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Plant Cell Reports

Springer Science and Business Media LLC

Preprints posted in the last 90 days, ranked by how well they match Plant Cell Reports's content profile, based on 17 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

1
Generation of lachrymatory factor synthase-suppressed onion (Allium cepa L.) by Agrobacterium-mediated gene transfer for CRISPR/Cas9 genome editing

Tamaru, S.; Imai, S.; Watanabe, S.; Ikegai, T.; Kondo, S.; Igawa, T.; Kamoi, T.

2026-07-22 plant biology 10.64898/2026.07.21.739049 medRxiv
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Lachrymatory factor, an irritating volatile with tear-inducing property, is produced when onion bulbs are cut or chopped. We aimed to generate onion plants with reduced lachrymatory factor synthase (LFS) activity via clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (CRISPR/Cas9) genome editing. Calli induced from primary roots were transformed with Agrobacterium tumefaciens carrying expression cassettes for CRISPR/Cas9, guide RNA, green fluorescent protein (GFP), and hygromycin resistance; callus lines that showed a high-frequency stable GFP expression were selected as "elite callus lines" that were suitable for transformation. Cleaved amplified polymorphic sequence (CAPS), heteroduplex mobility assay (HMA), and Sanger sequencing confirmed mutations introduced into the LFS gene, and plants were regenerated from the confirmed LFS-edited callus lines. The LFS enzyme activity in the leaves and bulbs of the LFS-edited plants was lower than that in control plants, while the LFS-edited plants exhibited severe growth abnormalities and failed to set seed, possibly due to long-term culture to maintain the elite callus line. The present study first demonstrated that onion genome editing, which modified a specific trait of onion, the reduction of LFS activity, was achieved. The results obtained opened the feasible way toward the final goal: the production of tear-free, higher health-functional onions.

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A GreenGate-compatible vector set for efficient protein purification from E. coli

Lopez-Bueno, M.;Anzenberger, F.;Lepper, A.;Bleckmann, A.;Denninger, P.

2026-06-15 Plant Biology 10.64898/2026.06.12.731827 medRxiv
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Recombinant protein purification from E. coli frequently requires screening various affinity tags and variations to optimize yield and purity. However, classical cloning methods are limited in throughput and modularity, which is circumvented by GoldenGate cloning. While GreenGate cloning, a GoldenGate variant, is widely used in plant research, it lacks compatibility with E. coli expression vectors. Here, we introduce a comprehensive, GreenGate-compatible vector toolkit for efficient and versatile assembly of three modules, for N- and C-terminal tagging of a protein of interest into an IPTG-inducible E. coli expression vector. To allow versatility, this toolkit contains diverse affinity tags, with or without HRV3C protease cleavage sites. Moreover, we included plasmids for the homemade low-cost production of this protease. This GreenGate-compatible toolkit allows efficient combinations of different tags and eliminates the need for re-cloning modules between plant and bacterial systems, streamlining the workflow for recombinant protein production, especially in plant research.

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VIRP1 bromodomain shapes nuclear condensate formation and has a positive effect on PSTVd accumulation

Bardani, E.; Ostendorp, S.; Andronis, C.; Asch, F.; Ostendrop, A.; Katsarou, K.; Kehr, J.; Kalantidis, K.

2026-06-10 plant biology 10.64898/2026.06.10.730826 medRxiv
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O_LIViroids are small, non-coding RNAs that rely on host factors for replication, intracellular trafficking and systemic movement. VIRP1, a Bromodomain and Extra-terminal domain (BET) protein, has previously been implicated in Potato spindle tuber viroid (PSTVd) infection, yet its precise role and mode of action remain unresolved. C_LIO_LIIn this work, we highlight VIRP1 as the only Solanaceae BET protein containing a proline-rich domain, which overlaps with the PSTVd-binding site. VIRP1-deficient plants exhibit delayed flowering and increased ABA sensitivity, with differentially expressed genes enriched in stress-related pathways. C_LIO_LIVIRP1 forms condensates in planta and in vitro, consistent with phase-separation behaviour. Condensate morphology is altered by PSTVd RNA, deletion of the intrinsically disordered CTD and bromodomain mutations. C_LIO_LIVIRP1 is particularly important for the early establishment of PSTVd infection, while nuclear localization and bromodomain integrity are required for efficient viroid accumulation. By contrast, the disordered CTD region is dispensable for complementation of PSTVd accumulation. C_LIO_LIOur results support a model in which VIRP1 acts as a host nuclear factor that links stress-related functions, nuclear condensate formation and early viroid infection. C_LI

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Port of Protein-Protein Interactomes: An experiment-based protein-protein interactome database for rice

Liu, X.; Lu, J.; Jia, L.; Xia, D.; Huang, J.; Cheng, Y.; Li, M.; Chen, Y.; Liu, X.; Li, G.; Liu, W.; Li, J.; Ying, J.; Wang, Y.; Li, Z.; Tong, X.; Hou, Y.; Zhiguo, E.; Zhang, J.; Zhang, J.

