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Results for “Transient expression”

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At least 19 recordsLinked to original sources

PubMed1975

Regulation of mitochondrial membrane assembly in Neurospora crassa. Transient expression of a respiratory mutant phenotype.

Cultures of mutant cni-1, a chromosomal mutant of Neurospora crassa, undergo a marked change in respiratory properties as the age of the culture increases. Early log phase cultures have a high level of respiration that is insensitive to inhibition by cyanide or antimycin A. Late log and stationary phase cultures have reduced rates of respiration. A high percentage of this respiration is inhibited by cyanide. Mitochondria from early log phase cni-1 have an excess of cytochrome c and little or no detectable cytochrome aa3. Mitochondria from late log and stationary phase cultures have levels of c-, b-, and a-type cytochromes that are not significantly different in concentration from those found in wild type cells. The cytochrome aa3 content and the cytochrome oxidase activity of cni-1 mitochondria increase 5- to 10-fold as the age of the culture increases. Mitochondria from early log phase cells of cni-1 synthesize only polypeptides of apparent molecular weights 7,000 to 10,000 and donot synthesize any of the mitochondrial components of cytochrome oxidase. Mitochondria from late log and stationary phase cells synthesize the normal complement of mitochondrial translation products including the mitochondrial components of cytochrome oxidase. The assembly of cytochrome oxidase is likely due to the availability of the mitochondrially synthesized components of the enzyme. The regulation of mitochondrial translation in the cni-1 mutant is independent of the nutrient content of the growth medium and is due to the accumulation or depletion of some component within the cell.

Cell Division↗

PubMed1977

Transient virus expression during murine leukemia induction by X-irradiation.

Most X-irradiation-induced thymomas in C57BL/6 mice are virus-free when assayed by immunofluorescence for the gs antigen (gsa) of murine leukemia virus (MuLV). Virus was induced transiently in bone marrow cells and later appeared in thymus cells. Six to 7 weeks post irradiation, thymocytes and bone marrow cells were MuLV gsa-negative and remained negative for the lifetime of most animals, whether or not they contracted overt leukemia. During the period when MuLV gsa-positive bone marrow cells were found, XC-positive syncytia-producing bone marrow cells were also found. Virus information was expressed, therefore, for a limited duration, long before any signs of leukemia in the animals were evident. MuLV gsa-positive thymocytes taken from mice 4 weeks after X-irradiation were cocultivated with a series of indicator cells. B-tropic virus, in addition to a xenotropic virus, was isolated from these cells. Ecotropic virus was not found in normal mouse thymocytes, in irradiated thymocytes a few days after termination of the X-irradiation sequence, or in most primary thymomas. All thymocytes produced only xenotropic virus in the cocultivation assays. Expression of the ecotropic virus was, therefore, transient, as assayed by immunofluorescence, XC syncytia formation, and virus isolation from MuLV gsa-positive thymus cells.

Animals↗

PubMed2026

Pri micropeptide functions as a cell-intrinsic timer controlling the transient phase of cell fate induction.

During development, cells sequentially acquire specific fates through temporally ordered regulatory systems. To ensure the harmonious progression, each system must be activated and subsequently inactivated at the appropriate time. In this study, we show that the duration of fate induction is controlled by the transient expression of polished rice (pri), a gene encoding micropeptides, during Drosophila tracheal development. pri is transiently expressed in prospective tracheal placodes and precedes the expression of trachealess (trh), a master transcription factor that initiates tracheal fate. pri induces the expression of trh through promoting the disappearance of the repressor form of the transcriptional factor Shavenbaby (Svb). Conversely, after placode invagination, artificially prolonging pri expression or constitutive loss of Svb leads to ectopic maintenance of trh expression in noninvaginated placode cells surrounding the properly invaginated domain. These results indicate that the rapid disappearance of pri properly terminates the initial fate induction system and suggest that this termination ensures a smooth transition to the subsequent fate-regulatory program-that is, the maintenance of tracheal cell fate specifically in the invaginated cells. Together, we propose that the transiency of pri serves as a cell-intrinsic molecular timer that controls the transient phase of cell fate induction and ensures the transition between sequential fate-regulatory systems, thereby enabling the precise coordination of cell identity with morphogenesis during organogenesis.

