jankova-Drdova, E.; Haluska, S.; Kalachova, T.; Voloshina, M.; Pejchar, P.; Ortmannova, J.; Skrabalkova, E.; Drs, M.; Garcia-Gonzalez, J.; Kulich, I.; Batystova, K.; Pecenkova, T.; Antonova, A.; Zhivaeva, A.; Santrucek, J.; Janko, K.; Pleskot, R.; Cvrckova, F.; Zarsky, V.; Potocky, M.
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Plasmodesmata are intercellular channels that mediate symplastic communication between plant cells. Molecular transport through these channels is critically regulated by dynamic callose deposition and degradation, yet the secretory mechanisms that deliver regulatory components to plasmodesmata remain poorly understood. Here, we identify and characterize a non-canonical plasmodesmata-associated module of the exocyst, an evolutionarily conserved protein complex involved in secretory vesicle tethering and exocytosis. Exocyst subunits EXO70G1, SEC15A, EXO84C, and SEC10A specifically accumulate at plasmodesmata, whereas the canonical exocyst subunits EXO70A1 and SEC8 do not. Genetic and interaction analyses show that EXO70G1 acts as a landmark for recruiting SEC15A and EXO84C to plasmodesmata, revealing a distinct mode of exocyst targeting at these membrane domains. EXO70G1-dependent exocyst targeting to plasmodesmata depends on phosphoinositides and sphingolipids, consistent with the specialized lipid environment of plasmodesmal membranes. Loss of EXO70G1 results in increased callose accumulation and reduced symplastic transport, and strongly enhances developmental defects of a callose-overproducing mutant. In addition, exo70G1 mutants display enhanced resistance to bacterial pathogen Pseudomonas syringae, linking reduced plasmodesmal permeability to anti-bacterial defense. Cross-species analysis further indicates that plasmodesmata association is a derived feature of the EXO70G clade, present in angiosperms but absent from non-angiosperm EXO70 homologs. Together, our findings show that exocyst diversification in plants has generated a specialized trafficking module - plasmodesmata-associated exocyst - that links vesicle delivery to callose homeostasis at plasmodesmata, thereby regulating intercellular communication, development, and immunity. TeaserA specialized secretion module of the exocyst complex regulates plant cell-to-cell connectivity by controlling callose turnover at plasmodesmata
Wunder, T.; Holzner, L. J.; Manavski, N.; Bastürk, M. N.; Janowski, R.; Kunz, C. F.; Fechter, J.; Mühlbauer, S.; Rösch, F.; Meurer, J.; Legen, J.; Niessing, D.; Hagn, F.; de Vries, J.; Bölter, B.; Kunz, H.-H.
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Members of the K+ efflux antiporter (KEA) family fulfill key roles in plastids and the endomembrane system. Plants and green algae possess at least one KEA mediating K+/H+ exchange across the plastid inner envelope (IE) membrane. Recently, IE KEAs were shown to be essential for plastid gene expression (PGE), chloroplast development, and photosynthesis. Plants lacking these antiporters exhibit reduced stromal protein synthesis and accumulation of unprocessed rRNA precursors. KEA proteins comprise a conserved monovalent cation/proton antiporter 2 (CPA2) domain and a regulatory K transport and NAD-binding (KTN) domain. IE KEAs are distinguished by an additional ~500-amino-acid N-terminal extension containing a coiled-coil (CC) domain embedded within a largely intrinsically disordered region (IDR). Intrigued by this unusual architecture, we performed phylogenetic analyses, revealing that this N-terminal fusion arose early and has been conserved throughout the green lineage. We then investigated the oligomeric state, native distribution, and function of the N-terminal domain. Using Arabidopsis thaliana, we found that IE KEAs localize to discrete clusters within the inner envelope membrane and assemble into complexes of approximately 600 kDa. Finally, complementary approaches using a functional KEA1 variant lacking the core N-terminal domains (KEA1{Delta}N) indicate that this extension plays a regulatory rather than an essential role. Our findings uncover an evolutionarily ancient regulatory module that shapes the molecular organization and function of IE KEAs, advancing our understanding of plastid ion and pH homeostasis and plastid ribosome integrity.
Gu, J.; Chen, W.; Li, D.; Tang, H.; Li, X.
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Chromosomal variation underlies species evolution, but reconstructing its large-scale dynamics remains challenging, obscuring its adaptive significance. Here, we introduce GouMang, a framework that mines conserved genic section compositions across diverse species to trace karyotype evolution. In grasses, applied to 818 highly varied chromosomes spanning eight subfamilies, GouMang resolved a shared karyotype evolution path of 9-to-18 ({rho} whole genome duplication, {rho}WGD)-to-12 chromosomes, followed by lineage specific rearrangements or WGDs. Genes retained from the early {rho}WGD are linked to cold/light adaptation, supporting a key biomass expansion event that impacted subsequent global ecological pattern and human agricultural civilization, in which K-Pg global cooling and subsequent forest degradation drove early understory grasses to sun plants. Parallel analysis in Brassicaceae reconstructed karyotype evolution as well as {beta}WGD which unlinked to cold/light adaptation, reflecting a divergent biogeographic history compared to grasses. Together, GouMang depicts a widespread plant evolutionary pattern where karyotype constantly diversified with WGDs recurrently fueling adaptation.