2026-08-20 systems biology 10.64898/2026.08.16.744343 medRxiv
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Protein-protein interactions (PPIs) play a crucial role in enabling proteins to carry out their functions within various biological processes (Hui et al., 2003). Since the introduction of the yeast two-hybrid (Y2H) method for PPI detection in 1989 (Fields and Song, 1989), the identification of PPIs has become a significant focus in modern biological research. PPI goes beyond examining individual proteins, allowing researchers to establish a comprehensive network that regulates biological processes. Rice, as a key model organism in plant biological studies, has been at the forefront of PPI research. In 2008, prominent rice scientists in China called for concerted efforts to define a comprehensive protein-protein interaction network experimentally, which aimed to facilitate the prediction of the functional mechanisms operating throughout a plants lifecycle (Zhang et al., 2008). With efforts for 2 decades, the experimentally identified rice PPIs have reached over ten thousand. Several public databases have been established to systematically collate and store PPIs, including STRING (Szklarczyk et al., 2019), BioGRID (Oughtred et al., 2020), IntAct (del Toro et al., 2022), PRIN (Gu et al., 2011), RicePPINet (Liu et al., 2017) and RiceNet v2 (Lee et al., 2015). However, most PPI datasets in rice stem from computational predictions, while experiment-based rice PPI datasets are fragmented due to the lack of systematic profiling at the rice PPIome level, which largely hinders information sharing in the rice research community. To bridge this gap, we constructed the Port of Protein-Protein Interactomes (POPPIN; https://riceome.hzau.edu.cn/poppin/), an integrated database dedicated to sharing experimentally verified PPIs and functional clues in rice. Empowered by high-throughput PPIome profiling technologies and text mining assisted by a large language model (Huang et al., 2025; Liu et al., 2025), POPPIN currently has deposited over 150,451 pieces of rice PPI-related information. Additionally, POPPIN provides detailed protein information, including GO annotations, subcellular localizations, domains, trait ontology (TO) information, and hyperlinks to external biological databases. Through offering a user-friendly web interface for search and dynamic network visualization, POPPIN serves as the first large-scale, experiment-based database for searchable PPIs in rice, and has the potential to be extended to other species under this structural framework.

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CRISPR-Cas9 Induced Knockout of BEL5 in Tetraploid Potato: Optimized Methodology via Repeated de novo Regeneration and Impact on Tuberization

Zounkova, A.; Chirivi, D.; Pribylova, A.; Martignago, D.; Myslivcova, J.; Masek, T.; Fischer, L.; Betti, C.; Fornara, F.; Maskova, P.

2026-07-22 plant biology 10.64898/2026.07.21.739726 medRxiv
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CRISPR-Cas9 has emerged as a powerful tool for targeted genome editing in plants; however, its application in tetraploid potato (Solanum tuberosum ssp. tuberosum) remains challenging due to its vegetative propagation and complex highly heterozygous genome. Availability of whole-genome sequence data for the specific genotype is crucial to ensure complete knockout of all alleles of target genes while minimizing off-target mutations. In this study, using the tetraploid potato cultivar Desiree, we report, a complete CRISPR-Cas9-mediated knockout of the BEL5 gene, encoding a transcription factor, known as one of the key regulators driving tuber formation. We employed Agrobacterium-mediated transformation and demonstrated that repeated de novo regeneration could improve editing efficiency by promoting emergence of new mutations. BEL5 knockout plants exhibited a delayed onset of tuberization under inductive short-day conditions in hydroponics; however, their overall tuber yields were comparable to wild type plants. Based on our results, we propose a regulatory role of BEL5 in the timing of tuber onset but, unexpectedly, its dispensability for tuber development in modern cultivated potato. Besides providing functional insight into the BEL5 role in potato, this study includes a methodological approach for efficient CRISPR-Cas9 gene editing in this vegetatively propagated polyploid crop, along with strategies for detecting mutations in genes that lack clear phenotypic manifestation.

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TurboID-based proximity-dependent labeling using SOBIR1 as a bait in potato leads to the identification of novel defense-related signaling partners

Marti Ferrando, T.; Landeo Villanueva, S.; Boeren, S.; Joosten, M. H. A. J.; Vleeshouwers, V.