Animals↗

PubMed2025

Multi-Omics Analyses Reveal the Red and Far-Red Light Combination Enhancing Heterologous Protein and Metabolite Production in Nicotiana benthamiana.

Transient expression of exogenous protein in Nicotiana benthamiana leaves via agroinfiltration offers a rapid and efficient platform for functional gene discovery and heterologous production of valuable eukaryotic proteins and metabolites. Though light quality is an important factor for plant photomorphogenesis, its impact on the efficiency of transient expression remains unexplored. In this study, we examined the influence of five representative light qualities with varying wavelength mix on the N. benthamiana growth and recombinant green fluorescent protein (GFP) production. Plants with red and far-red light treatment (LED-red) showed the highest GFP expression, 57.4% higher than white light. Further study showed that a higher dosage of post-infiltration Agrobacterium and the resulting increase in the number of transcripts contribute to the expression rate enhancement. Moreover, as for exogenous metabolites, a 76.5% increase of accumulated taxadiene was also observed in LED-red group. Integrated transcriptomic, proteomic and metabolomic revealed that LED-red plants reduced the resistance pathways before infiltration, inducing a higher dosage of post-agroinfiltration Agrobacterium. Our results suggest that N. benthamiana grown under LED-red creates a more favorable environment for Agrobacterium growth, enhancing heterologous protein and metabolite production. This study highlights the potential utilization of light quality as an implementable tool in plant synthetic biology.

Nicotiana↗

PubMed2026

Genome-Wide Identification of the Soybean GH5 Gene Family and Functional Analysis of GmGH5-22 in Salt Tolerance.

Plant GH5 family genes function in both cell wall biosynthesis and stress responses. However, comprehensive studies on GH5 genes in the soybean remain limited. Here, we identified 28 GmGH5 genes from the soybean genome. Phylogenetic analysis assigned these genes to three subfamilies (I-III), with no representatives in subfamily IV. The GmGH5 family harbors 15 conserved motifs, which are largely similar within subfamilies but differ across subfamilies. Additionally, exon-intron structures (2-7 introns) exhibit clade-specific patterns, with members within the same clade sharing similar intron numbers and lengths, whereas distinct clades show some variation. The promoter regions of GmGH5 genes contained various cis-acting regulatory elements associated with stress responses and developmental processes. Transcriptome-based expression profiling revealed distinct tissue-specific expression patterns of GmGH5 genes. RT-qPCR further confirmed their differential expression under salt, alkaline, cold, and drought stresses, especially a significant increase in GmGH5-22 expression under salt stress (approximately 22-fold at 6 h, **** p < 0.0001). Furthermore, GmGH5-22 was highly expressed in roots, and transient expression in tobacco leaves showed its peripheral localization, which aligns with its predicted extracellular localization, suggesting that GmGH5-22 is highly likely localized to the cell wall. Overexpression of GmGH5-22 in soybean hairy roots significantly improved tolerance to salt stress. These findings establish a foundation for functional characterization of GmGH5 genes and provide viable targets for molecular breeding to enhance salt tolerance in soybeans.

GH5 family↗

PubMed2025

A transient mutational burst occurs during yeast colony development.