Geyderowicz, O.; Gapinska, M.; Kossowska, H.; Mazur, R.; Zembek, P.; Iwanicka-Nowicka, R.; Krzymowska, M.; Poznanski, J.; Wu, K.; Kowalewska, Łucja; Koblowska, M.
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Progressive climate change is driving increasingly devastating crop losses through droughts, heatwaves and other adverse weather. Combined with shrinking arable land and spreading plant diseases, this makes it crucial to enable crops to grow efficiently in unfavorable, dynamic environments. Because stressors demand prompt, highly coordinated responses, plant stress adaptations rely heavily on epigenetic regulation. Histone deacetylases (HDAs), particularly class I, were recently shown to repress these responses. As constitutive defense is energetically costly, tools enabling temporal modulation of such mechanisms are highly sought after in crop biotechnology. This study evaluated whether valeric acid (VA), a five-carbon carboxylic acid, can inhibit HDA and activate plant defense responses. Here we show that VA is a potent HDA inhibitor that confers resistance to multiple abiotic and biotic stresses in Arabidopsis, and further validate the abiotic component in maize and tomato. Despite its simple chemical structure, structural and transcriptomic evidence shows that VA acts by selectively inhibiting two major stress-repressing deacetylases, HDA19 and HDA6. By targeting these epigenetic switches, VA activates natural defense and acclimation responses. Time-course transcriptomic analyses further revealed that priming with VA induces transcriptional memory, which, together with VA-induced metabolic rewiring, enables rapid and efficient responses to future stressors. Most importantly, despite activating energetically demanding defenses, VA promotes vegetative growth and increases yield under normal conditions, thereby breaking the growth-defense trade-off. These findings establish VA as the first epigenetic biostimulant of its kind, capable of improving plant performance under both abiotic and biotic stress while simultaneously increasing crop yield. As the epigenetic mechanisms underlying its action are evolutionarily conserved, VA priming emerges as a promising universal strategy to mitigate the climate-driven global crisis of crop losses.
Ammari, M.; Dash, L.; Choudhary, A.; Mamania, H.; Gupta, J.; Gnanarajah, M.; Gittens, K.; Zander, M.
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Transcription factors (TFs) orchestrate environmental responses by activating target genes, yet how they reshape epigenome architecture to coordinate gene expression remains poorly understood. We previously identified SIENA (Stimulus-Induced ENhancer Acetylation) domains as large regions of jasmonic acid (JA)-induced H3K9 hyperacetylation surrounding MYC2 TF binding sites in Arabidopsis and tomato. However, the mechanisms underlying the formation of SIENA domains (SIENAs) and their functional significance remained unknown. Here, we show that SIENAs also form at major JA-responsive genes and gene clusters in soybean, extending this phenomenon to an evolutionarily distant crop species. Comprehensive chromatin profiling revealed that SIENAs accumulate multiple histone acetylation marks, including H3K9ac, H3K27ac, H3K56ac, H2BK20ac, and H2A.Zac, establishing them as regions of broad histone hyperacetylation. Pharmacological disruption of proteasomal turnover and histone acetylation dynamics compromised SIENA formation. Chromatin accessibility analyses further showed that inducible accessibility within SIENAs is tightly associated with MYC2 binding sites, supporting a model in which MYCs nucleate localized chromatin reprogramming events. Together, our findings establish SIENAs as MYC2-dependent chromatin-organizing domains and identify histone hyperacetylation as a central feature of MYC2-mediated gene activation.
Qizhe, Z.; Zhengyang, Z.; Kepeng, L.; Wang, J.; Kaixuan, D.; Xianglei, X.; Wei, X.; Xuehai, H.
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High-quality plant genome assemblies are rapidly increasing, but accurate structural annotation remains reliant on transcript and homology evidence, limiting applications in newly sequenced and non-model species. Here, we present PlantGeneAnn, a plant-optimized, strand-specific genome foundation model for ab initio gene structure annotation. Fine-tuned on only nine high-quality model plant annotations, PlantGeneAnn outperformed a multi-species model trained on 42 species, showing that annotation quality is more important than token volume. On a stringent 13-species benchmark covering rosids, asterids, and monocots, PlantGeneAnn surpassed four state-of-the-art baselines across five evaluation levels, from base-level classification to complete transcript recovery. It achieved higher intron precision and better captured complex gene structures. In zero-shot variant effect prediction, PlantGeneAnn identified cryptic splice donors and premature stop codons in maize and rice, with saturation mutagenesis confirming single-nucleotide, context-dependent sensitivity. It also retained generalizability for epigenomic track prediction, highlighting its value for pan-genomics, crop improvement, and non-model plant research.