2026-07-20 plant biology 10.64898/2026.07.19.739134 medRxiv
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The plant immune system comprises a complex signaling network that is activated upon perceiving molecules derived from invading pathogens. The first line of defense at the plant cell surface is mediated by receptor-like proteins (RLPs) and receptor-like kinases (RLKs). RLPs, which lack a cytoplasmic signalling domain themselves, constitutively interact with the RLK SUPRESSOR OF BIR1-1 (SOBIR1), which is a key component initiating immune signal transduction upon pathogen perception. Therefore, elucidating the composition of the SOBIR1 protein complex will contribute to understanding the basic molecular mechanisms of plant disease resistance. Most of the studies focused on the identification of SOBIR1-interacting proteins are limited to model plants, due to technical challenges and lack of reliable genome and proteome databases in crop plants. Here, we evaluate the application of the biotin ligase TurboID (TbID)-based proximity-dependent labeling (PL) approach by transiently expressing SOBIR1 from Nicotiana benthamiana (NbSOBIR1), fused to TbID in leaves of the wild potato Solanum microdontum. We show that NbSOBIR1-YFP-TbID properly accumulates in potato and that proximal proteins are biotinylated. Quantitative proteomic analysis yielded over 130 candidate proteins to be in the proximity of the cytoplasmic kinase domain of NbSOBIR1, of which some could be linked to disease resistance by KEGG pathway and gene ontology (GO) molecular function analysis. We also studied the dynamics of the proteome in proximity of NbSOBIR1 upon perception of the INF1 elicitin of Phytophthora infestans that was co-expressed in potato with the elicitin receptor ELR, which is an RLP that constitutively interacts with SOBIR1. We found more than 80 proteins, including the NB-LRR REQUIRED FOR HR-ASSOCIATED CELL DEATH 1 (NRC1), putatively interacting with NbSOBIR1. In conclusion, we were able to successfully apply PL in potato and a future roadmap for further research on deciphering the composition of protein complexes involved in immune signaling has been established.

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Benzyl Cyanide Triggers A Regeneration Program in Arabidopsis

Wojcikowska, B.; Marzec, M.; Falinska, J.

2026-07-21 plant biology 10.64898/2026.07.20.738417 medRxiv
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Phenylacetic acid (PAA) is a naturally occurring auxin whose biosynthesis and function during plant regeneration remain poorly understood. PAA may be synthesized from phenylalanine via the CYP79A2-dependent phenylacetaldoxime pathway, in which benzyl cyanide/phenylacetonitrile (BnCN/PAN) is a potential intermediate and substrate for NITRILASE (NIT) enzymes. Here, we investigated whether BnCN/PAN promotes somatic embryogenesis (SE) through NIT-dependent PAA biosynthesis. Low concentrations of BnCN/PAN stimulated somatic embryo formation in Arabidopsis thaliana, whereas exogenous PAA also promoted embryogenic induction. Transcriptome profiling revealed that BnCN/PAN upregulated genes associated with SE, including key embryogenic regulators and EMBRYO DEFECTIVE genes. RNA-seq data further indicated enhanced auxin signalling, which was independently confirmed using the pDR5::GUS reporter line. Inhibition of NIT activity by heatin reduced the embryogenic competence of BnCN/PAN-treated explants, supporting the involvement of NIT enzymes in this response. Collectively, our findings provide the first evidence that BnCN/PAN promotes embryogenic transition and suggest that NIT functions in SE extend beyond their proposed role in indole-3-acetic acid biosynthesis. Summary statementThis study uncovers a previously unrecognized pathway regulating plant regeneration, providing new insights into how naturally occurring metabolites influence embryo formation.

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The BUD13 splicing regulator: transcript structure and expression in ovules of sexual and apomictic Paspalum notatum

Draga, S.; Siena, L. A.; Colono, C.; Gabelli, G.; Podio, M.; Vega, M. S.; Palumbo, F.; Ortiz, J. P. A.; Barcaccia, G.; Pessino, S. C.