Characterizing the contribution of mutators to mutation accumulation is essential for understanding cellular adaptation and diseases like cancer. By measuring single and double mutation rates, including point mutations, segmental duplications, and reciprocal translocations, we found that wild-type yeast colonies exhibit double mutation rates up to 17 times higher than expected from experimentally determined single mutation rates. These double mutants retained wild-type mutation rates, indicating they originated from genetically normal cells that transiently expressed a mutator phenotype. Numerical simulations suggest that transient mutator subpopulations likely consist of less than a few thousand cells, and experience high-intensity mutational bursts for less than five generations. Most double mutations accumulated sequentially across cell cycles, with simultaneous acquisition being rare and likely linked to systemic genomic instability. Additionally, we explored the genetic control of transient hypermutation and found that the excess of double mutants can be modulated by replication stress and the DNA damage tolerance pathway. Our findings suggest that transient mutators play a significant role in genomic instability and contribute to the mutational load accumulating in growing isogenic populations.

Saccharomyces cerevisiae↗

PubMed1976

Transformation of Chinese hamster embryo cells with an avian sarcoma virus ts mutant.

Chinese hamster embryo cells were transformed with temperature-sensitive mutant of the Schmidt-Ruppin strain of Rous sarcoma virus-subgroup A (ts NY68S Ra-A). The developed cell line elicited the morphological transformation at a permissive temperature of 35 degrees C, whereas after a shift to a non-permissive temperature of 40 degrees C the cells reverted to a normal phenotype. Tests for the presence of avian sarcoma group-specific antigen showed that the antigen was not expressed both at permissive and non-permissive temperature. However, the transient expression of gs antigen could be achieved by treatment with 5-IUdR only at the permissive temperature. There was a difference in the rate of 14C-2-deoxy-D-glucose uptake between cells cultured at the permissive and non-permissive temperature.

Animals↗

PubMed2026

GA4+7 alleviates pear fruit semi-russeting partly by suppressing PRX-mediated lignin deposition.

Pear fruit semi-russeting is a surface disorder that frequently occurs during fruit development and significantly diminishes fruit appearance quality and commercial value. Although Gibberellin 4 + 7 (GA4+7) has been used to reduce fruit surface defects in horticultural crops, the physiological and molecular mechanisms underlying its inhibitory effect on pear fruit semi-russeting remain poorly understood. In this study, preharvest GA4+7 treatment of 'Cuiguan' pear significantly reduced russet coverage and lignin accumulation in mature fruit skin without adversely affecting fruit size, fruit shape index, or total soluble solids content. Integrated metabolomic and transcriptomic analyses revealed that GA4+7 treatment was associated with the repression of phenylpropanoid and lignin biosynthesis at both metabolic and transcriptional levels. Among the lignin-related differentially expressed genes, two class III peroxidase genes, PpyPRX22 and PpyPRX65, were strongly downregulated by both GA4+7 and bagging treatments. Both proteins localized to the cell wall, and transient expression assays in pear fruit skin supported positive roles for PpyPRX22 and PpyPRX65 in lignin deposition. Furthermore, dual-luciferase reporter assays combined with transient overexpression experiments suggested that several PpyMYB transcription factors may regulate PpyPRX expression and lignin accumulation, with PpyMYB138 and PpyMYB139 significantly activating PpyPRX22 and/or PpyPRX65 promoter activity. Taken together, these results suggest that GA4+7 alleviates pear fruit semi-russeting at least partly by reducing lignin deposition in the fruit skin, with PpyPRX22 and PpyPRX65 potentially contributing to this process.

Class III peroxidase↗

PubMed2026

PtoeIF5A1: A Pleiotropic Regulator of Development, PCD, and Salt Tolerance in Populus tomentosa.