Markovic, V.;Bayle, V.;Dubois, G.;Rozier, F.;Amorim-Silva, V.;Morello-Lopez, J.;Grenet, S.;Garcia-Hernandez, S.;Botella, M.;Jaillais, Y.
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Eukaryotic cells are composed of different organelles that communicate with one another through direct contacts, which are necessary for a host of cellular reactions and for responding to different developmental and environmental changes. Plasma membrane (PM) forms extensive contacts with the endoplasmic reticulum (ER) at specific sites named ER-PM contact sites. These contacts play crucial functions in lipid homeostasis, Ca2+ regulation and signaling in all eukaryotes. However, the mechanisms by which plant ER-PM contact site proteins tether to the PM, as well as the dynamics of these contact sites, remain poorly understood. Here, we investigate the importance of phosphoinositides in the establishment and dynamics of ER-PM contact site proteins in plants. We found that phosphatidylinositol-4-phosphate (PI4P), rather than phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), is required for the association of ER-PM contact site proteins with the PM. Furthermore, we identified a PI4P phosphatase, SUPPRESSOR-OF-ACTIN7 (SAC7), that associates with the ER-PM contact site protein SYNAPTOTAGMIN1 (SYT1) and regulates its dynamic association with the PM. In particular, we found that in growing root hairs, a highly polarized cell type, SAC7 removes SYT1-containing contact sites at the growing tip. Consistently, optogenetic induction of ER-PM tethering reduced root hair elongation within minutes of blue light induction. Altogether, we propose a link between SAC7-mediated regulation of PI4P, dynamic ER-PM contact site establishment and polarized cell growth in plants.
Zhao, H.; Gou, B.; Liao, J.; Zhao, Y.; Yang, T.; Huang, P.; Zhu, Y.; Tie, Y.; Wang, M.; Gao, L.; Li, K.; Zhi, H.; Cui, X.; Chen, X.; Xu, Y.; Duan, K.; Wang, Y.; Tao, X.
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Nucleotide-binding leucine-rich repeat (NLR) immune receptor genes are of significant value in disease resistance breeding and the control of viral diseases. Soybean mosaic virus (SMV) poses a serious threat to soybean production and the Rsv1 locus in soybean cultivar Suweon 97 confers broad-spectrum resistance against SMV strains G1 to G7; however, this locus harbors no fewer than 18 NLR genes, and thus the broad-spectrum antiviral mechanisms underlying the Rsv1 locus remain poorly understood to date. Here, we established a rapid and highly efficient screening system for cloning NLR genes from soybean Rsv1 locus and identified a broad-spectrum antiviral NLR gene 13g184900 from this highly complicated locus. The NLR encoded by 13g184900 can recognize viral P3 protein from all SMV strains (G1-G7) and another potyvirus Bean common mosaic virus (BCMV). The coiled-coil (CC) domain of this NLR directly interacts with viral P3 protein. Additionally, we showed that this NLR originated from wild soybean accession in East China and has been introduced into several soybean cultivars during domestication. Collectively, we developed a high-throughput screening system for identifying NLR genes in soybean and our study provides new mechanistic perspective on how the Rsv1 locus mediates the broad-spectrum resistance to all SMV G1-G7 strains.
Courbier, S.;Schepetilnikov, M.;Hoernstein, S.;Lembke, I.;Meyer, C.;Huesgen, P.;Hiltbrunner, A.
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Plants perceive neighboring vegetation through an enrichment of far-red light (shade) in the environment. These changes in light quality trigger molecular and physiological responses aimed at outgrowing competitors, collectively known as the shade avoidance syndrome. In this study, we identify the TARGET OF RAPAMYCIN (TOR) complex 1 (TORC1), a major growth-regulating hub in eukaryotes, as a driver of shade-mediated growth responses in plants. Combining physiology, genetics, biochemistry, and proteomics, we show that TOR activity is rapidly enhanced upon shade perception and is required for proper shade responses, as TOR inhibition severely impairs shade-mediated elongation. Furthermore, we found that the control of shade-mediated elongation by TOR involves auxin-dependent mechanisms, requires efficient translation activity, and is closely linked to epidermal cell elongation capacity. Altogether, our work identifies TOR as a key integrator of light quality signals to control adaptive growth responses. Finally, we further highlight the conservation of shade-mediated TOR activation in tomato, with potential implications for engineering crop cultivars better suited to high-density planting.