2026-07-08 plant biology 10.64898/2026.06.17.732924 medRxiv
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Background and AimsPaspalum notatum reproduces through either sexuality or apomixis, two pathways that may coexist within the same individual and are regulated by interconnected molecular networks responsive to environmental cues. Here, we characterized the transcript structure and expression of BUD SITE SELECTION PROTEIN 13 (BUD13), a component of the RES spliceosomal complex previously reported as differentially expressed in florets of sexual and apomictic plants, as a first step toward testing its involvement in the molecular regulation of the apomixis-sexuality switch. MethodsPreviously generated floral and leaf transcriptomes from sexual and apomictic Paspalum notatum plants, including Oxford Nanopore long-read data, were mined to characterize BUD13 transcript structure and expression. Phylogenetic analyses and in silico mapping were conducted to infer evolutionary relationships and determine the origin of the transcripts. Differential expression was validated by RT-qPCR, while in situ hybridization was used to reveal cell-specific ovule expression patterns. Key resultsBUD13 is expressed in Paspalum notatum florets as a truncated isoform (SHORT) encoding a small protein lacking part of the herpes simplex virus regulatory protein (ICP4) domain. Two SHORT transcripts, SHORT1 and SHORT2, with different 5' untranslated region (UTR) regions, were identified in flowers. SHORT1 was consistently upregulated in apomictic ovules from premeiosis to anthesis. Both transcripts originated from a single genomic locus located in the subtelomeric region of the short arm of chromosome 6. SHORT isoforms with variable structures were detected in other monocots. In situ hybridization showed that, whereas BUD13 was expressed throughout sexual ovules, expression was absent from the female germline of apomictic ovules. A consistent expression was observed in somatic proembryos of aposporous embryo sacs. ConclusionsOur findings reveal structural, spatial and temporal divergence in BUD13 expression between sexual and apomictic reproductive programs, providing new insights into the molecular regulation of asexual seed formation.

9
The combinatorial effect of terminators and introns on the levels and stability of stable transgene expression in plants

Ranawaka, B.; Shand, K.; Waterhouse, P. M.; de Felippes, F. F.

2026-08-19 plant biology 10.64898/2026.08.17.745381 medRxiv
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Most transgene applications require high and sustained expression, particularly in stably transformed plants. Achieving optimal transgene performance, however, depends on the combined influence of multiple genetic and regulatory factors. In previous work, we systematically evaluated the contribution of different genetic elements to transient transgene expression and demonstrated that terminators are key determinants of transgene performance by reducing transcriptional read-through and preventing transgene silencing. Here, we extend these findings by investigating the roles of terminators and introns in the expression of transgenes in stably transformed plants. Our results show that optimal transgene performance arises from the complementary actions of these two elements. Terminator choice was a major determinant of transgene expression levels, whereas introns played a critical role in maintaining expression stability. We further demonstrate a strong relationship between transgene expression levels and small RNA accumulation and show that intron-containing endogenous genes are enriched among highly expressed and stress-responsive genes, suggesting that intron-mediated protection from silencing may facilitate higher levels of gene expression and have contributed to the emergence and evolutionary retention of intron-containing genes.

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Immunoengineered Chitosanase-Produced Chitosan Oligomers for Elevating Plant Resistance to Viral Infection

Khanahmadi, S.; Singh, R.; Ryll, J.; Nava Cruz, N. Y.; Cord-Landwehr, S.; Richter, C.; Rafieerad, A.; Moerschbacher, B. M.

2026-06-10 plant biology 10.64898/2026.06.09.731087 medRxiv
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Chitooligomers can act as plant biostimulants or biopesticides, but todays chitosan-based agro-biologics often lack sufficient efficacy. This is due to a lack of scalable production processes for structurally well-controlled chitosans combined with a limited understanding of structure-function relationships. Chitosans differ in their degree of polymerization (DP), fraction and pattern of acetylation (FA and PA). While the influence of DP and FA on antimicrobial and phytostimulatory properties is at least partially known, this is not yet the case for PA. PA can be partially controlled by using enzymatic rather than acid hydrolysis for oligomer production. We have used recombinant chitinases and chitosanases to hydrolyse a well-characterised chitosan polymer, and purified oligomers with different DP. We have structurally characterised the products and tested their abilities to protect tobacco from viral disease. Chitinase products were dominated by GlcNAc units at their reducing and non-reducing ends, with GlcN units dominating their centers, and v.v. for chitosanase products. While the chitinase-derived hydrolysates were inactive, the chitosanase-derived oligomers possessed elicitor and priming activities and protected plants from disease, and their activity increased with increasing DP. Clearly, the Bacillus chitosanase used is well-suited to set up a scalable production process for chitosan oligomers with promising agro-biologic properties. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=95 SRC="FIGDIR/small/731087v1_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@c312e9org.highwire.dtl.DTLVardef@10eaf99org.highwire.dtl.DTLVardef@12a937corg.highwire.dtl.DTLVardef@38dc8c_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Phytoplasma mediated transcriptional changes in poinsettia buds suggest MAF3 and bZIP67 transcription factors as potential suppressors of shoot branching

Darbani, B.;Ingvardsen, C.;Holme, I.;Moller, M.;Graff, J.;Brinch-Pedersen, H.;Nicolaisen, M.