Eukaryotic translation initiation factor 5A (eIF5A) is a highly conserved protein family unique to eukaryotes, yet its functional characterization in woody plants remains limited. In this study, we identified four eIF5A genes (PtoeIF5A1-PtoeIF5A4) from the genome of Populus tomentosa, a fast-growing tree species indigenous to China, and characterized their expression patterns and functional roles through bioinformatics analysis, quantitative real-time PCR, stable overexpression in Arabidopsis thaliana, and transient expression in Nicotiana benthamiana leaves. Our results demonstrated that all PtoeIF5A proteins contain a conserved OB-fold domain and multiple phosphorylation sites, with PtoeIF5A1 showing predominant expression in roots and secondary xylem. Functional assays revealed that PtoeIF5A1 overexpression accelerated inflorescence stem elongation and early flowering in Arabidopsis, induced visible chlorosis and programmed cell death (PCD) in tobacco leaves, and significantly enhanced salt tolerance under NaCl treatment. Collectively, these findings establish PtoeIF5A1 in poplar as a pleiotropic regulator integrating developmental cues, programmed cell death, and stress responses; and as a valuable genetic resource for breeding stress-resilient woody plants.

Populus tomentosa↗

PubMed2005

Oct-1 counteracts autoinhibition of Runx2 DNA binding to form a novel Runx2/Oct-1 complex on the promoter of the mammary gland-specific gene beta-casein.

The transcription factor Runx2 is essential for the expression of a number of bone-specific genes and is primarily considered a master regulator of bone development. Runx2 is also expressed in mammary epithelial cells, but its role in the mammary gland has not been established. Here we show that Runx2 forms a novel complex with the ubiquitous transcription factor Oct-1 to regulate the expression of the mammary gland-specific gene beta-casein. The Runx2/Oct-1 complex forms on a Runx/octamer element which is highly conserved in casein promoters. Chromatin immunoprecipitation, RNA interference, promoter mutagenesis, and transient expression analyses were used to demonstrate that the Runx2/Oct-1 complex contributes to the transcriptional regulation of the beta-casein gene. Analysis of the complex revealed autoinhibitory domains for DNA binding in both the N-terminal and the C-terminal regions of Runx2. Oct-1 stimulates the recruitment of Runx2 to the beta-casein promoter by interacting with the C-terminal region of Runx2, suggesting that Oct-1 stimulates Runx2 recruitment by relieving the autoinhibition of Runx2 DNA binding. These findings demonstrate that Runx2 collaborates with Oct-1 and contributes to the expression of a mammary gland-specific gene.

Animals↗

PubMed2025

CRISPRoff epigenome editing for programmable gene silencing in human cell lines and primary T cells.

The advent of CRISPR-based technologies has enabled the rapid advancement of programmable gene manipulation in cells, tissues, and whole organisms. An emerging platform for targeted gene perturbation is epigenetic editing, the direct editing of chemical modifications on DNA and histones that ultimately results in repression or activation of the targeted gene. In contrast to CRISPR nucleases, epigenetic editors modulate gene expression without inducing DNA breaks or altering the genomic sequence of host cells. Recently, we developed the CRISPRoff epigenetic editing technology that simultaneously establishes DNA methylation and repressive histone modifications at targeted gene promoters. Transient expression of CRISPRoff and the accompanying single guide RNAs in mammalian cells results in transcriptional repression of targeted genes that is memorized heritably by cells through cell division and differentiation. Here, we describe our protocol for the delivery of CRISPRoff through plasmid DNA transfection, as well as the delivery of CRISPRoff mRNA, into transformed human cell lines and primary immune cells. We also provide guidance on evaluating target gene silencing and highlight key considerations when utilizing CRISPRoff for gene perturbations. Our protocols are broadly applicable to other CRISPR-based epigenetic editing technologies, as programmable genome manipulation tools continue to evolve rapidly.

Humans↗

PubMed2025

Identification of BoRR gene family in cauliflower: roles in curd development and salt tolerance.

BACKGROUND: Cauliflower, as an important vegetable crop, the research on its curd formation mechanism and stress-responsive gene networks is of great significance for improving its quality, yield and abiotic stress tolerance. The response regulator (RR) gene family plays a crucial role in the regulation of various life processes of many organisms. In this research, a comprehensive analysis of the BoRR gene family in cauliflower was carried out. RESULTS: A Total of 57 BoRR genes were identified in cauliflower and classified into seven subtypes (type A/B-I/B-II/B-IV/C/B-PRR/Clock PRR) based on sequence homology. Chromosomal mapping showed even distribution across genomes, while physicochemical analysis revealed diverse protein properties (134-915 amino acids, pI 4.51-9.19) with predominant nuclear localization. Structural analyses found all BoRR proteins contain REC-type domains, with subtype-specific features: type A has REC_typeA_ARR, type B harbors REC_typeB_ARR domains, and Clock PRR shows circadian-related psREC_RR domains. Exon numbers range from 2 to 10, with type A BoRR genes having shorter CDS lengths. Collinearity analysis identified 28 pairs of gene duplicates (26 inter-chromosomal). Comparative analysis showed 133 collinear pairs with Brassica napus, 96 with Brassica. rapa, and only 1 with monocots specie (rice and maize). Promoter analysis identified hormone-responsive motifs (ABRE, TGACG), development-related elements (ARE), and stress-responsive sequences (e.g., MBS for drought tolerance) in the promoters of BoRR genes. GO enrichment linked BoRR genes to phosphorelay signaling, cytokinin/ethylene response, and developmental processes like meristem maintenance. Expression profiling during curd development showed type A genes (BoRR23/27/34/38/45) up-regulated in vegetative-reproductive transition, BoRR3/6/12/32/54 in curd enlargement, and several genes like BoRR49 in flower bud differentiation. Salt stress (1.5% NaCl) induced transient expression in 8 of 9 selected BoRR genes at day 1 after treatment. qRT-PCR validated their roles in developmental regulation and salt tolerance. CONCLUSION: This study provides valuable insights into the BoRR gene family in cauliflower, laying a foundation for further understanding its genetic mechanisms and potentially guiding efforts to enhance curd quality and salt tolerance in cauliflower.

Salt Tolerance↗

PubMed2026

Suppression of HIV-1 replication in CEM-A cell cultures by trans-splicing group I introns targeting PAS/PBS sequences and conditionally expressing ΔN-Bax.

Anti-HIV group I introns containing antisense guide sequences directed against the HIV-1 primer activation signal and primer-binding site (PAS/PBS) were designed and evaluated. Because PAS/PBS sequences are present in the viral RNA species examined, these RNAs can serve as trans-splicing substrates. The introns were active against both artificial target RNAs and viral RNA generated during infection. Cleavage and degradation of targeted viral RNA may have contributed to suppression, whereas inclusion of a 3' exon encoding the proapoptotic protein ΔN-Bax was associated with increased programmed cell death and may have augmented suppression of viral replication. In cultured CEM-A cells, transgene expression of these introns markedly suppressed HIV-1 replication, with p24 levels falling below the assay detection limit in selected clones. RESULTS: RT-PCR and sequence analysis detected splice products containing the expected PAS/PBS junctions. In the dual-luciferase assay, intron expression reduced normalized Gaussia luciferase signal by approximately 70% relative to the negative control. Qualitative Annexin V imaging and caspase-3 assays were consistent with infection-dependent apoptosis after ΔN-Bax splice-product formation. Transient expression of each intron in HEK293T cells followed by infection with VSV-G-pseudotyped HIV-1NL4-3 at an MOI of 2 reduced p24 levels by approximately 50% at 4 days post-infection. Construct 128L produced the strongest RT-PCR band under the tested conditions and was selected for subsequent experiments. A canonical splice product and a low-abundance noncanonical splice product were detected; both involved the intended HIV-derived target RNA, although transcriptome-wide off-target splicing was not assessed. Heterogeneous transformed HEK293T populations showed an approximately 2-log10 reduction in p24. In selected clonal HEK293T and CEM-A lines, p24 was below the assay detection limit at the measured endpoints, including up to 90 days after infection in some CEM-A clones. CONCLUSIONS: PAS/PBS-targeting group I introns suppressed HIV-1-associated p24 production in the tested cell-culture models. Linking the introns to a ΔN-Bax 3' exon was associated with infection-dependent apoptosis and may further limit viral replication and spread. The use of highly conserved, functionally constrained target sequences may reduce the likelihood of escape, but viral evolution and transcriptome-wide off-target effects were not assessed. This conditional death-upon-infection strategy warrants further evaluation in primary-cell and in vivo models.