2026-06-17 Plant Biology 10.64898/2026.06.16.732632 medRxiv
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O_LIShoot branching is critical not only in breeding for yield but also for ornamentals architecture. In the ornamental plant poinsettia (Euphorbia pulcherrima), shoot branching has traditionally been induced by phytoplasma (Candidatus Phytoplasma pruni) inoculation. This study aimed to identify regulatory genes that could be leveraged in future breeding-by-genetic engineering efforts to develop phytoplasma-free, branching poinsettia plants. C_LIO_LITo elucidate mechanisms of phytoplasma-induced shoot branching, we performed RNA-sequencing and assembled an axillary bud-specific transcriptome for expression analyses in phytoplasma-infected and -free poinsettia. Phenotyping and RNA-sequencing were also conducted on Arabidopsis mutants and wild-type lines to investigate the transcriptional regulatory effects of candidate genes. C_LIO_LIThe transcription factors EpMAF3 and EpbZIP67 were highly de-regulated in phytoplasma-infected poinsettia. We also found a two-fold increase in primary-stem branching levels of the Arabidopsis maf3 and bzip67 mutants, suggesting the two transcription factors as potential shoot branching suppressors. AtTcp1, a CYC-clade TCP transcription factor, was up-regulated (78x) in leaves of the maf3 mutants. Analyzing previously reported protein-level interactions for the differentially expressed genes (e.g., AtClamt, AtGh3.9/3.15, AtSaur32/36, AtAbi3, AtGamt2, AtTcp3, and AtDwf4) in bzip67 mutants shed light on other shoot branching regulators such as TCPs, PINs, ABIs, DWARF14, and BES1, highlighting two regulatory sub-networks including membrane transport and hormonal signaling. C_LIO_LIThe results open the way to rational engineering of shoot branching in poinsettia by targeted mutagenesis of MAF3 and bZIP67. In that way, the tedious and viral-infection prone process of phytoplasma inoculation can be avoided and poinsettia plants would have more homogenous branching. C_LI One-sentence summaryPhytoplasma infection in poinsettia induces bud-specific repression of the transcription factors EpMaf3 and EpbZip67, consistent with the enhanced stem branching observed in Arabidopsis maf3 and bzip67 mutant lines.

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Exploring the potential role of the TETRATRICOPEPTIDE THIOREDOXIN-LIKE gene family in nitrogen-fixing and water-restricted soybean plants

Sainz, M.;Filippi, C.;Pezzutto, S.;Eastman, G.;Sotelo-Silveira, J.;Borsani, O.;Sotelo-Silveira, M.

2026-06-23 Plant Biology 10.64898/2026.06.22.733792 medRxiv
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The TETRATRICOPEPTIDE THIOREDOXIN-LIKE (TTL) proteins are a plant-specific family proposed to function as peripheral membrane proteins that contribute to abiotic stress tolerance in Arabidopsis, likely by maintaining cell wall integrity through brassinosteroid signaling. Previously, we identified a TTL gene that was differentially regulated at the translational level in nitrogen-fixing soybean plants under water deficit (WD) conditions. This finding prompted the characterization of the soybean TTL gene family. Using the Glycine max v4.0 proteome, we identified ten TTL homologs (GmTTL1-GmTTL10), which are unevenly distributed across five chromosomes. Phylogenetic and structural analyses grouped these genes into three clades and revealed a highly conserved exon-intron organization. Likewise, GmTTL proteins display a conserved number and arrangement of TPR and TRXL motifs. To gain insights into their potential biological functions, we integrated co-expression and differential expression analyses. This approach identified a co-expression module enriched for translationally downregulated genes related to the Gene Ontology terms "cellular anatomical entity", "membrane", "cell periphery", "cell wall modification", "nitrate assimilation", and "cell wall organization or biogenesis". Protein-protein interaction network analysis of this specific subset of genes uncovered a novel GmTTL connection with two nitrate reductase enzymes in nitrogen-fixing plants subjected to WD, potentially linking the TTL gene family to new functions or roles. This study provides a framework for future functional studies of GmTTL proteins and their contribution to abiotic stress adaptation in soybean. Key MessageThis work presents the first functional characterization of TTLs proteins in legume species and highlights key processes that may link the TTL gene family to new functions or roles.