Humans↗

PubMed2025

Activation of the imprinted Prader-Willi syndrome locus by CRISPR-based epigenome editing.

Epigenome editing with DNA-targeting technologies such as CRISPR-dCas9 can be used to dissect gene regulatory mechanisms and potentially treat associated disorders. For example, Prader-Willi syndrome (PWS) results from loss of paternally expressed imprinted genes on chromosome 15q11.2-q13.3, although the maternal allele is intact but epigenetically silenced. Using CRISPR repression and activation screens in human induced pluripotent stem cells (iPSCs), we identified genomic elements that control the expression of the PWS gene SNRPN from the paternal and maternal chromosomes. We showed that either targeted transcriptional activation or DNA demethylation can activate the silenced maternal SNRPN and downstream PWS transcripts. However, these two approaches function at unique regions, preferentially activating different transcript variants and involving distinct epigenetic reprogramming mechanisms. Remarkably, transient expression of the targeted demethylase leads to stable, long-term maternal SNRPN expression in PWS iPSCs. This work uncovers targeted epigenetic manipulations to reprogram a disease-associated imprinted locus and suggests possible therapeutic interventions.

Prader-Willi Syndrome↗

PubMed1979

Selective loss of noradrenergic phenotypic characters in neuroblasts of the rat embryo.

To define the fate of embryonic neuroblasts in rat gut, which transiently express several noradrenergic traits, we investigated the high-affinity uptake of norepinephrine. At 12.5 days of gestation, these cells exhibited immunoreactivity to tyrosine hydroxylase [tyrosine 3-monoxygenase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] and endogenous catecholamine fluorescence. However, by 13.5 days these noradrenergic neurotransmitter phenotypic characters essentially disappeared. In contrast, norepinephrine uptake, which was also apparent at 12.5 days, persisted at least through 17.5 days. These observations indicate that norepinephrine uptake develops as an additional noradrenergic characteristic in these cells and persists after the disappearance of other noradrenergic traits. Consequently, neurotransmitter phenotypic characters may be transiently displayed during normal development in vivo.

Adrenergic Fibers↗

PubMed2026

Identification of tomato leaf miner secretory proteins and their roles in influencing plant defenses.

The tomato leaf miner (Tuta absoluta) is a globally destructive pest that cause extensive damage to tomato crops by chewing mouthparts, leading to severe necrosis, fruit abortion, and substantial yield losses. To date, the elicitors/effectors of T. absoluta have not been characterized. In this study, we combined proteomic profiling of T. absoluta-infested tomato leaves with transcriptomic analysis of salivary glands to identify candidate molecules involved in herbivory-driven plant responses. Bioinformatics analyses predicted 40 candidate elicitors and effectors, which were subsequently assessed through transient expression assays in Nicotiana benthamiana. The results demonstrated that the candidate number 33 (T. absoluta 33, Ta33) induced cell death in both the intracellular space and the apoplast, while Ta21 triggered a strong apoplastic reactive oxygen species (ROS) burst. Conversely, Ta38 effectively suppressed INF1-induced cell death. Quantitative real-time PCR analysis further showed that these genes were highly expressed during the feeding stage, supporting their involvement in plant-insect molecular dialogue. This study systematically identified and characterized elicitors and effectors of T. absoluta, providing a foundational framework for elucidating its herbivory mechanisms and developing targeted management strategies.

Moths↗

PubMed2026

Establishment of a cBSA-mediated miRNA delivery system in Camellia sinensis and functional validation of the Cs-miR163/CsSK1 module in cold stress response.