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Dynamic Patterns of Nuclear Transcription Factor Abundance in Plant Basal Immunity Revealed by Spatial Proteomics of Arabidopsis Nuclei

Ayash, M.; Proksch, C.; Thieme, D.; Bauer, N.; Lee, J.; Heilmann, I.; Hoehenwarter, W.

2026-07-09 plant biology 10.64898/2026.06.30.735533 medRxiv
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O_LIThe control of amount of nuclear proteins is fundamental in regulating plant gene expression, but the mechanisms of quantitative dynamics of the nuclear proteome are largely unstudied during adaptive responses to pathogens. C_LIO_LIHighly specific labeling, enrichment and measurement of the nuclear proteome was performed using TurboID LC-MS of Arabidopsis thaliana leaves treated with the pathogen-associated molecular pattern (PAMP), flg22, and/or cycloheximide. The chosen experimental approach allowed discrimination of the effects of translation, nuclear protein import, trafficking of preexisting proteins, derepression, and nuclear protein turn-over upon elicitation of basal immunity. C_LIO_LIThe highly specific, deep coverage of proteins in the nucleus makes this study a resource for anyone interested in plant nuclear proteome dynamics and defense. C_LIO_LIAround 2,000 nuclear proteins were repeatedly quantified, including more than 300 transcription factors or other proteins related to transcription. Several proteins with documented activity in endosomes were newly synthesized and imported into nuclei upon PAMP challenge, suggesting alternative nuclear functions in PAMP-triggered immunity (PTI). Circadian clock components, including the transcription factor, CIRCADIAN CLOCK ASSOCIATED 1 (CCA1)-HIKING EXPEDITION (CHE), were depleted upon PAMP challenge, suggesting a safeguard against untimely induction of systemic acquired resistance (SAR). C_LIO_LIBased on proteomic patterns, proteins moonlighting in the nucleus as well as trafficking and turn-over regulation of the proteome are common elements during plant immunity. C_LI

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miR319 promotes de novo shoot regeneration by repressing LsTCP4 in lettuce

Jiang, T.; Tanwir, S. E.; Karn, A.; Liu, F.; Huo, H.

2026-07-09 plant biology 10.64898/2026.07.08.737254 medRxiv
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Plant regeneration is a major determinant of transformation and genome-editing efficiency, yet the endogenous regulatory networks controlling regenerative competence in horticultural crops remain incompletely understood. The miR319-TCP module regulates multiple developmental processes in plants, but its function in lettuce regeneration has not been defined. Here, we performed a genome-wide analysis of the TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) gene family in lettuce (Lactuca sativa). Thirty-three LsTCP genes were identified and classified into Class I/PCF, Class II/CIN, and Class II/CYC/TB1 groups. Five CIN-class genes, LsTCP2, LsTCP3, LsTCP4, LsTCP10, and LsTCP24, were predicted as high-confidence miR319 targets and supported by degradome-based cleavage evidence. MIR319-overexpression (OX319) explants showed enhanced de novo shoot regeneration, with 94.5% regeneration efficiency and 1.92 shoots per explant, whereas STTM-miR319 suppression (S319) explants showed reduced regeneration, with 28.5% regeneration efficiency and 0.36 shoots per explant. These phenotypes were associated with altered expression of several miR319-targeted CIN-TCP genes, particularly LsTCP4, LsTCP10, and LsTCP24. Disruption of LsTCP4 increased regeneration efficiency to 91.4% and shoot production to 2.05 shoots per explant, resembling the regeneration-enhancing effect of miR319 overexpression. In contrast, disruption of the non-target CIN gene LsTCP17 did not significantly affect regeneration under the tested conditions. Together, these results identify LsTCP4 as a key miR319-responsive negative regulator of de novo shoot regeneration and highlight miR319-mediated repression of LsTCP4 as a potential endogenous strategy for improving lettuce regeneration.

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Natural variation in NifU and NifS enhances chloroplasts compatibility for nitrogenase engineering

Ene-Ordorica, M.; Vaca-Sanz, C.; Makarovsky-Saavedra, N.; Sanchez, A. O.; Blasio, F.; Curatti, L.; CARO, E.; Rubio, L. M.