Cold stress severely limits tea (Camellia sinensis) yield and quality. MicroRNAs (miRNAs) are key post-transcriptional regulators of plant cold responses; however, in vivo functional validation in tea plants is hindered by the lack of efficient genetic transformation and nucleic acid delivery systems. In this study, a cationized bovine serum albumin (cBSA)-mediated miRNA delivery system was established in tea plants. The cold-responsive miRNA Cs-miR163 and its target gene CsSK1 (a negative regulator of cold tolerance) were used as a model. Direct cleavage of CsSK1 mRNA by Cs-miR163 was confirmed by 5' RLM-RACE and GUS transient expression assays, and enhanced cold tolerance was demonstrated in Arabidopsis overexpression lines. The cBSA preparation protocol was optimized, yielding stable cBSA/miRNA complexes with high protective capacity across temperatures of 15-35 °C and pH 4.5-7.2. Delivery parameters were systematically evaluated; optimal conditions were determined as 2 mg/mL cBSA with 10 nM miRNA and solution uptake into 3-cm cuttings for 5 days, enhancing miRNA delivery efficiency by approximately 48-fold. Transmission electron microscopy provided direct ultrastructural evidence that cBSA/miRNA nanocomplexes are internalized into tea plant cells via adsorptive-mediated endocytosis involving electrostatic membrane adsorption, membrane invagination, and cytoplasmic release. Under optimized conditions, cBSA-mediated delivery of Cs-miR163 silenced CsSK1 expression by approximately 72%, reduced relative electrolyte leakage and ROS accumulation, and markedly enhanced cold tolerance. The regulatory role of the Cs-miR163/CsSK1 module was clarified, and the established system provides a promising strategy for functional genomics in woody plants that warrants further testing in additional species and tissues.

Camellia sinensis↗

PubMed2026

A conserved COBL3-like protein promotes PDLP5-dependent callose accumulation to confer broad-spectrum plasmodesmata-mediated antiviral defense.

Plasmodesmata (PDs) play vital roles in plant growth and defense by controlling the symplastic transport of important molecules. Here we report that a conserved COBRA-like protein, COBL3, positively regulates callose accumulation and is required for PD-mediated antiviral defense (PMAD) against divergent plant RNA viruses in wheat (Triticum aestivum) and tobacco (Nicotiana benthamiana). The wheat COBL3 protein, TaCOBL3, interacts with the 17K movement protein (MP) of barley yellow dwarf virus-GAV (BYDV-GAV). TaCOBL3 is associated with the plasma membrane and co-localizes with 17K MP at PDs. Genetic analysis with overexpression and knockout lines revealed that TaCOBL3 positively regulates wheat defense against BYDV-GAV by modulating callose accumulation at PDs. Interestingly, TaCOBL3 interacts with the wheat homolog of PDLP5, a conserved key regulator of PD permeability in higher plants. Silencing TaPDLP5 attenuates the elevated BYDV-GAV defense conferred by overexpression of TaCOBL3 in wheat. Furthermore, transient expression of TaCOBL3 promotes callose accumulation and lowers PD permeability in tobacco cells, and these effects are largely compromised when tobacco PDLP5 is silenced. Notably, BYDV 17K MP weakens the interaction between TaCOBL3 and TaPDLP5 and inhibits their callose-binding activities. Finally, silencing of tobacco NbCOBL3 reduces callose content and attenuates host defense against two tobraviruses, one potexvirus, and one hordeivirus. Overall, our study reveals a previously unknown role of COBRA-like proteins in PMAD and provides insight into how a plant viral MP sabotages PMAD by perturbing the COBL3-PDLP5 interaction to facilitate virus spread through PDs. The conserved COBL3 gene may be a valuable target for engineering of broad-spectrum antiviral resistance in crop plants.

COBRA-like protein↗