2026-07-14 plant biology 10.64898/2026.07.09.737459 medRxiv
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Reconstitution of functional nitrogenase in plants requires the coordinated expression of the [Fe-S] cluster assembly proteins NifU and NifS. However, the extent to which these proteins interact with endogenous Fe-S metabolism and affect plant physiology remains unclear. Here, we compared NifU and NifS homologs from diverse diazotrophs to identify variants compatible with the plant chloroplast environment. Selected variants of Azotobacter vinelandii, Fischerella thermalis, and Marinobacter lutimaris were characterized by transient expression in Nicotiana benthamiana and stable transformation in rice. Plant-produced NifU was largely devoid of [Fe-S] clusters when isolated but retained strong capacity for in vitro [Fe-S] cluster reconstitution and apo-NifH activation in a Ft > Av >Ml gradient, indicating correct folding and function but limited cluster loading or stability in vivo. NifU and NifS expression in transgenic rice resulted in variant-dependent proteome and phenotype effects, with A. vinelandii-expressing lines exhibiting severe defects, F. thermalis lines showing intermediate phenotype, and M. lutimaris lines being indistinguishable from wild type. These results reveal a trade-off between the biochemical activity of NifU and NifS and their compatibility with host metabolism, which must be considered for successful nitrogenase engineering in plants. HighlightNifU/NifS homolog selection determines trade-offs between [Fe-S] cluster assembly activity and plant compatibility, identifying variants that minimize physiological disruption while supporting nitrogenase cofactor assembly in chloroplasts.

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Immobilized dicot and monocot viral vectors enable rapid screening of RNA mobility elements for mobile RNA engineering and RNA-based genome editing

Butler, N. M.; Grahn, C. M.; Starker, C.

2026-08-03 plant biology 10.64898/2026.07.31.741600 medRxiv
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RNA mobility has emerged as a valuable component of RNA-based genome editing and DNA-free transformation technologies. However, experimental systems for rapidly evaluating RNA mobility remain limited, particularly in monocot species where grafting approaches are not feasible. Here, we developed immobilized versions of Foxtail Mosaic Virus (FoMV) and Tobacco Rattle Virus (TRV) with impaired systemic viral movement as generalizable platforms for transient expression and functional screening of mobile RNAs. A simple Nicotiana benthamiana leaf assay enabled direct visualization and molecular quantification of transcript mobility using fluorescent reporter fusions carrying seven previously described RNA mobility elements from dicot and monocot species. The platform consistently distinguished mobile elements displaying higher or lower frequencies of mobility across both viral systems, with T-RNA-like sequence (TLS), TLSgly and maize FLOWERING LOCUS T (FT) ortholog, ZCN19, and as well as ZCN16 displaying significantly higher frequencies of mobility compared to non-mobile element controls in FoMV and TRV, respectively. Translation of these findings to virus-induced genome editing demonstrated that mobile elements identified through the screening platform enhanced FoMV-mediated editing of PHYTOENE DESATURASE in Setaria viridis (SvPDS), with TLSgly increasing somatic editing frequencies approximately two-fold relative to sgRNA alone. Together, these results establish immobilized FoMV and TRV platforms as versatile screening tools for evaluating RNA mobility, optimizing RNA cargos for viral genome editing, and a scalable framework for engineering mobile RNAs and accelerating development of RNA-based technologies for functional genomics and crop improvement.

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FERONIA and ANJEA do not have a conserved role in self-incompatible Arabidopsis for self-pollen rejection.

Chadic, P.; Sidsworth, A.; Goring, D.

2026-08-10 plant biology 10.64898/2026.08.07.743519 medRxiv
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The rejection of self-incompatible (SI) Brassica pollen is mediated by three signaling branches that function in parallel in the stigma. The recognition of SI pollen by the stigma S-Receptor Kinase (SRK) results in activation of the ARM-Repeat-Containing 1 E3 ubiquitin ligase (ARC1) which mediates the degradation of compatibility factors, the FERONIA (FER) and ANJEA (ANJ) receptor kinases that induces ROS accumulation to inhibitory levels and the M Locus Protein Kinase (MLPK) which may also be connected to ROS production. Arabidopsis self-incompatibility is regulated by SRK as well, but the signaling events downstream of SRK following SI pollen perception are less well-understood. In this study, we evaluated the requirements of FER, ANJ and HERCULES RECEPTOR KINASE 1 (HERK1) for SI pollen rejection in the transgenic Arabidopsis thaliana SI-Col-0{psi} srka-1 line. The{psi} srka-1 T-DNA disrupting the expression of the endogenous{psi} SRKA gene was crossed into SI-Col-0 to prevent any potential SRK transgene silencing. T-DNA mutants for FER and ANJ/HERK1 were then crossed into the SI-Col-0{psi} srka-1 line. Using standard assays for pollen-stigma interactions, the SI phenotypes were assessed for the SI-Col-0 fer, SI-Col-0 anj-1 and SI-Col-0 anj-1 herk1-1 lines. Our results presented here indicated that FER and ANJ are not required in the stigma for Arabidopsis SI pollen rejection, further providing evidence for a divergence in the SI downstream signaling pathway in Arabidopsis.

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Arabidopsis exocyst complex subunit EXO70E2 in defence against Pseudomonas syringae in conjunction with autophagy

Yıldız, A. B.; Potocka, A.; Caldarescu, G. A.; Batik, A.; Sabol, P.; Zarsky, V.

2026-07-09 plant biology 10.64898/2026.06.30.735562 medRxiv
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Exocyst was initially uncovered in yeast genetic sec-screen as a tethering complex for exocytotic vesicles and this function was later found to be evolutionarily conserved in other eukaryotes including plants. Later however, a surprising engagement of the exocyst complex in autophagy was observed in animals, plants and recently also in yeast. Using the genetic approach we observed EXO70E2 exocyst complex subunit engagement in the defence response to Pseudomonas syringae attack linked to the autophagy pathway. CRISPR/CAS LOF mutant of EXO70E2 is more sensitive to Pseudomonas infection (both virulent as well as T3SS mutant) and autophagy flux monitored by NBR1 antibody is compromised in comparison to WT. We conclude that the plant exocyst complex linked to the EXO70E2 subunit participates in defence against Pseudomonas bacteria in conjunction with the autophagy pathway. HighlightArabidopsis exocyst subunit EXO70E2 affects selective autophagic flux monitored by NBR1 and is participating in defense against Pseudomonas syringae infection.

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VC1 and the production of vicine and convicine in the genus Vicia

Vottonen, L. L.; Chang, W.; Pöysä, M.; Lampi, A.-M.; Tanskanen, J.; Schulman, A. H.; Stoddard, F. L.

2026-07-14 plant biology 10.64898/2026.07.09.737524 medRxiv
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Many Vicia species contain vicine and convicine (VC), which limit the use of faba bean and some vetches in food and feed. The first step in VC biosynthesis in V. faba is shared with the riboflavin pathway and attributed to VC1, a member of the ribAB family. Since riboflavin is ubiquitous to life, we examined the distribution of VC production in genus Vicia. Three accessions of each of 33 Vicia species were grown in glasshouse conditions to provide fresh seeds for VC analysis and leaves for DNA analysis. PCR was used to amplify fragments of the VC1/ribAB gene for sequencing, and these sequences were used to create a phylogenetic tree. COX1 and ITS2 sequences were used for examining the nucleotide diversity in the subgenera. VC and DNA sequences consistent with VC1 were found only in members of subgenus Vicia. In V. lathyroides, VC1 was present but no VC was detected. There was less sequence diversity in VC1/ribAB sequences of subgenus Cracca than in those of subgenus Vicia, suggesting that ribAB remained under stricter purifying selection than VC1. VC1 is confirmed as a prerequisite for the presence of VC, and the gene and its products are restricted to subgenus Vicia. HighlightThe favism-causing factors of vetches and faba bean, vicine and convicine, depend on the presence of the VC1 variant of the ribAB gene, which is found in only one subgenus.

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AgroGem: A Rapid and Scalable Transient Transformation System for Functional Genetics in Multiple Plant Species

Guo, S.; Schlegel, O.; Kumar, J.; Myers, Z.; Kianian, S.; Greenham, K.; Zhang, F.

2026-07-10 plant biology 10.64898/2026.07.03.736435 medRxiv
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Plant genetic transformation technologies are essential for functional genomics and genome engineering in plants. While transient expression systems offer a rapid alternative to stable transformation, existing platforms are often constrained by low efficiency, technical complexity, and limited scalability. Here, we developed AgroGem, an efficient Agrobacterium-mediated transient transformation system utilizing a geminiviral replicon-based T-DNA vector for Arabidopsis and Brassicaceae species. AgroGem significantly outperformed existing transient approaches, including AGROBEST and protoplast-based assays, in CRISPR-mediated editing efficiency. Moreover, AgroGem recapitulated the mutation spectra and chromatin accessibility-dependent editing patterns observed in stable transformation across both Cas9 and Cas12a systems, indicating that it captures genome editing outcomes in native chromatin contexts. Leveraging this capability, we performed high-resolution profiling of CRISPR-induced mutation outcomes across a panel of DNA repair mutants and identified distinct repair signatures, including unexpected roles for KU80 and XRCC4 in regulating non-homologous end joining (NHEJ). AgroGem also supported bimolecular fluorescence complementation assays for protein-protein interaction studies in Arabidopsis and was readily adapted to plate-based formats for high-throughput applications. Together, these results establish AgroGem as a robust, scalable, and versatile platform for genome editing, DNA repair analysis, and functional genetics in plants.